Diversity of Slime Moulds (Eumycetozoa) in Three Forest Nature Reserves of the Knyszyn Forest, Poland

Abstract

The Knyszyn Forest is one of the major lowland forest complexes of north-eastern Poland, yet its myxobiota remains insufficiently documented. We surveyed Eumycetozoa in three forest nature reserves—Krzemianka, Jałówka, and Las Cieliczański—to assess local species richness, substrate occurrence, and new distributional records. Field surveys were combined with moist-chamber cultures, and species were identified from mature sporocarps using macro- and microscopic morphology. The inventory yielded 761 occurrence records representing 80 identified taxa. Moist-chamber cultures produced more records and species than field collection, while field surveys detected taxa fruiting naturally during the study period; together, both methods produced a more complete inventory than either method alone. Three species, Paradiacheopsis solitaria, Macbrideola rutilipedata, and Licea operculata, were recorded for the first time in Poland; these national novelties were included among the 14 taxa recorded for the first time in north-eastern Poland. Most records came from dead wood and bark, although other dead organic substrates also contributed to the recorded substrate spectrum. The resulting dataset provides a regional baseline for future biodiversity surveys in the Knyszyn Forest.

1. Introduction

Slime moulds (Eumycetozoa) are a diverse group within the phylum Amoebozoa and include three principal lineages: Myxogastria, Dictyostelia and Protosporangiida [1,2]. Because most species produce fungus-like, collectable sporocarps, they have traditionally been studied within mycology [2,3]. Biodiversity inventories generally focus on sporocarp-forming slime moulds, especially Myxomycetes (Myxogastria), together with taxa such as Ceratiomyxa, which is currently placed in Protosporangiida [1,4]. Mature sporocarps provide the principal macroscopic and microscopic characters used for taxonomic documentation.

The life cycle of plasmodial slime moulds includes microscopic trophic stages, either myxamoebae or swarm cells, and plasmodia that move through moist substrates before producing sporocarps [2,5]. As most inventories identify taxa from mature sporocarps, occurrence records mainly document the detectable fruiting stage and only partly reflect the biological presence of a taxon.

In forest ecosystems, slime moulds are best understood as components of detrital food webs, rather than as decomposers functionally equivalent to saprotrophic fungi. Their trophic stages graze on bacteria, yeasts, fungal spores and other microorganisms associated with decaying organic matter, linking microbial activity with nutrient cycling in dead wood, bark, litter and humus-rich microhabitats [2,6]. Moisture is especially important because it supports both plasmodial movement and the microbial prey base on which these organisms depend. Forest stands with shaded, humid and structurally diverse substrates can therefore support rich myxobiota.

Slime moulds remain under-recorded in many biodiversity inventories. Their sporocarps are often minute, seasonal and short-lived, and their appearance depends on brief combinations of moisture, temperature, substrate condition and light [5,7,8]. Thus, a single field visit may record only a small part of the local myxobiota. Protected forests and nature reserves are particularly valuable reference sites for inventories because they often retain diverse dead organic substrates, canopy shade, hydrological heterogeneity and relatively low levels of direct disturbance [9,10].

Substrate properties are key ecological descriptors in slime mould inventories. Substrate type, host or substrate species, bark and wood structure, decomposition stage, moisture retention and pH can influence slime mould development and the probability of sporocarp formation [6,8]. Substrate and habitat context are therefore essential for interpreting occurrence records in forest inventories.

Field collection and moist-chamber culture provide complementary approaches for documenting Eumycetozoa. Field surveys mainly record larger, macroscopically visible sporocarps that develop under natural conditions and are often not produced in moist-chamber cultures. Moist-chamber cultures, in turn, induce sporulation on collected substrates and reveal taxa that may be overlooked during field visits [5,8,11]. Together, these methods recover partly different components of the assemblage, increasing taxonomic coverage and reducing method-specific bias in biodiversity inventories.

European and Polish slime mould records are extensive but spatially uneven. In Poland, classical mycological and taxonomic syntheses, including the monograph of Krzemieniewska and the national checklist of Drozdowicz and co-authors, provide the main historical framework for comparison [12,13]. North-eastern Poland contains several important protected forest and wetland complexes, yet documentation of slime moulds is concentrated in relatively few areas, especially the Białowieża Forest and Wigry National Park, while other lowland forests and wetland systems remain much less thoroughly studied [9,10,14,15].

Within this regional context, the Knyszyn Forest remains insufficiently documented for Eumycetozoa. The only previous study directly focused on slime moulds in this forest complex was a moist-chamber survey of swamp forest stands, which substantially improved the local record base but was limited in spatial and methodological scope [3]. Published data therefore remain fragmentary, and large-scale reserve-level documentation of slime moulds in the Knyszyn Forest has been lacking. A broader inventory across protected forest reserves is needed to place local records in a regional context.

Krzemianka, Jałówka and Las Cieliczański Nature Reserves were selected because they are protected forest sites within the Knyszyn Forest and represent different local habitat and substrate conditions. Together, they provide a suitable framework for comparing slime mould diversity across protected lowland forest habitats [16,17,18,19].

The present article provides an inventory of slime mould diversity in three forest nature reserves of the Knyszyn Forest [20]. The aims were to document slime mould diversity, describe diagnostic morphology and habitat occurrence, compare reserves and acquisition methods, and provide a regional reference for future studies of Eumycetozoa in north-eastern Poland.

2. Materials and Methods

2.1. Study Area

The study was conducted in the Knyszyn Forest (Puszcza Knyszyńska), Podlaskie Voivodeship, north-eastern Poland, in three forest nature reserves: Krzemianka Nature Reserve, Jałówka Nature Reserve and Las Cieliczański Nature Reserve. The Knyszyn Forest is a large lowland forest complex of high ecological and conservation value. It includes diverse coniferous, mixed broadleaved, alder, riparian, spring-fed and peatland-related forest habitats, where shaded, humid conditions and abundant dead wood create numerous microhabitats suitable for slime moulds.

Meteorological data were used to characterise the fieldwork period. Monthly mean air temperature, monthly precipitation totals and mean monthly relative humidity for June–November 2025 were extracted from the IMGW-PIB Rocznik Meteorologiczny 2025 for the Białystok synoptic station. These data were treated as a regional open-air climatic reference for all three reserves, not as measurements of under-canopy microclimate [21,22]. The monthly values used in the study are listed in Table 1.

Table 1. Monthly meteorological data used as a regional station-based climatic reference for the fieldwork period in the three studied Knyszyn Forest reserves.

Month	Mean Air Temperature (°C)	Monthly Precipitation (mm)	Mean Relative Humidity (%)
June 2025	17.2	47.1	68
July 2025	19.1	79.8	75
August 2025	17.6	17.9	71
September 2025	15.7	42.3	78
October 2025	7.4	85.4	87
November 2025	3.4	43.9	92

2.1.1. Krzemianka Nature Reserve

Krzemianka Nature Reserve is located in the western part of the Knyszyn Forest, in Białystok County, Podlaskie Voivodeship, within the communes of Dobrzyniewo Duże and Czarna Białostocka. The reserve covers 230.63 ha and is situated mainly on State Treasury land administered by the Knyszyn Forest District. The representative WGS84 locality point used for spatial assignment of the site was 53.28353° N, 23.11159° E [16,17,23].

Krzemianka is classified as a forest reserve with a phytocoenotic conservation profile, representing forest and mixed-forest lowland ecosystems. Its formal conservation objective is to preserve forest ecosystems characteristic of the Knyszyn Forest, spring areas and localities of rare and protected plant and animal species [16,17]. In the present study, Krzemianka was treated as a spring-fed forest–wetland complex with lowland mixed forests, peatland fragments, natural watercourses and groundwater-fed habitats.

2.1.2. Jałówka Nature Reserve

Jałówka Nature Reserve is located in the Knyszyn Forest in the commune of Supraśl, Białystok County, Podlaskie Voivodeship. The reserve covers 277.42 ha and is situated on State Treasury land administered by the Supraśl Forest District. The representative WGS84 locality point used for spatial assignment of the site was 53.230164° N, 23.344152° E [18,24,25].

Jałówka is classified as a forest reserve with a phytocoenotic conservation profile and a lowland mixed-forest ecosystem type. Its conservation objective is to preserve a valuable fragment of the Knyszyn Forest, including characteristic geomorphological systems and rich plant communities [18]. Ecologically, the reserve represents a heterogeneous forest–peatland complex with varied relief, diverse site conditions, spring areas and high vegetation naturalness [24,25]. Wet and fresh forest habitats with dead wood, decaying bark, logs, branches, stumps, litter and bryophyte-covered substrates provide suitable microhabitats for sporocarp-forming slime moulds.

2.1.3. Las Cieliczański Nature Reserve

Las Cieliczański Nature Reserve is located in the Knyszyn Forest in Białystok County, Podlaskie Voivodeship, within the communes of Gródek and Supraśl. The reserve covers 370.58 ha and lies on State Treasury land administered by the Dojlidy and Żednia Forest Districts. The representative WGS84 locality point used for spatial assignment of the site was 53.17970° N, 23.36100° E [19,26,27].

The reserve was established to preserve a fragment of the Knyszyn Forest with valuable forest communities of natural character. Documented communities include oak–hornbeam forests, especially stands with wych elm Ulmus glabra Huds., mixed coniferous forests and alder carrs [19,26]. The protection plan identifies several habitat types relevant to the forest and wetland system, including subcontinental oak–hornbeam forest 9170, bog woodland 91D0, alluvial forests 91E0 and active raised bog 7110 [19]. Spring-fed streams and peat-filled depressions are associated with alder-dominated and ash–alder riparian patches, whereas mineral elevations support oak–hornbeam communities.

The study-area map was prepared in QGIS using the PUWG 1992 projected coordinate system (EPSG:2180) and a WGS 84 geographic grid (EPSG:4326) [28]. The Knyszyn Forest and the three studied reserves are shown in Figure 1.

Figure 1. Location of the Knyszyn Forest and the three studied nature reserves in north-eastern Poland. The Knyszyn Forest is marked in orange; Krzemianka Nature Reserve is marked in blue, Jałówka Nature Reserve in red, and Las Cieliczański Nature Reserve in green. Additional panels show the individual reserve areas.

2.2. Sampling and Cultures

Field surveys were conducted from June to November 2025. Moist-chamber cultures were established in three rounds during the same period and maintained until February 2026. March–April 2026 was devoted mainly to morphological analyses, microscopic photography and taxonomic identification. In total, 39 field visits were carried out: 14 in Krzemianka, 13 in Las Cieliczański, and 12 in Jałówka. Sampling intensity varied slightly among reserves and months; the number of visits ranged from zero to four per reserve per month.

2.2.1. Field Sampling

Field sampling was conducted in the three studied reserves along existing forest roads, paths and accessible forest routes. Formal transects, plots and quadrats were not established. Sampling locations were selected opportunistically along these routes to cover the main habitat mosaics and substrate types present in each reserve. For the route-based field component, no fixed number of sampling units was allocated to individual forest compartment or forest site type; their representation was therefore summarised post hoc using occurrence-record counts Visible mature sporocarps were searched for with a 15× or 25× hand lens. At each sampling point, the main available dead organic substrates were inspected, including dead wood, bark, litter, bryophytes, herbaceous remains, twigs, stumps and other substrates. Dead wood comprised logs, fallen trunks, branches, twigs less than 2 cm in diameter, stumps and other coarse or fine woody debris. Lying dead wood was left in place, and dead bark was not removed from stumps, logs or dead trunks except when a very small fragment was needed to collect sporocarps. Bark surfaces were inspected where they were naturally accessible.

Field-collected sporocarps were removed together with a thin fragment of the underlying substrate using a knife, razor blade or fine pin. Each collection was labelled with a specimen number, reserve or sampling area, collection date and substrate information. Field notes included at least the substrate type and, where available, substrate species, forest address, habitat context and accompanying microhabitat observations. The full set of record-level variables is described in Section 2.4 and in the deposited dataset [20].

2.2.2. Substrate Sampling for Moist-Chamber Cultures

Substrate sampling for moist-chamber cultures used four substrate categories: W = wood, B = bark, L = leaves or leaf litter, and T = twigs. Broadleaved tree species were represented by wood, bark, leaves and twigs, whereas coniferous tree species were represented by wood, bark and twigs.

The substrate and tree-species combinations used in the three reserves are summarised in Table 2. Across the three sampling rounds, this design yielded 522 moist-chamber cultures in total.

Table 2. Tree species and substrate categories used for moist-chamber cultures in the three studied reserves. W = wood, B = bark, L = leaves or leaf litter, and T = twigs. The symbols + and – indicate that the substrate category was included or not included in the moist-chamber design, respectively.

Reserve	Tree Species	W	B	L	T
Jałówka Nature Reserve	Alnus glutinosa	+	+	+	+
Jałówka Nature Reserve	Betula pendula	+	+	+	+
Jałówka Nature Reserve	Picea abies	+	+	–	+
Jałówka Nature Reserve	Pinus sylvestris	+	+	–	+
Jałówka Nature Reserve	Quercus robur	+	+	+	+
Krzemianka Nature Reserve	Alnus glutinosa	+	+	+	+
Krzemianka Nature Reserve	Betula pubescens	+	+	+	+
Krzemianka Nature Reserve	Carpinus betulus	+	+	+	+
Krzemianka Nature Reserve	Picea abies	+	+	–	+
Krzemianka Nature Reserve	Pinus sylvestris	+	+	–	+
Krzemianka Nature Reserve	Quercus robur	+	+	+	+
Las Cieliczański Nature Reserve	Alnus glutinosa	+	+	+	+
Las Cieliczański Nature Reserve	Betula pendula	+	+	+	+
Las Cieliczański Nature Reserve	Picea abies	+	+	–	+
Las Cieliczański Nature Reserve	Pinus sylvestris	+	+	–	+
Las Cieliczański Nature Reserve	Quercus robur	+	+	+	+

2.2.3. Moist-Chamber Cultures

Moist-chamber cultures followed the general approach used in slime mould inventory studies [5,8,11] and in previous work on slime moulds in the Knyszyn Forest [3]. Standardised glass Petri dishes of 9 cm diameter were used. Substrate fragments were placed on a double layer of sterilised cellulose tissue in each dish, in an amount sufficient to cover the bottom while still allowing the lid to close completely. Each chamber received 15–20 mL of distilled water and was assigned a unique culture code linked to the reserve, substrate type, substrate species, setup date and harvest date.

Substrate pH was measured 36–48 h after culture setup. Excess soaking water was decanted, and the pH of this water was measured with an SP 300 portable laboratory pH meter. Before measurement, the meter was calibrated with standard pH 4.00 and pH 7.00 buffer solutions, following a two-point calibration procedure appropriate for acidic to weakly acidic substrates. After pH measurement, the remaining water was drained so that the substrates remained moist but not submerged.

Cultures were incubated at room temperature, approximately 18–24 °C, under diffuse daylight. They were checked under a stereomicroscope every few days during the early phase of incubation and at least weekly thereafter, with additional checks when plasmodia or developing sporocarps were present. Distilled water was added sparingly when needed to prevent desiccation, while avoiding persistent flooding and excessive fungal growth. Plasmodia, sclerotia and immature sporocarps were documented when observed, but they were not counted as identified records unless they developed into mature sporocarps suitable for taxonomic identification. A moist chamber was treated as positive when mature, identifiable sporocarps were produced. Multiple taxa fruiting in the same chamber were recorded as separate taxon records, whereas repeated fruiting of the same taxon in the same moist chamber at a later date was merged with the earlier record.

Mature sporocarps obtained from field collections and moist-chamber cultures were air-dried. After drying, specimens were frozen for 3–7 days to reduce the risk of damage by invertebrates and then stored in cardboard herbarium boxes as permanent vouchers. All vouchers are curated under their specimen or moist-chamber codes in Tomasz Pawłowicz’s Slime Mould Collection at the Institute of Forest Sciences, Białystok University of Technology. For taxa recorded more than 10 times, representative vouchers were prepared from selected occurrences.

2.3. Identification

Diagnostic identification was based exclusively on the morphology of mature sporocarps and their microscopic structures. The study therefore reports morphology-based determinations of slime moulds; molecular sequencing was not undertaken because the study was designed as a sporocarp-based inventory using established morphological criteria, rather than as a molecular taxonomic revision. This decision was also supported by current limitations of DNA barcoding in Myxomycetes, including incomplete reference databases and variable amplification and discriminatory performance of commonly used markers among taxa, which limit its uniform application across all records. Material assigned to Myxomycetes (Myxogastria) and Protosporangiida was examined from both field collections and moist-chamber cultures.

Macroscopic and stereomicroscopic documentation was obtained with an Opta-Tech SK binocular microscope. Micromorphological observations and photographs were made with an Opta-Tech LAB 40 compound microscope equipped for digital imaging. Laboratory microscopy used 4×, 10×, 40× and 100× objectives, and quantitative measurements were made with a 100× oil immersion objective. Temporary microscopic preparations were mounted in 3% KOH. Spore diameter was measured including surface ornamentation.

Identification considered the main diagnostic characters of sporocarps, including peridium, stalk, hypothallus, columella, capillitium or elaters, lime structures, spore colour, ornamentation and diameter. Records based on immature, degraded or otherwise non-diagnostic material were excluded from taxon-level analyses unless later collections from the same record or chamber yielded mature fruiting bodies.

Species-level determinations were made primarily using the three-volume monographic key series Die Myxomyceten by Neubert et al. [29,30,31], supplemented by The Myxomycetes by Martin and Alexopoulos [32], as reproduced in the digital compilation prepared by Rojas and Lado [4]. Taxonomic nomenclature follows the online nomenclatural information system for Eumycetozoa by Lado [4], accessed on 13 May 2026. Names used in the older literature and regional checklists were cross-checked against this nomenclatural framework to ensure consistency. The taxonomic treatment in Appendix A provides morphological descriptions and information on substrates and habitats for all recorded taxa, together with taxonomic remarks where relevant.

2.4. Data and Environment

The record-level occurrence dataset is deposited in Mendeley Data as “Dataset—Slime Moulds (Eumycetozoa) in Three Forest Nature Reserves of the Knyszyn Forest” [20]. It contains 761 records representing 80 identified taxa and distinguishes field-survey records from moist-chamber records. The dataset includes taxonomic, acquisition-method, date, substrate, pH, spatial, collector, determiner and forest-habitat variables. For moist-chamber records, Collection Date refers to the date when mature sporocarps were harvested; for field records, it refers to the field collection date.

Forest habitat and environmental descriptors were derived from the Bank Danych o Lasach (BDL, Forest Data Bank) where available [33]. These descriptors included Full Forest Address, Forest District, Forest Site Type, Degradation Degree, Moisture Variant, Plant Community and Natural Habitat Code. Degradation Degree was recorded using BDL habitat transformation categories such as Natural (N1), Near-Natural (N2) or Distorted (Z1). Moisture Variant included categories such as Fresh, Moist, Wet, Flooded or Not Flooded. Natural Habitat Code could contain multiple Natura 2000 habitat codes separated by semicolons. These descriptors were used to contextualise occurrence records and support descriptive summaries.

National and regional novelty assessment was conducted by comparing the accepted taxon names from the present inventory with two checklist datasets. Records later reported as first records for Poland were checked against the national checklist dataset “Recorded and predicted occurrence of Eumycetozoa in Poland from Central and Eastern European data” [34]. Records later reported as first records for north-eastern Poland were checked against the regional checklist dataset “Checklist of Slime Moulds Recorded in North-Eastern Poland” [35]. North-eastern Poland is used as an operational geographic term and is defined as the complete administrative area of two voivodeships: Warmian-Masurian Voivodeship and Podlaskie Voivodeship. The comparison was made after nomenclatural standardisation according to Lado [4]. The resulting novelty categories are reported in Section 3.

The fieldwork-period meteorological data described in Section 2.1 were used only as descriptive climatic context for the route-based field surveys conducted from June to November 2025.

2.5. Statistical Analyses

All statistical analyses were conducted in R 4.5.2 [36]. Data import, cleaning, diversity analysis, rarefaction, post hoc testing, table export and plotting used readxl, tidyverse, janitor, vegan, iNEXT, FSA, openxlsx and ggplot2 [37,38,39,40,41,42,43,44,45].

Each row was treated as one occurrence record. Record counts were interpreted as occurrence frequencies and do not represent numbers of individuals, population size, density or true biological abundance. Analyses used taxon, acquisition method, reserve, substrate, pH and forest-habitat variables. Substrate classes followed the substrate–microhabitat framework of Pawłowicz and Oszako [46] and included corticolous, lignicolous, ramicolous, foliicolous, bryophilous, herbaceous, terricolous and miscellaneous substrates. Each record was assigned to one dominant substrate class.

Before analysis, categorical values were standardised by trimming leading and trailing spaces, reducing repeated internal spaces and converting blank or non-informative entries to missing values. Taxon names were not taxonomically recoded except for the removal of formatting artefacts. Substrate pH values written with decimal commas were converted to decimal points and then to numeric values. Values outside the physically possible pH range were excluded from pH summaries. Semicolon-separated Natural Habitat Code values were split into individual record–habitat code occurrences for habitat summaries; therefore, totals in expanded habitat code tables may exceed the original number of records.

Inventory structure was summarised as the number of records and taxa for the full dataset, each reserve, each acquisition method and each reserve-by-method combination. Taxon record frequencies were used to identify the most frequently recorded taxa, singletons, doubletons, taxa recorded only in individual reserves during the present survey, taxa shared by pairs of reserves, taxa shared by all three reserves, and taxa detected by field collection, moist-chamber culture or both methods.

Alpha diversity was calculated from record frequency matrices. For each reserve, acquisition method and substrate class, observed taxon richness was reported together with Shannon diversity $H^{\prime }$ [47], Simpson diversity expressed as 1–D [48], inverse Simpson diversity, Pielou evenness J [49], and Hill numbers for $q=0$, $q=1$ and $q=2$ [50]. These metrics describe the structure of occurrence records and were interpreted as record-based inventory statistics.

Record-based richness standardisation diagnostics were calculated by reserve using rarefaction and extrapolation, sample coverage and Chao1 estimated richness [51,52]. The iNEXT framework was used for interpolation and extrapolation of taxon richness from record frequency vectors, with 95% confidence intervals where available [42]. Observed richness was also expressed as the ratio of observed to estimated Chao1 richness.

Reserve-level similarity was evaluated using a taxon-by-reserve presence/absence matrix and a taxon-by-reserve record frequency matrix. Jaccard similarity [53] and Sørensen similarity [54] were used as the primary inventory-based similarity measures because they are based on presence/absence. Bray–Curtis dissimilarity [55] was calculated as a secondary record frequency measure.

Associations between categorical variables were tested only where the contingency-table structure was suitable for inference. Pearson chi-square tests were used when expected counts were adequate; otherwise, Fisher’s exact tests with simulated p-values were used. Cramér’s V was reported as an effect size. These tests were applied to reserve-by-acquisition-method, reserve-by-substrate-class, acquisition-method-by-substrate-class, reserve-by-forest-site-type and reserve-by-natural-habitat-code tables where appropriate. A threshold of $p<0.05$ was used for exploratory significance testing.

Substrate analyses summarised record frequency and taxon richness by substrate class and substrate species. Taxon-by-substrate matrices were used to describe substrate occurrence patterns. For visualisation, the substrate heat map was restricted to the 20 taxa with the highest total record frequencies to improve readability.

Substrate pH was analysed only for records with numeric pH values, all of which were moist-chamber records. Overall pH summaries included the range, mean, median, standard deviation and interquartile range. pH was summarised by reserve, substrate class and frequent substrate species. Differences in pH among substrate classes and among reserves were tested using Kruskal–Wallis rank-sum tests [56] when group sizes were sufficient. Dunn post hoc tests [57] with Benjamini–Hochberg correction [58] were applied only after significant Kruskal–Wallis tests.

Forest habitat descriptors were analysed using forest site type, plant community and natural habitat code. Habitat summaries included record counts, taxon richness, reserve representation, most frequent substrate classes and the most frequent taxa within each habitat category. Statistical outputs were interpreted as descriptive summaries of an inventory dataset.

3. Results

3.1. Taxonomy

The full taxonomic treatment is provided in Appendix A, which includes species-level descriptions for all recorded taxa and photographic documentation of characteristic morphological features for most of them.

Three species are reported here as new records for Poland: Paradiacheopsis solitaria, Macbrideola rutilipedata and Licea operculata. Fourteen species are reported as new records for north-eastern Poland, including the three national novelties listed above: Comatricha rigida, Paradiacheopsis solitaria, Stemonitopsis amoena, Stemonitopsis gracilis, Arcyria marginoundulata, Clastoderma debaryanum, Cribraria languescens, Cribraria oregana, Cribraria violacea, Diderma saundersii, Licea operculata, Physarum pusillum, Macbrideola rutilipedata and Oligonema flavidum.

3.2. Inventory and Taxonomic Composition

The final dataset comprised 761 occurrence records of slime moulds from Jałówka, Krzemianka and Las Cieliczański Nature Reserves. In total, 80 taxa were identified, representing 35 genera and 15 families. Of these, 78 taxa belonged to Myxomycetes/Myxogastria, whereas two species were represented by Ceratiomyxa (Protosporangiida). Field collection yielded 257 records and 49 taxa, whereas moist-chamber culture yielded 504 records and 67 taxa. Krzemianka had the highest reserve-level record number and taxon richness; full summaries by reserve and acquisition method are provided in Table 3.

Table 3. Inventory summary for slime moulds recorded in the three studied nature reserves of the Knyszyn Forest. MC—moist-chamber culture. Records are occurrence records and are not interpreted as organism abundance. The final column lists taxa detected exclusively in a given reserve.

Reserve	Records	Taxa	Field Records	MC Records	Field Taxa	MC Taxa	Taxa Recorded Exclusively in a Given Reserve
Jałówka Nature Reserve	242	59	80	162	30	47	4
Krzemianka Nature Reserve	277	64	79	198	30	51	6
Las Cieliczański Nature Reserve	242	58	98	144	34	44	8
Total	761	80	257	504	49	67	18

The most frequently recorded taxa in the full dataset were Arcyria cinerea with 67 records, Ceratiomyxa fruticulosa with 57 records, the Lycogala epidendrum complex with 56 records, Physarum album with 53 records, Heterotrichia pomiformis with 49 records and Fuligo septica with 47 records. The record frequency distribution included 13 singleton taxa and 14 doubleton taxa; all remaining taxa were represented by three or more records.

3.3. Diversity and Reserve Similarity

Reserve-level alpha diversity was broadly similar among the three reserves, although the highest observed taxon richness occurred in Krzemianka. Shannon and Simpson diversity were highest in Jałówka, and evenness values were comparable among reserves (Table 4).

Table 4. Reserve-level alpha diversity based on record frequency data. S—observed taxon richness; $H^{\prime }$—Shannon diversity; 1–D—Simpson diversity; J—Pielou evenness.

Reserve	Records	S	${\mathit{H}}^{\prime }$	1–D	J	Hill $\mathit{q}=1$	Hill $\mathit{q}=2$
Jałówka Nature Reserve	242	59	3.562	0.959	0.874	35.23	24.32
Krzemianka Nature Reserve	277	64	3.549	0.955	0.853	34.79	22.12
Las Cieliczański Nature Reserve	242	58	3.500	0.953	0.862	33.10	21.40

Record-based rarefaction and extrapolation curves provided a record-standardised view of richness patterns among reserves. In this record frequency dataset, Krzemianka reached the highest observed and estimated richness (Figure 2). Coverage values exceeded 0.90 in all reserves, and observed richness remained below Chao1 estimates in each reserve (Table 5).

Figure 2. Record-based rarefaction and extrapolation curves for slime mould taxa in Jałówka, Krzemianka and Las Cieliczański Nature Reserves. Curves are based on occurrence-record frequency vectors and show relative richness trajectories among reserves.

Table 5. Record-based richness-estimation diagnostics by reserve. Chao1 and coverage values were calculated from occurrence-record frequencies.

Reserve	Coverage	Chao1	Observed/Chao1	Singletons	Doubletons
Jałówka Nature Reserve	0.905	79.26	0.744	23	13
Krzemianka Nature Reserve	0.907	88.06	0.726	26	14
Las Cieliczański Nature Reserve	0.922	70.84	0.818	19	14

Thirty-nine taxa were recorded in all three reserves. Eighteen taxa were recorded exclusively in a single reserve during the present survey: four in Jałówka, six in Krzemianka and eight in Las Cieliczański. Among pairwise intersections, 12 taxa were shared only by Jałówka and Krzemianka, seven only by Krzemianka and Las Cieliczański, and four only by Jałówka and Las Cieliczański. The distribution of shared taxa and those detected only in one reserve is shown in Figure 3.

Figure 3. Shared and unique slime mould taxa among the three studied nature reserves. Intersections are based on taxon presence/absence data and show taxa recorded exclusively in a single reserve, shared by reserve pairs or shared by all three reserves.

Presence/absence-based reserve similarity was highest between Jałówka and Krzemianka. Jaccard similarity was 0.708 for Jałówka–Krzemianka, 0.605 for Krzemianka–Las Cieliczański and 0.581 for Jałówka–Las Cieliczański (Figure 4). Sørensen similarity followed the same ranking, with values of 0.829, 0.754 and 0.735, respectively. Bray–Curtis dissimilarity based on the record frequency matrix was 0.210 for Jałówka–Krzemianka, 0.256 for Jałówka–Las Cieliczański and 0.314 for Krzemianka–Las Cieliczański.

Figure 4. Pairwise Jaccard similarity among Jałówka, Krzemianka and Las Cieliczański Nature Reserves based on taxon presence/absence data. Values are shown on a 0–1 scale.

Thirty-six taxa were detected by both field collection and moist-chamber culture. Thirteen taxa were detected only by field collection, whereas 31 taxa were detected only by moist-chamber culture. A Pearson chi-square test showed an association between reserve and acquisition method (${\chi }^2=8.363$, df = 2, $p=0.015$), with a small effect size (Cramér’s $V=0.105$).

3.4. Substrates and Habitats

Lignicolous substrates formed the largest substrate class, accounting for 456 records and 65 taxa. Corticolous and foliicolous substrates were the next most represented classes, whereas ramicolous, herbaceous, terricolous and bryophilous substrates contributed fewer records and taxa (Table 6). Lignicolous substrates were also the largest substrate class within each reserve.

Table 6. Substrate-class summary for slime mould records in the three studied reserves. Substrate classes follow the categories used in the statistical analyses.

Substrate Class	Records	Taxa	Taxa Recorded Only on Given Substrate Class
Lignicolous	456	65	20
Corticolous	172	39	7
Foliicolous	69	28	4
Ramicolous	29	6	1
Herbaceous	18	8	2
Terricolous	12	8	0
Bryophilous	5	4	0

The most frequent lignicolous taxa were Ceratiomyxa fruticulosa (53 records), Arcyria cinerea (33), the Lycogala epidendrum complex (31), Cribraria microcarpa (29) and Heterotrichia pomiformis (26). The most frequent corticolous taxa were Arcyria cinerea (27), the Lycogala epidendrum complex (25), Heterotrichia pomiformis (23), Physarum album (12) and Enerthenema papillatum (9). In the present dataset, 20 taxa were recorded exclusively on lignicolous substrates, seven on corticolous substrates, four on foliicolous substrates, two on herbaceous substrates and one on ramicolous substrates.

The taxon-by-substrate heat map for the 20 most frequently recorded taxa is shown in Figure 5. Ceratiomyxa fruticulosa was recorded most often on lignicolous substrates, whereas Arcyria cinerea, the Lycogala epidendrum complex, Heterotrichia pomiformis, Fuligo septica and Physarum album occurred across broader substrate combinations. Physarum album was recorded especially often on ramicolous substrates, with 18 records.

Figure 5. Taxon-by-substrate-class heat map for the 20 slime mould taxa with the highest total record frequencies. Cells represent occurrence-record frequencies for each taxon and substrate class.

Summaries by substrate species showed the highest record frequency and taxon richness for Quercus robur, with 158 records and 56 taxa. Other frequent substrate species included Betula pendula, Alnus glutinosa, Picea abies, Pinus sylvestris and Carpinus betulus. Substrate species was unrecorded for 105 records.

The pH values were measured in moist-chamber soaking water and refer only to the moist-chamber subset; they are not direct field measurements of soil, bark or wood pH. Numerical pH values were available for 504 records, corresponding to the moist-chamber subset. Across all pH records, values ranged from 3.69 to 7.02, with a mean of 4.947 and a median of 5.055. Reserve-level median pH values were similar. The Kruskal–Wallis test showed a statistically significant reserve-level difference, but the effect size was very small ($H=6.534$, df = 2, $p=0.038$, epsilon-squared = 0.009), indicating a weak difference among reserves in this dataset.

Among substrate classes with numeric pH values, ramicolous substrates had the highest median pH, followed by foliicolous, lignicolous and corticolous substrates. Kruskal–Wallis testing indicated differences in pH among substrate classes ($H=62.745$, df = 3, $p<0.001$, epsilon-squared = 0.119). Post hoc tests showed that most substrate-class pairs differed after correction, except corticolous and lignicolous substrates. The distribution of pH values by substrate class is shown in Figure 6.

Figure 6. Distribution of pH values measured in moist-chamber soaking water grouped by substrate class for records with numerical pH data. Boxes show medians and interquartile ranges; points represent individual moist-chamber records.

At the level of substrate species, the lowest median pH was recorded for Quercus robur (median = 3.95; 128 records with pH). Higher medians were recorded for Carpinus betulus (5.41), Pinus sylvestris (5.36), Betula pendula (5.185), Betula pubescens (5.17), Alnus glutinosa (5.02) and Picea abies (4.97).

Forest site type summaries showed that Fresh Mixed Broadleaved Forest Site was the most represented category, with 303 records and 62 taxa. Forest site type information was available for all 761 occurrence records, and their distribution by acquisition method across the 11 categories is summarised in Table 7. Lignicolous substrates were the largest substrate class in most forest site types.

Table 7. Distribution of the 761 occurrence records among Forest site type categories and acquisition methods. Counts represent taxon occurrence records; multiple taxa obtained from one moist chamber were recorded separately. MC—moist-chamber culture.

Forest Site Type	Field Records	MC Records	Total Records
Alder Swamp Forest Site	18	11	29
Ash-Alder Swamp Forest Site	23	39	62
Bog Mixed Broadleaved Forest Site	20	29	49
Bog Mixed Coniferous Forest Site	8	6	14
Fresh Broadleaved Forest Site	40	71	111
Fresh Mixed Broadleaved Forest Site	63	240	303
Fresh Mixed Coniferous Forest Site	44	76	120
Moist Broadleaved Forest Site	9	0	9
Moist Mixed Broadleaved Forest Site	22	17	39
Moist Mixed Coniferous Forest Site	6	14	20
Riparian Broadleaved Forest Site	4	1	5
Total	257	504	761

Plant community summaries showed the highest record number and richness in Tilio-Carpinetum, with 268 records and 66 taxa. Serratulo-Pinetum and Fraxino-Alnetum were also well represented, whereas the remaining plant communities contributed fewer records and taxa.

Among expanded natural habitat code occurrences, habitat code 9170 was the most represented category, followed by 91E0 and 91D0. Lignicolous substrates were the largest substrate class within all three natural habitat code categories.

The reserve-by-substrate-class association was not significant. Substrate class was associated with acquisition method, and habitat-level tests showed differences in the distribution of records among reserves for forest site type and natural habitat code. The reserve-by-plant-community contingency table was too sparse for testing. Statistical tests are summarized in Table 8.

Table 8. Summary of statistical tests used in the Results. Fisher’s exact tests used simulated p-values where contingency tables were sparse.

Comparison	Test	Statistic	df	p	Effect Size
Reserve × acquisition method	Pearson chi-square	8.363	2	0.015	Cramér’s $V=0.105$
Reserve × substrate class	Fisher, simulated	–	–	0.789	Cramér’s $V=0.071$
Substrate class × acquisition method	Fisher, simulated	–	–	<0.001	Cramér’s $V=0.321$
pH among substrate classes	Kruskal–Wallis	62.745	3	<0.001	${ϵ}^2=0.119$
pH among reserves	Kruskal–Wallis	6.534	2	0.038	${ϵ}^2=0.009$
Reserve × forest site type	Fisher, simulated	–	–	<0.001	Cramér’s $V=0.468$
Reserve × natural habitat code	Pearson chi-square	90.368	4	<0.001	Cramér’s $V=0.238$

4. Discussion

4.1. Regional Significance

The present study substantially expands the documented myxobiota of the Knyszyn Forest. Although this forest complex is one of the major lowland forest areas of north-eastern Poland, its slime mould diversity has received much less attention than that of Białowieża Forest, Wigry National Park and several other protected areas in the region [3,9,10,14,20]. The 761 occurrence records from three reserves therefore extend the local checklist by documenting a previously under-recorded component of the regional myxobiota and link each record with acquisition method, substrate, pH and forest habitat context [20].

The recorded richness is high for a focused inventory of three forest reserves. It remains below the best documented long-term datasets from north-eastern Poland, including Białowieża Forest, for which later syntheses reported 127 species, and Wigry National Park, where 129 taxa, including 124 species and five varieties, were recorded [9,10,14,59]. At the same time, it exceeds several shorter or habitat-focused Polish inventories [3,15,60,61,62]. This comparison suggests that the three studied reserves contain a well-developed local component of the regional myxobiota, while the wider Knyszyn Forest is still likely to be incompletely documented.

The distributional results are also relevant at national and regional scales. According to the checklist datasets used in this study, Paradiacheopsis solitaria, Macbrideola rutilipedata and Licea operculata represent first records for Poland, and 14 species in total, including these three, represent first records for north-eastern Poland [20,34,35]. These records indicate that the apparent rarity of some taxa may partly reflect uneven regional sampling. In this context, the Knyszyn Forest is not only a poorly documented area, but also a likely source of further records important for understanding the distribution of Eumycetozoa in Poland.

4.2. Diversity Patterns

The three reserves showed broadly similar observed richness, although Krzemianka had the highest number of records and taxa. Diversity metrics indicate that the recorded myxobiota did not consist only of a few highly frequent species. The dataset instead contains a shared core of common forest taxa together with a substantial number of less frequent taxa detected in only one reserve during this survey. This structure is consistent with forest slime mould inventories, in which widespread taxa are recorded across multiple substrates, whereas less frequent taxa are represented by more substrate- or locality-specific records.

Sampling completeness was relatively high, but the inventory was not exhaustive. Coverage values above 0.90 indicate that common and frequently detected taxa were well represented. Chao1 estimates, together with the presence of singleton and doubleton taxa, suggest that additional sampling would probably reveal further rare or sporadically fruiting taxa. The record-based rarefaction, Chao1 and coverage results are therefore best read as inventory-standardisation diagnostics. They support comparison of occurrence-record structure among reserves, but do not define a closed list of taxa for the Knyszyn Forest.

Within the present survey, reserve-level similarity suggests a shared regional myxobiota combined with local habitat differentiation. Jałówka and Krzemianka were most similar in presence–absence comparisons, whereas Las Cieliczański showed somewhat lower similarity to the other two reserves. This pattern is consistent with protected lowland forests. The same broad substrate groups occur across the reserves, but their quantity, decay stage, moisture regime and forest-habitat context differ locally. Such variation can influence which taxa become detectable during field surveys or develop in moist-chamber cultures.

The field and moist-chamber components were strongly complementary. Field surveys documented taxa fruiting naturally in situ, including conspicuous species on logs, bark, litter and other substrates. Moist-chamber cultures extended detection to taxa present on collected substrates as spores, resting stages or other propagules capable of producing identifiable sporocarps under laboratory conditions [5]. The incomplete overlap between the two methods shows that either approach alone would have yielded a narrower picture of the recorded myxobiota. The association between acquisition method and substrate class further indicates that field surveys and moist-chamber cultures sampled different parts of the substrate spectrum.

Substrate structure was one of the clearest ecological patterns in the dataset. Lignicolous, corticolous and foliicolous records dominated the inventory, in agreement with the broader importance of dead wood, bark and other structurally heterogeneous substrates in forest slime mould studies [6,62,63]. These substrates retain moisture, support microbial prey and provide protected surfaces for trophic stages and sporocarp formation. The results identify dead wood and bark as central substrates in the studied reserves, while records from litter, twigs, herbaceous remains, bryophyte-associated material and ground organic matter broaden the documented microhabitat range.

Tree-species patterns should be interpreted in relation to both substrate availability and substrate properties. Quercus robur produced the highest number of records and taxa, while several other common deciduous and coniferous trees also supplied important sampling surfaces. Their contribution is likely linked to local abundance, bark and wood structure, decay stage and sampling opportunity. The pH measurements provide an additional substrate descriptor. Values were generally acidic to weakly acidic, with stronger variation among substrate classes than among reserves. These values refer to moist-chamber soaking water and cannot be treated as direct field measurements of soil, bark or wood pH.

4.3. Habitat and Taxonomy

The habitat descriptors used in the dataset place the records within the forest structure of the reserves. Fresh mixed broadleaved forest sites, Tilio-Carpinetum and natural habitat code 9170 were especially well represented, while 91E0 and 91D0 also contained numerous records and taxa [20]. These records indicate that oak–hornbeam, riparian, alder and bog-woodland-related habitats all contributed to the documented slime mould diversity. The habitat pattern is therefore not restricted to one forest type, although broadleaved forest habitats formed an important part of the record set.

The ecological setting of the three reserves is consistent with the considerable richness recorded in these protected areas. Krzemianka includes spring-fed forest–wetland habitats, Jałówka represents a heterogeneous lowland mixed-forest and wetland-spring system, and Las Cieliczański includes oak–hornbeam forests, mixed coniferous forests, alder carrs and several Natura 2000 habitat types [17,18,19]. For slime moulds, such habitat diversity creates shaded, humid and substrate-rich microsites in close proximity. For the present inventory, continuity of dead organic matter, moisture-buffered substrates and varied decay stages probably contributed strongly to record detection.

From a conservation perspective, the results support retaining diverse dead organic matter in protected forest habitats. Dead wood and bark were the main documented substrates, but the broader substrate spectrum shows that fine woody debris, litter, bryophyte-associated material and herbaceous remains also contribute to forest slime mould diversity. These microhabitats are often overlooked in conventional biodiversity assessments, yet they provide the physical and microbial conditions required by trophic stages and sporocarp-forming taxa.

The taxonomic value of the inventory is strengthened by morphology-based documentation, photographic plates and voucher material. This is particularly important for records with national or regional novelty status and for taxa rarely reported in Poland. At the same time, the treatment of the Lycogala epidendrum and Trichia botrytis complexes shows that some material is better handled as operational taxa when the available characters do not allow secure assignment to segregate species [64,65]. This approach keeps the inventory comparable and transparent without forcing uncertain species-level identifications.

4.4. Limitations and Future Work

The study was designed as a biodiversity inventory, and its results should be interpreted within that framework. The route-based field component was not a probabilistic sampling design, and sampling effort, substrate availability and substrate unit size were not fully standardised. Record counts therefore describe occurrence frequency in the dataset, not population size, density or true dominance.

Seasonality and detectability are also important for interpreting the records. Field surveys were conducted from June to November 2025, while moist-chamber cultures extended detection into laboratory conditions. Sporocarp formation in slime moulds is short-lived and depends on moisture, substrate condition, light exposure and microclimate. A taxon not observed during fieldwork may still be present in a reserve, and a taxon detected in culture reflects its capacity to develop under the incubation conditions used. Field and culture records therefore provide complementary evidence of slime mould occurrence.

The environmental variables should also be interpreted within clear boundaries. pH primarily describes the moist-chamber subset, elevation varied only within a limited lowland range, and station-based meteorological data cannot represent under-canopy humidity or substrate-level moisture. In particular, soaking-water pH integrates solutes released during laboratory immersion and may differ from the pH of bark or wood microsites under field moisture and temperature conditions. These limits restrict causal ecological inference, while the dataset remains useful as a substrate-linked inventory. The current data are strongest for documenting taxonomic diversity, substrate occurrence and reserve-level patterns; targeted environmental sampling would be needed to test ecological mechanisms more directly.

Future work should extend reserve coverage within the Knyszyn Forest and include repeated seasonal sampling with more balanced substrate representation. Substrate-level moisture measurements, systematic pH sampling across both field and culture material, and targeted molecular confirmation of difficult taxa, species complexes and national or regional first records would strengthen ecological and taxonomic interpretation. This inventory provides a baseline for that work.

5. Conclusions

The study shows that the Knyszyn Forest still contains a substantially underdocumented component of Polish myxobiota. Even a focused inventory of three protected reserves revealed diverse slime mould records across several forest habitat contexts, indicating that broader sampling is likely to reveal many additional taxa.

The study also shows that forest microhabitat structure is central to documenting this diversity. Dead wood and bark formed the main substrate basis of the inventory, while records from litter, twigs, bryophyte-associated substrates and other dead organic matter indicate that slime mould diversity in the Knyszyn Forest depends on a broad range of humid, shaded and decomposition-related microsites.

The records of Paradiacheopsis solitaria, Macbrideola rutilipedata and Licea operculata as first records for Poland, with these three included among the 14 first records for north-eastern Poland, show that regional inventories can still substantially change the known distribution of Eumycetozoa in Poland. These findings support further targeted surveys in the Knyszyn Forest, especially in substrate-rich reserves and under-sampled forest habitats. Further standardized, repeated and seasonally balanced surveys will probably reveal additional taxa and provide a stronger basis for ecological comparisons among reserves.

Appendix A.1. Amaurochaetaceae

Appendix A.1.1. Amaurochaete atra (Alb. & Schwein.) Rostaf., Śluzowce (Mycetozoa), Monografia, Pamiętnik Towarzystwa Nauk Ścisłych w Paryżu 5: 211 (1874) [66]

Description: Aethalia pulvinate to effused, first dark-purple (Figure A1A), black when mature, 2.0–7.0 cm in diameter and ca. 1.5 cm high, with black spore mass. Pseudocapillitium rigid and irregular, three-dimensional, composed of vesicle-like to tubular elements, partly with pale margins and ornamented similarly to the spores. Spores dark in transmitted light, warted to spinulose, not conspicuously reticulate, ca. 10.2–11.3 µm in diameter (Figure A1B,C).

Habitat: Recorded exclusively by field collection, mainly on dead wood of Alnus glutinosa and on living bark of Picea abies, with an additional record from dead wood of Betula pendula. The species occurred in Ribeso nigri-Alnetum, Sphagno girgensohnii-Piceetum, and Serratulo-Pinetum communities and Natura 2000 habitats 91D0, 9170, and 91E0.

Appendix A.1.2. Comatricha elegans (Racib.) G. Lister, Guide to the British Mycetozoa Exhibited in the Department of Botany, British Museum (Natural History), ed. 3: 31 (1909) [67]

Description: Sporocarps stalked, scattered, dark-brown, 1.1–1.8 mm high; sporothecae spherical, 0.25–0.42 mm diam. (Figure A1D). Stalk black, slender, 0.75–1.35 mm long, deep dark brown by transmitted light, showing interwoven fibres. Peridium fugacious. Columella short, reaching from the base to approximately 20% of the sporothecal height and splitting into numerous branches. Capillitium moderately dense, arising from the tip of the columella, quite wavy, chiefly dichotomously branched above and ending freely, dark brown by transmitted light (Figure A1E,F). Spores brown in mass, pale brown by transmitted light, covered with fine warts, 8.2–9.9 µm diam. (Figure A1G).

Habitat: Recorded only in moist-chamber cultures, on dead wood of Quercus robur and on dead bark of Carpinus betulus. Both records are from Tilio-Carpinetum forest community, corresponding to Natura 2000 habitat 9170.

Appendix A.1.3. Comatricha nigra (Pers. ex J.F. Gmel.) J. Schrot., in Cohn, Kryptogamen-Flora von Schlesien 3(1): 118 (1885) [68]

Description: Sporocarps stalked, dark brown to blackish, usually 2.5–3.7 mm high; sporothecae globose to ovoid, 0.35–0.55 mm in diameter (Figure A1H). Stalk black, shining, 1.6–3.1 mm long, usually exceeding half the total height. Columella extending nearly to the sporothecal apex and passing into the capillitium (Figure A1I). Capillitium dense, brown, arising along the columella, with slightly thickened terminal portions. Spores brown, finely verrucose, 8.6–9.5 µm in diameter (Figure A1J,K).

Figure A1. Amaurochaete atra (A–C): (A) Immature dark-purple aethalia; (B) Spores; (C) Detail of warted to spinulose, non-reticulate spores. Comatricha elegans (D–G): (D) Stalked sporocarp with spherical sporotheca; (E) Short columella splitting into numerous branches; (F) Brown capillitium with spore mass; (G) Detail of finely warted spores. Comatricha nigra (H–K): (H) Stalked sporocarp with globose to ovoid sporotheca; (I) Columella extending nearly to the sporothecal apex and passing into the capillitium; (J,K) Brown capillitium with finely verrucose spores. Scale bars: (A) = 25 mm; (B,F,J,K) = 10 µm; (C,G) = 5 µm; (D,I) = 0.5 mm; (E) = 0.25 mm; (H) = 1 mm.

Figure A1. Amaurochaete atra (A–C): (A) Immature dark-purple aethalia; (B) Spores; (C) Detail of warted to spinulose, non-reticulate spores. Comatricha elegans (D–G): (D) Stalked sporocarp with spherical sporotheca; (E) Short columella splitting into numerous branches; (F) Brown capillitium with spore mass; (G) Detail of finely warted spores. Comatricha nigra (H–K): (H) Stalked sporocarp with globose to ovoid sporotheca; (I) Columella extending nearly to the sporothecal apex and passing into the capillitium; (J,K) Brown capillitium with finely verrucose spores. Scale bars: (A) = 25 mm; (B,F,J,K) = 10 µm; (C,G) = 5 µm; (D,I) = 0.5 mm; (E) = 0.25 mm; (H) = 1 mm.

Habitat: Recorded predominantly in moist-chamber cultures, mainly on dead wood of Quercus robur, Betula pendula, and Alnus glutinosa, and also on bark of Carpinus betulus and Picea abies; one field record was from herbaceous litter. Most records were from Tilio-Carpinetum or other forest habitats and Natura 2000 habitats 9170, 91E0, and 91D0, with an additional record from Serratulo-Pinetum.

Appendix A.1.4. Comatricha pulchella (C. Bab.) Rostaf., Śluzowce, Monografia, Dodatek: 27 (1876) [69]

Description: Sporocarps stalked, discrete, brown, usually arising from a small hypothallus, 0.9–1.45 mm high; sporothecae broadly ellipsoid to ovoid, sometimes slightly fusiform, 0.3–0.5 mm in diameter and 0.5–0.9 mm long. Stalk black, short, 0.38–0.55 mm long, usually less than half the total height. Columella tapering upward, ending below the apex and passing abruptly into a dense brown capillitium with anastomosing branches and few free ends. Spores reddish brown, minutely warted, 6.8–8.4 µm in diameter.

Habitat: Recorded only in moist-chamber cultures, on fallen leaves of Betula pendula and Quercus robur, and on dead wood of Betula pendula. The records were from Tilio-Carpinetum and related forest habitats and Natura 2000 habitats 9170 and 91E0.

Appendix A.1.5. Comatricha rigida (Brândză) G. Moreno & A. Castillo, Boletín de la Sociedad Micológica de Madrid 47: 4 (2023) [70]

Description: Sporocarps stalked, solitary or in small groups, globose, dark brown, up to 0.8–1.0 mm high (Figure A2A). Sporothecae globose, ca. 0.35 mm diam. Stalk 0.5–0.6 mm high, expanded at the base, with rust-brown fibres; basal stalk fibres intertwined. Columella reaching about 15–25% of the sporotheca. Capillitium sparse, rigid, open, formed by few thick branches, branching toward the apex and ending by dichotomous division (Figure A2B,C). Spores globose, 8.8–9.6 µm diam., brown, pale brown with a purplish tint in transmitted light (Figure A2D,E).

Habitat: Recorded only in moist-chamber culture, on dead bark of Betula pendula in Tilio-Carpinetum forest community, corresponding to Natura 2000 habitat 9170.

Appendix A.1.6. Enerthenema papillatum (Pers.) Rostaf., Śluzowce (Mycetozoa), Monografia, Dodatek: 28 (1876) [69]

Description: Sporocarps stalked, dark brown to blackish, ca. 1.1–1.5 mm high, with a black fibrous stalk 0.5–0.8 mm long (Figure A2F). Sporothecae globose to ovoid, 0.5–0.7 mm diam.; peridium fugacious, persisting only as minute iridescent remnants. The apex with an umbilicate disc (Figure A2H). Columella black, reaching about the middle of the sporotheca and bearing a dense, thin, sinuous capillitium with numerous free ends (Figure A2G). Spores brown in mass, finely and densely warted with slightly darker verrucae, 9.9–11.4 µm diam. (Figure A2I).

Habitat: Recorded by both moist-chamber culture and field collection, predominantly from moist-chamber cultures, on living bark and dead wood. It occurred most often on bark of Quercus robur, with additional records from other broadleaved and coniferous substrates. The species was found mainly in Tilio-Carpinetum and Serratulo-Pinetum communities and Natura 2000 habitats chiefly 9170, with 91D0 and 91E0 also recorded.

Appendix A.1.7. Paradiacheopsis solitaria (Nann.-Bremek.) Nann.-Bremek., De Nederlandse Myxomyceten: 232 (1975) [71]

Description: Sporocarps distinct, stalked, solitary, deep-dark brown, 0.7 mm high; sporothecae globose, ca. 0.25 mm diam. (Figure A2J). Stalk glossy black, tapering upward, ca. 0.45 mm long. Peridium evanescent, sometimes remaining as a narrow collar. Columella dark, extending into the lower third to half of the sporotheca, then dividing into a rigid, sparsely branched capillitium (Figure A2K,L). Spores dark brown in mass, warted but not spinose, mostly 15.4–16.5 µm diam. (Figure A2M).

Habitat: Recorded in moist-chamber cultures on living bark of Betula pendula, Quercus robur, and Carpinus betulus in Tilio-Carpinetum forests and Natura 2000 habitats 9170 and 91D0.

Figure A2. Comatricha rigida (A–E): (A) Stalked, globose sporocarp; (B) Capillitium formed by few thick branches; (C) Capillitial endings with dichotomous division; (D) Spores; (E) Detail of spores. Enerthenema papillatum (F–I): (F) Stalked sporocarp; (G) Black columella bearing dense, thin, sinuous capillitium with numerous free ends; (H) Umbilicate apical disc on sporotheca; (I) Finely and densely warted spores. Paradiacheopsis solitaria (J–M): (J) Stalked sporocarp; (K) Columella dividing into a rigid, sparsely branched capillitium; (L) Branched capillitium with spores; (M) Warted spores. Scale bars: (A,F,G) = 0.5 mm; (B,H,J,K) = 0.25 mm; (C–E,I,M) = 10 µm; (L) = 20 µm.

Figure A2. Comatricha rigida (A–E): (A) Stalked, globose sporocarp; (B) Capillitium formed by few thick branches; (C) Capillitial endings with dichotomous division; (D) Spores; (E) Detail of spores. Enerthenema papillatum (F–I): (F) Stalked sporocarp; (G) Black columella bearing dense, thin, sinuous capillitium with numerous free ends; (H) Umbilicate apical disc on sporotheca; (I) Finely and densely warted spores. Paradiacheopsis solitaria (J–M): (J) Stalked sporocarp; (K) Columella dividing into a rigid, sparsely branched capillitium; (L) Branched capillitium with spores; (M) Warted spores. Scale bars: (A,F,G) = 0.5 mm; (B,H,J,K) = 0.25 mm; (C–E,I,M) = 10 µm; (L) = 20 µm.

Appendix A.1.8. Stemonitopsis amoena (Nann.-Bremek.) Nann.-Bremek., De Nederlandse Myxomyceten: 205 (1975) [71]

Description: Sporocarps solitary or grouped, stalked, cylindrical, erect, brown, 2.4–3.2 mm tall; sporothecae 1.7–2.3 × 0.25–0.35 mm, rounded at end (Figure A3A). Hypothallus common, silvery, net-structured near the stalk; stalk black, 0.6–0.9 mm long. Peridium fugacious. Columella black, reaching the apex. Capillitium brown, arising throughout the columella, ca. 2.5–3.5 µm wide, forming an irregular, partly interrupted surface net. Spores brown in mass, pale brown by transmitted light, 7.2–8.5 µm diam., reticulate, with spines connected by ridges (Figure A3B,C).

Habitat: Recorded only in moist-chamber cultures, on dead wood of Pinus sylvestris in Serratulo-Pinetum and Natura 2000 habitat 91D0.

Appendix A.1.9. Stemonitopsis gracilis (G. Lister) Nann.-Bremek., De Nederlandse Myxomyceten: 210 (1975) [71]

Description: Sporocarps grouped, stalked, cylindrical, rounded at both ends, brown to dark reddish brown, 1.8–2.4 mm high (Figure A3D). Stalk black, hollow, ca. 0.6–0.7 mm long, arising from a thin membranous hypothallus. Peridium fugacious and soon disappearing. Columella black, continuous with the stalk, reaching almost the apex of the sporotheca (Figure A3F). Capillitium dense, arising throughout the columella, with a small-meshed inner net and an almost complete delicate surface net (Figure A3E). Spores pale in transmitted light, finely warted, 5.3–6.6 µm diam. (Figure A3G,H).

Habitat: Recorded only in moist-chamber cultures on dead bark of Quercus robur and dead wood of Betula pendula and Picea abies. Records were associated with Tilio-Carpinetum and Serratulo-Pinetum communities and Natura 2000 habitat 9170.

Appendix A.1.10. Stemonitopsis hyperopta (Meyl.) Nann.-Bremek., Nederlandse Myxomyceten: 206 (1975) [71]

Description: Sporocarps stalked, loosely grouped, cylindrical, dark violet-brown, usually 2.2–3.3 mm high; sporothecae ca. 2.0–2.7 × 0.3–0.4 mm (Figure A3I,J). Stalks black, 0.7–1 mm long, continuing into a columella that reaches or nearly reaches the apex (Figure A3K). Peridium fugacious. Capillitium delicate, ca. 5 µm broad, with a fragmentary surface net and numerous free ends. Spores pale brown in transmitted light, 5.2–6.1 µm diam., ornamented with a fine reticulum of ridges, distinct only under oil immersion, with small circular meshes from which larger meshes arise (Figure A3L,M).

Habitat: Recorded both in the field and in moist-chamber culture, on dead wood. The records were from Tilio-Carpinetum and Serratulo-Pinetum, with Picea abies recorded as a substrate in culture.

Appendix A.1.11. Stemonitopsis typhina (F.H. Wigg.) Nann.-Bremek., De Nederlandse Myxomyceten: 209 (1975) [71]

Description: Sporocarps stalked, solitary or in small groups, cylindrical, erect, rounded at both ends, brown when the peridium is absent, silvery with peridium (Figure A3N). Sporocarps 2.0–3.2 mm; sporothecae 1.5–2.2 × 0.4–0.6 mm. Stalk glossy black, 0.5–1.3 mm long. Peridium evanescent, sometimes originally silvery, without persistent remnants in the examined material. Columella black, reaching or almost reaching the apex (Figure A3P). Capillitium arising from the entire columella, threads ca. 2–3 µm wide, forming a mostly complete surface net (Figure A3O). Spores brown in mass, pale brown-orange or brown-violet by transmitted light, 5.7–6.7 µm diam., finely warted, with distinct groups of darker warts (Figure A3Q,R).

Figure A3. Stemonitopsis amoena (A–C): (A) Stalked cylindrical sporocarps; (B) Spores; (C) Detail of reticulate spores with spines connected by ridges. Stemonitopsis gracilis (D–H): (D) Grouped stalked sporocarps; (E) Sporocarp showing dense capillitium arising throughout the columella; (F) Columella reaching almost the apex of the sporotheca; (G) Spores; (H) Detail of finely warted spores. Stemonitopsis hyperopta (I–M): (I) Stalked cylindrical sporocarps; (J) Microscopic view of a stalked sporocarp; (K) Columella nearly reaching the apex; (L) Spores; (M) Detail of spores with a fine reticulum of ridges. Stemonitopsis typhina (N–R): (N) Stalked cylindrical sporocarps; (O) Capillitium arising from the entire columella and forming a mostly complete surface net; (P) Columella nearly reaching the apex; (Q) Spores; (R) Detail of finely warted spores with darker wart groups. Scale bars: (A,D,E,I,J,N) = 1 mm; (O) = 0.5 mm; (F,K,P) = 100 µm; (B,G,L,Q) = 10 µm; (C,H,M,R) = 5 µm.

Figure A3. Stemonitopsis amoena (A–C): (A) Stalked cylindrical sporocarps; (B) Spores; (C) Detail of reticulate spores with spines connected by ridges. Stemonitopsis gracilis (D–H): (D) Grouped stalked sporocarps; (E) Sporocarp showing dense capillitium arising throughout the columella; (F) Columella reaching almost the apex of the sporotheca; (G) Spores; (H) Detail of finely warted spores. Stemonitopsis hyperopta (I–M): (I) Stalked cylindrical sporocarps; (J) Microscopic view of a stalked sporocarp; (K) Columella nearly reaching the apex; (L) Spores; (M) Detail of spores with a fine reticulum of ridges. Stemonitopsis typhina (N–R): (N) Stalked cylindrical sporocarps; (O) Capillitium arising from the entire columella and forming a mostly complete surface net; (P) Columella nearly reaching the apex; (Q) Spores; (R) Detail of finely warted spores with darker wart groups. Scale bars: (A,D,E,I,J,N) = 1 mm; (O) = 0.5 mm; (F,K,P) = 100 µm; (B,G,L,Q) = 10 µm; (C,H,M,R) = 5 µm.

Habitat: Recorded mainly in moist-chamber cultures, with additional field collections on dead wood and leaf litter. The species occurred predominantly on dead wood, especially of Quercus robur, with additional records from other woody substrates. Records were associated with Tilio-Carpinetum and Fraxino-Alnetum communities and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.2. Arcyriaceae

Appendix A.2.1. Arcyria cinerea (Bull.) Pers., Synopsis Methodica Fungorum 1: 184 (1801) [72]

Description: Sporocarps stalked, solitary to densely crowded, conical to cylindrical or ovoid, whitish, grey to beige or ochraceous, 1.1–3.2 mm tall; sporothecae slightly expanding (Figure A4A). Hypothallus translucent. Stalk 0.7–1.1 mm long, wrinkled, uniform or darker. Peridium fugacious except for a shallow calyculus. Capillitium little elastic, reticulate, attached to the calyculus, threads 2.5–4.2 µm wide, ornamented with fine spines or warts, without spiral bands (Figure A4B,C). Spores light grey in mass, nearly colourless by transmitted light, 6.3–8.1 µm diam., very finely warted with groups of larger warts (Figure A4D).

Habitat: Recorded mainly from moist-chamber cultures, but also collected directly in the field, on a broad range of dead plant substrates. It occurred most often on dead wood and dead bark, with additional records from twigs and litter. The species was found in various forest communities, particularly Tilio-Carpinetum and Fraxino-Alnetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.2.2. Arcyria denudata (L.) Wettst., Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 35(Abh.): 535 (1886) [73]

Description: Sporocarps stalked, usually densely crowded, short-cylindrical, bright red/scarlet, becoming rust-brown with age, 1.7–2.6 mm tall; closed sporothecae 0.4–0.6 mm diam. (Figure A4E). Stalk dark reddish brown, longitudinally striate, 0.5–1 mm long, containing spore-like cysts. Peridium fugacious above, persistent below as a shallow, sharply margined calyculus with reticulate inner surface. Capillitium elastic but brittle, erect, firmly fused to the calyculus, threads 2.7–3.8 µm wide, ornamented with rings, half-rings, warts and ridges (Figure A4F,G). Spores red-brown in mass, pale reddish by transmitted light, 6.3–7.6 µm diam., finely warted with groups of larger warts (Figure A4H).

Habitat: Recorded mainly from moist-chamber cultures, with additional field collections from leaf litter. The species occurred chiefly on dead wood of Quercus robur, Alnus glutinosa, and Betula spp., also on fallen leaves of Carpinus betulus and dead bark of Picea abies and Pinus sylvestris. Records came from several forest communities, especially Tilio-Carpinetum and Fraxino-Alnetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.2.3. Arcyria marginoundulata Nann.-Bremek. & Y. Yamam., Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, Series C 86(2): 218 (1983) [74]

Description: Sporocarps scattered, stalked, 0.55–0.92 mm high; sporothecae globose, 0.25–0.34 mm diam., whitish grey (Figure A4I–K). Stalk 0.4–0.6 mm long, slender, pale above and yellow-brown to rusty brown below. Peridium fugacious, persisting as a small calyculus. Capillitium elastic, reticulate, very brittle, threads 1.7–2.4 µm diam., densely spiny externally (Figure A4L,M). Spores globose, hyaline by transmitted light, 6.6–7.8 µm diam., irregularly warted (Figure A4N).

Habitat: Recorded exclusively in field collections on fallen female catkins of Alnus glutinosa. Occurrences were associated mainly with Fraxino-Alnetum, with an additional record from Ribeso nigri-Alnetum and Natura 2000 habitats 91E0 and 91D0.

Appendix A.2.4. Arcyria minuta Buchet, in Patouillard, Contribution ’a l”etude des Champignons de Madagascar, M’emoires de l’Acad’emie Malgache 6: 42 (1927) [75]

Description: Sporocarps solitary, stalked, short-cylindrical, distinctly salmon-coloured, 0.8 mm high; sporotheca 0.26 mm diam., fading pale beige with age (Figure A4O). Stalk short, 0.3 mm long, orange-brown. Peridium fugacious, remaining as a shallow, basal calyculus. Capillitium reticulate (Figure A4P,Q), rather firmly attached to the calyculus, threads 2.8–3.8 µm diam., strongly ornamented with blunt teeth and warts. Spores pale, globose, 7.2–8.1 µm diam., finely warted.

Figure A4. Arcyria cinerea (A–D): (A) Stalked sporocarps; (B) Spore mass with capillitium; (C) Capillitial threads with fine spines or warts; (D) Spores with fine warts and groups of larger warts. Arcyria denudata (E–H): (E) Mature rust-brown sporocarps; (F) Capillitium; (G) Capillitial threads ornamented with rings, half-rings, warts and ridges; (H) Finely warted spores with groups of larger warts. Arcyria marginoundulata (I–N): (I) Stalked sporocarp; (J,K) Globose sporothecae with small calyculus; (L) Spore mass with capillitium; (M) Reticulate capillitium with spiny threads; (N) Irregularly warted spores. Arcyria minuta (O–Q): (O) Salmon-coloured sporocarp; (P,Q) Reticulate capillitium with visible spore ornamentation. Scale bars: (A,E,O) = 1 mm; (I) = 0.25 mm; (J,K) = 0.1 mm; (B–D,F–H,L,N,P,Q) = 10 µm; (M) = 2.5 µm.

Figure A4. Arcyria cinerea (A–D): (A) Stalked sporocarps; (B) Spore mass with capillitium; (C) Capillitial threads with fine spines or warts; (D) Spores with fine warts and groups of larger warts. Arcyria denudata (E–H): (E) Mature rust-brown sporocarps; (F) Capillitium; (G) Capillitial threads ornamented with rings, half-rings, warts and ridges; (H) Finely warted spores with groups of larger warts. Arcyria marginoundulata (I–N): (I) Stalked sporocarp; (J,K) Globose sporothecae with small calyculus; (L) Spore mass with capillitium; (M) Reticulate capillitium with spiny threads; (N) Irregularly warted spores. Arcyria minuta (O–Q): (O) Salmon-coloured sporocarp; (P,Q) Reticulate capillitium with visible spore ornamentation. Scale bars: (A,E,O) = 1 mm; (I) = 0.25 mm; (J,K) = 0.1 mm; (B–D,F–H,L,N,P,Q) = 10 µm; (M) = 2.5 µm.

Habitat: Recorded in moist-chamber culture on dead wood of Quercus robur. The single record came from Fraxino-Alnetum and Natura 2000 habitats 91E0 and 9170.

Appendix A.3. Ceratiomyxaceae

Appendix A.3.1. Ceratiomyxa fruticulosa (O.F. Müll.) T. Macbr., The North American Slime-Moulds: 18 (1899) [76]

Description: Fruiting bodies extensive, forming crowded white to yellowish, watery colonies; fructifications often erect, 2.9–5.5 mm high and ca. 0.3 mm wide at the base (Figure A5A). The fertile surface bears spores externally on tiny stalklets (Figure A5B). Spores white in mass, colourless or faintly yellowish by transmitted light, smooth, ellipsoid, 9.9–11.8 × 6.5–8.1 µm, with granular contents (Figure A5D).

Habitat: Recorded predominantly from moist-chamber cultures and less frequently by field collection, chiefly on dead wood and occasionally on dead bark. The species occurred on a broad range of substrates, including both coniferous and broadleaved trees. It was found in various forest communities, especially Tilio-Carpinetum and Fraxino-Alnetum and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.3.2. Ceratiomyxa porioides (Alb. & Schwein.) J. Schröt., in Engler & Prantl, Die Natürlichen Pflanzenfamilien 1(1): 16 (1889) [77]

Description: Fruiting bodies poroid, forming flat, sheet-like, whitish to pale yellowish fructifications; pores 0.15–0.32 mm diameter (Figure A5C). The fructification is soft and watery, with the fertile surface bearing spores externally on tiny stalklets as in Ceratiomyxa fruticulosa. Spores white in mass, colourless to faintly yellowish by transmitted light, smooth, ellipsoid 10.2–11.9 × 6.6–7.9 µm. The taxon is distinguished morphologically chiefly by its flat poroid habit.

Habitat: Recorded exclusively by field collection, on dead wood of Alnus glutinosa, Pinus sylvestris, and Picea abies. The species was found in several forest communities Tilio-Carpinetum, Serratulo-Pinetum, Fraxino-Alnetum, and Sphagno girgensohnii-Piceetum and Natura 2000 habitats 9170, 91D0, and 91E0.

Figure A5. Ceratiomyxa fruticulosa (A,B,D): (A) Crowded erect fruiting bodies; (B) Fertile surface with spores borne externally on tiny stalklets; (D) Smooth ellipsoid spores. Ceratiomyxa porioides (C): (C) Flat poroid fruiting bodies. Scale bars: (A,B) = 5 mm; (C) = 1 mm; (D) = 10 µm.

Figure A5. Ceratiomyxa fruticulosa (A,B,D): (A) Crowded erect fruiting bodies; (B) Fertile surface with spores borne externally on tiny stalklets; (D) Smooth ellipsoid spores. Ceratiomyxa porioides (C): (C) Flat poroid fruiting bodies. Scale bars: (A,B) = 5 mm; (C) = 1 mm; (D) = 10 µm.

Appendix A.4. Clastodermataceae

Clastoderma debaryanum A. Blytt, Botanische Zeitung 38: 343 (1880) [78]

Description: Sporocarps stalked, brown, usually 0.9–1.3 mm high, with globose sporothecae 0.20–0.31 mm diam. (Figure A6A). Stalk tapering upward, dark below and translucent yellow-brown above, characteristically with a yellow or reddish swelling in the upper half (Figure A6B). Capillitium dichotomously branched, narrowing outward, with plate expansions forming a partial surface net (Figure A6C). Spores light rust-brown in mass, pale grey or light-brown by transmitted light, angular, finely warted or faintly reticulate, 9.1–10.5 µm diameter (Figure A6D).

Habitat: Recorded only in moist-chamber cultures, on dead bark of Carpinus betulus and dead wood of Quercus robur. The records were associated with forest habitats and Natura 2000 habitats 9170 and 91E0.

Appendix A.5. Cribrariaceae

Appendix A.5.1. Cribraria argillacea (Pers. ex J.F. Gmel.) Pers., Neues Magazin für Die Botanik in Ihrem Ganzen Umfange 1: 89 (1794) [79]

Description: Sporocarps crowded, in large groups, short-stalked, brown to olive-ochre, 0.75–1.2 mm high; sporothecae globose, 0.57–0.76 mm diam. Hypothallus brown, stalk dark, nearly black, longitudinally wrinkled. Peridium persistent chiefly below as a deep, delimited calyculus, the upper part forming an irregular reticulum with indistinct nodes and granular ribs. Spores pale ochre-brown in mass, nearly colourless to pale brown by transmitted light, finely warted, 6.2–7.7 µm diam.

Habitat: Recorded predominantly in moist-chamber cultures, with one field collection, mainly on dead wood and occasionally on dead bark. Substrates included Quercus robur, Pinus sylvestris, Picea abies, and Alnus glutinosa, in Tilio-Carpinetum, Serratulo-Pinetum, and Ribeso nigri-Alnetum communities and Natura 2000 habitat 9170.

Appendix A.5.2. Cribraria cancellata (Batsch) Nann.-Bremek., De Nederlandse Myxomyceten: 92 (1975) [71]

Description: Sporocarps stalked, 1.5–2.4 mm high, with violet-brown depressed-globose sporothecae 0.38–0.55 mm diameter, often nodding and umbilicate at the apex (Figure A6E). Stalk 0.95–1.90 mm long, pinkish or reddish at the apex, dark red-brown. Calyculus low or sometimes absent; when present glossy and membranous, reaching at most one-fourth of the sporotheca. Peridial net arising from the stalk apex, densely granular, composed of numerous (ca. 40) mostly parallel ribs connected by delicate threads (Figure A6F,G). Granules dark purplish brown, concentrated on the ribs. Spores reddish to purplish brown in mass, pale brown by transmitted light, verrucose, 5.3–6.4 µm diam. (Figure A6H).

Habitat: Recorded by both moist-chamber culture and field collection, consistently on dead wood. The species occurred most often on Picea abies and Betula pendula, and also on Pinus sylvestris, chiefly in Tilio-Carpinetum and Serratulo-Pinetum communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.5.3. Cribraria languescens Rex, Proceedings of the Academy of Natural Sciences of Philadelphia 43(2): 394 (1891) [80]

Description: Sporocarps solitary, long-stalked, 2.6–3.2 mm high, with small globose sporothecae 0.25–0.35 mm diam., orange-brown (Figure A6I). Stalk very long and slender, about 2.2–3.0 mm long, dark brown, sometimes twisted. Calyculus well developed, ribbed, occupying about one-third to half of the sporotheca (Figure A6J,K); peridial net with thickened nodes, thin connecting threads, and few free ends. Spores light orange-brown in mass, pale by transmitted light, finely warted or verrucose, 7.3–8.0 µm diam., sometimes with yellow-green inclusions (Figure A6L,M).

Habitat: Recorded in moist-chamber culture on dead wood of Pinus sylvestris in Serratulo-Pinetum.

Figure A6. Clastoderma debaryanum (A–D): (A) Small group of stalked sporocarps; (B) Sporocarp with yellow or reddish swelling in the upper half of the stalk; (C) Dichotomously branched capillitium with plate expansions forming a partial surface net; (D) Capillitium and angular, finely warted or faintly reticulate spores. Cribraria cancellata (E–H): (E) Stalked sporocarps with violet-brown, nodding sporothecae; (F) Sporotheca with peridial net arising from the stalk apex and numerous mostly parallel ribs; (G) Peridial ribs and spores; (H) Detail of verrucose spores. Cribraria languescens (I–M): (I) Long-stalked sporocarp; (J,K) Globose sporothecae with well-developed, ribbed calyculus; (L,M) Peridial net and finely warted or verrucose spores. Cribraria microcarpa (N–R): (N) Long-stalked sporocarp; (O) Sporotheca with regular net and dark, thickened nodes; (P) Regular peridial net; (Q) Net with slender connecting threads and spores; (R) Detail of finely warted spores. Scale bars: (A,I) = 1 mm; (B,N) = 0.5 mm; (C,F,P) = 0.25 mm; (E) = 2.5 mm; (J,K,O) = 0.1 mm; (D,G,L,M,Q,R) = 10 µm; (H) = 5 µm.

Figure A6. Clastoderma debaryanum (A–D): (A) Small group of stalked sporocarps; (B) Sporocarp with yellow or reddish swelling in the upper half of the stalk; (C) Dichotomously branched capillitium with plate expansions forming a partial surface net; (D) Capillitium and angular, finely warted or faintly reticulate spores. Cribraria cancellata (E–H): (E) Stalked sporocarps with violet-brown, nodding sporothecae; (F) Sporotheca with peridial net arising from the stalk apex and numerous mostly parallel ribs; (G) Peridial ribs and spores; (H) Detail of verrucose spores. Cribraria languescens (I–M): (I) Long-stalked sporocarp; (J,K) Globose sporothecae with well-developed, ribbed calyculus; (L,M) Peridial net and finely warted or verrucose spores. Cribraria microcarpa (N–R): (N) Long-stalked sporocarp; (O) Sporotheca with regular net and dark, thickened nodes; (P) Regular peridial net; (Q) Net with slender connecting threads and spores; (R) Detail of finely warted spores. Scale bars: (A,I) = 1 mm; (B,N) = 0.5 mm; (C,F,P) = 0.25 mm; (E) = 2.5 mm; (J,K,O) = 0.1 mm; (D,G,L,M,Q,R) = 10 µm; (H) = 5 µm.

Appendix A.5.4. Cribraria macrocarpa Schrad., Nova Genera Plantarum, Pars Prima cum Tabulis Aeneis Coloratis (1797) [81]

Description: Sporocarps crowded, erect, ochre-brown, usually large, 1.6–3.0 mm high, with sporothecae 0.7–1.2 mm diam. Stalk dark brown arising from dark hypothallus. Calyculus deep, dark, strongly radially ribbed, persistent to about half the sporotheca and gradually passing into an irregular, dark peridial net of broad bands, with free arching ends and no true nodes. Spores ochre-brown in mass, pale brown by transmitted light, verrucose, 6.3–8.4 µm diam.

Habitat: Recorded both in the field and in moist-chamber culture on dead wood of Pinus sylvestris in Serratulo-Pinetum.

Appendix A.5.5. Cribraria microcarpa (Schrad.) Pers., Synopsis Methodica Fungorum 1: 190 (1801) [72]

Description: Sporocarps minute, long-stalked, globose and often nodding, brown to rust-brown, 1.3–2.9 mm high (Figure A6N). Sporothecae 0.16–0.29 mm diameter. Stalk conspicuously slender, dark orange-brown, longitudinally wrinkled and often twisted, arising from a small discoid hypothallus. Calyculus rudimentary or reduced to a small star-shaped basal disc, passing into a regular net with dark, thickened nodes and slender connecting threads (Figure A6O–Q). Spores dark-orange to ochre in mass, light reddish brown by transmitted light, finely warted, 6.6–7.5 µm diam. (Figure A6R).

Habitat: Recorded predominantly in moist-chamber cultures, with several field collections, mainly on dead wood and occasionally on living bark or leaf litter. Dead wood of Betula pendula was the most frequent substrate, with additional records from other broadleaved and coniferous trees. The species occurred chiefly in Tilio-Carpinetum, with records also from other forest communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.5.6. Cribraria oregana H.C. Gilbert, in Peck & H.C. Gilbert, American Journal of Botany 19(2): 142 (1932) [82]

Description: Sporocarps stalked, loosely grouped, rust-brown, 0.7–1.1 mm high, with sporothecae 0.35–0.56 mm diam. (Figure A7A). Stalk dark brown, longitudinally fibrous, 0.45–0.60 mm long. Calyculus distinct, ribbed, not perforate, persistent for about one-quarter of the sporotheca, with a rather abrupt to ragged transition into the net (Figure A7B). Peridial net well developed, with fairly regular meshes and flat, irregular nodes; free ends absent (Figure A7C,D). Spores orange-brown in mass, pale yellowish-olivaceous in transmitted light, finely warted, 6.8–7.8 µm diam. (Figure A7E).

Habitat: Recorded only from moist-chamber cultures, on dead bark of Carpinus betulus and dead wood of Quercus robur and Alnus glutinosa. The records were associated with Tilio-Carpinetum and several habitat contexts and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.5.7. Cribraria rufa (Roth) Rostaf., Pamiętnik Towarzystwa Nauk Ścisłych w Paryżu 6(1): 232 (1875) [66]

Description: Sporocarps gregarious, stalked, erect, globose, orange to orange-brown, 1.5–2.5 mm high, sporothecae 0.5–0.8 mm diam. Stalk dark red-brown, longitudinally striate. Calyculus sharply delimited, radially ribbed, persistent for one-third to one-half of the sporotheca, with margin mostly perforate and passing into the net. Peridial net persistent, coarse, composed of flat bands with scarcely expanded mesh angles and essentially no true nodes. Spores orange-brown in mass, light brown by transmitted light, finely warted, 6.2–8.1 µm diam.

Habitat: Recorded both in the field and in moist-chamber cultures, mainly on strongly decayed dead wood, with one field record from woody debris. Substrates included Pinus sylvestris, Quercus robur, and Picea abies, occurring in Tilio-Carpinetum and Serratulo-Pinetum communities and Natura 2000 habitats 9170, 91D0, and 91E0 recorded for part of the material).

Appendix A.5.8. Cribraria violacea Rex, Proceedings of the Academy of Natural Sciences of Philadelphia 43: 393 (1891) [80]

Description: Sporocarps stalked, in small groups, erect, broadly ovoid, dark violet, 0.8–1.2 mm high, with sporothecae 0.22–0.29 mm diam. (Figure A7F). Stalk dark violet, longitudinally striate, about 0.8–1 mm long. Calyculus prominent, persistent for about half to 2/3 of the sporotheca, with a lobed, partly perforate margin. Peridial net irregular, with large, flat to slightly thickened, conspicuously expanded nodes (Figure A7G,H). Spores dark violet in mass, lilac by transmitted light, finely warted, 7.3–8.4 µm diam. (Figure A7I).

Habitat: Recorded exclusively from moist-chamber cultures on dead bark. Substrates included Betula pubescens, Quercus robur, and Pinus sylvestris, in Tilio-Carpinetum and Serratulo-Pinetum communities and Natura 2000 habitats 9170 and 91D0.

Figure A7. Cribraria oregana (A–E): (A) Stalked rust-brown sporocarps; (B) Sporocarp with distinct ribbed calyculus; (C) Well-developed peridial net with fairly regular meshes and flat nodes; (D) Peridial net meshes with spores; (E) Finely warted spores. Cribraria violacea (F–I): (F) Dark violet stalked sporocarps; (G) Sporotheca with prominent calyculus and irregular peridial net; (H) Peridial net with spores; (I) Finely warted spores. Cribraria vulgaris (J–N): (J) Globose stalked sporocarp; (K) Sporotheca under the microscope; (L) Sharply delimited ribbed calyculus; (M) Spore mass with fragments of the peridial net; (N) Finely warted spores. Scale bars: (A,J) = 0.25 mm; (B,C,G,K,L) = 0.1 mm; (D) = 20 µm; (E,H,I,M,N) = 10 µm; (F) = 1 mm.

Figure A7. Cribraria oregana (A–E): (A) Stalked rust-brown sporocarps; (B) Sporocarp with distinct ribbed calyculus; (C) Well-developed peridial net with fairly regular meshes and flat nodes; (D) Peridial net meshes with spores; (E) Finely warted spores. Cribraria violacea (F–I): (F) Dark violet stalked sporocarps; (G) Sporotheca with prominent calyculus and irregular peridial net; (H) Peridial net with spores; (I) Finely warted spores. Cribraria vulgaris (J–N): (J) Globose stalked sporocarp; (K) Sporotheca under the microscope; (L) Sharply delimited ribbed calyculus; (M) Spore mass with fragments of the peridial net; (N) Finely warted spores. Scale bars: (A,J) = 0.25 mm; (B,C,G,K,L) = 0.1 mm; (D) = 20 µm; (E,H,I,M,N) = 10 µm; (F) = 1 mm.

Appendix A.5.9. Cribraria vulgaris Schrad., Nova Genera Plantarum, Pars Prima cum Tabulis Aeneis Coloratis: 6 (1797) [81]

Description: Sporocarps scattered, stalked, globose, usually slightly nodding, brown to ochraceous, 0.8–1.3 mm high, with sporothecae 0.42–0.58 mm diam. (Figure A7J,K). Stalk dark brown, longitudinally striate, about 0.6–0.94 mm long. Calyculus always present, sharply delimited, not perforate, strongly radially ribbed and finely transversely wrinkled, persistent for about one-third of the sporotheca (Figure A7L). Peridial net persistent, with flat, variable, often expanded and confluent nodes, and many spine-like free ends (Figure A7M). Spores ochre in mass, light brown by transmitted light, finely warted, 5.9–7.1 µm diam. (Figure A7N).

Habitat: Recorded both in moist-chamber cultures and by field collection, consistently on dead wood. The species occurred most often on dead wood of Pinus sylvestris and Quercus robur, also on Picea abies and Betula pendula, in Tilio-Carpinetum, Serratulo-Pinetum, and Querco-Piceetum communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.6. Dictydiaethaliaceae

Dictydiaethalium plumbeum (Schumach.) Rostaf. ex Lister, A Monograph of the Mycetozoa: 157 (1894) [83]

Description: Pseudoaethalia irregular, thread-like to effused, 0.5–4 cm diam. and about 1 mm thick, yellow-brown, composed of palisade-like sporocarps forming a tessellated surface. Apical peridial plates persistent, lid-like, slightly convex, mostly 100–160 µm diam.; lateral walls evanescent except for persistent margins. Pseudocapillitium present, thread-like, brown. Spores dark brown in mass, pale yellow brown by transmitted light, globose, finely spinulose, 10.2–11.7 µm diam.

Habitat: Recorded by field collection on dead wood. The available records came from Fraxino-Alnetum and Tilio-Carpinetum communities and Natura 2000 habitats 91E0 and 9170.

Appendix A.7. Didymiaceae

Appendix A.7.1. Diderma saundersii (Berk. & Broome ex Massee) E. Sheld., Minnesota Botanical Studies 1: 477 (1895) [84]

Description: Fructifications plasmodiocarpous, depressed and very thin (ca. 0.15 mm) (Figure A8A), with a double wall; outer peridium calcareous, fragile and not porcelain-like, inner layer membranous. Capillitium built of thin threads (Figure A8B), sometimes branching, colourless to brown. Spores brown, globose, about 9.7–10.8 µm in diameter (Figure A8C).

Habitat: Recorded from a moist-chamber culture on dead bark of Picea abies. The only record was from Serratulo-Pinetum.

Appendix A.7.2. Diderma testaceum (Schrad.) Pers., Synopsis Methodica Fungorum 1: 167 (1801) [72]

Description: Sporocarps sessile, crowded, non-nivicolous, depressed and flat-pulvinate, 0.65–0.97 mm diam. and about 0.25–0.35 mm high, without plasmodiocarps (Figure A8D). Peridium distinctly double; outer layer brittle, smooth, egg shell-like, beige. Inner layer grey, slightly iridescent, not firmly united with the outer layer. A basal thickening or depressed columella is present (Figure A8E,F). Capillitium brown, branched, 1–1.5 µm diam. (Figure A8G). Spores brown, nearly globose, finely verrucose, without a pale equatorial band, 7.8–8.8 µm diam. (Figure A8H).

Habitat: Recorded mainly from moist-chamber cultures on fallen leaves of Betula pendula and Quercus robur, and on dead wood of Alnus glutinosa; one field collection was from mosses. The records were associated with Tilio-Carpinetum and Fraxino-Alnetum communities and Natura 2000 habitats 9170 and 91E0.

Appendix A.7.3. Didymium melanospermum (Pers.) T. Macbr., The North American Slime-Moulds, ed. 1: 88 (1899) [76]

Description: Sporocarps solitary or in small groups, stalked, 0.7–1.1 mm high; sporothecae depressed-globose, broader than high, light grey, deeply umbilicate at the stalk insertion, 0.4–0.6 mm diam. Stalk black, 0.4–0.65 mm long (Figure A8I). Peridium simple, densely covered with whitish lime crystals. Columella hemispherical, lime-filled within. Capillitium brown, flexuous, sparsely branched, 2–3 µm diam. Spores deep dark brown in mass, dark brown by transmitted light, verrucose, 10.2–12.2 µm diam.

Habitat: Recorded only from moist-chamber cultures, on dead wood of Quercus robur and fallen leaves of Betula pendula. The records came from Fraxino-Alnetum and Tilio-Carpinetum forests and Natura 2000 habitats 91E0 and 9170.

Appendix A.7.4. Didymium minus (Lister) Morgan, Journal of the Cincinnati Society of Natural History 16(4): 145 (1894) [85]

Description: Fruiting bodies in small groups, stalked, mostly erect, 0.88–1.25 mm high; sporothecae snow-white, globose, umbilicate at the base, 0.4–0.6 mm in diameter (Figure A8J). Stalk brown to dark brown, opaque, non-calcareous, 0.4–0.6 mm high, sunk into the basal depression (Figure A8K). Peridium densely dusted with loose stellate lime crystals, not forming a smooth crust. Columella or pseudocolumella distinct. Capillitium pale brown-yellow, delicate, dense, with free spinose ends. Spores brown, densely warted, 8.1–9.8 µm in diameter (Figure A8L).

Habitat: Recorded mainly from moist-chamber cultures, with one field collection from leaf litter. The species occurred predominantly on fallen leaves, especially of Alnus glutinosa and Carpinus betulus, mostly in Tilio-Carpinetum forests, with an additional record from Sphagno girgensohnii-Piceetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.7.5. Didymium nigripes (Link) Fr., Systema Mycologicum 3(1): 119 (1829) [86]

Description: Fruiting bodies stalked, solitary, erect, 0.9–1.4 mm high; sporothecae white to grey, globose, slightly umbilicate at the stalk apex, 0.4–0.8 mm in diameter. Stalk non-calcareous, blackish, paler above, 0.4–0.9 mm high, longitudinally fibrous. Peridium simple, externally white from stellate lime crystals. Columella black-brown. Capillitium arising from the columella, thin, brown, sparingly branched. Spores brown, verrucose with darker wart groups, 8.3–10.3 µm in diameter.

Habitat: Recorded only from a moist-chamber culture, on twigs of Pinus sylvestris. The single record came from Serratulo-Pinetum.

Appendix A.7.6. Didymium spongiosum (Leyss.) J.M. García-Martín, J.C. Zamora & Lado, Persoonia 51: 103 (2023) [87]

Description: Fruiting body a sessile aethalium, usually about 18–35 mm in extent and ca. 20 mm high, composed of crowded, branched tubes (Figure A8M). Aethalia white grey coloured. Peridium delicate, membranous, scantily limy. Capillitium dark brown, branched, up to 4 µm wide, with pointed colourless ends. Spores dark brown in mass, wood-brown in transmitted light, warted to spinulose, 12.9–15.0 µm in diameter (Figure A8N,O).

Habitat: Recorded exclusively by field collection, on leaf litter, dead wood, and plant stems. The species occurred in Tilio-Carpinetum, Fraxino-Alnetum, and Ribeso nigri-Alnetum communities and Natura 2000 habitats 91E0 and 9170.

Figure A8. Diderma saundersii (A–C): (A) Thin plasmodiocarpous fructifications; (B) Thin capillitial threads with spores; (C) Spores. Diderma testaceum (D–H): (D) Crowded depressed sporocarps; (E,F) Sporocarps with double peridium and depressed columella; (G) Branched capillitium with spores; (H) Finely verrucose spores. Didymium melanospermum (I): (I) Stalked sporocarp with depressed-globose sporotheca and black stalk. Didymium minus (J–L): (J) Grouped snow-white sporocarps; (K) Sporocarp with stalk sunk into the basal depression; (L) Capillitium with densely warted spores. Didymium spongiosum (M–O): (M) Mature aethalium; (N,O) Warted to spinulose spores. Didymium squamulosum (P,Q): (P) Grey-white sporocarps with brownish discolorations and strongly longitudinally wrinkled stalks; (Q) Verrucose spores. Scale bars: (A,M) = 10 mm; (D–F,I–K,P) = 1 mm; (B,C,G,H,L,N,O,Q) = 10 µm.

Figure A8. Diderma saundersii (A–C): (A) Thin plasmodiocarpous fructifications; (B) Thin capillitial threads with spores; (C) Spores. Diderma testaceum (D–H): (D) Crowded depressed sporocarps; (E,F) Sporocarps with double peridium and depressed columella; (G) Branched capillitium with spores; (H) Finely verrucose spores. Didymium melanospermum (I): (I) Stalked sporocarp with depressed-globose sporotheca and black stalk. Didymium minus (J–L): (J) Grouped snow-white sporocarps; (K) Sporocarp with stalk sunk into the basal depression; (L) Capillitium with densely warted spores. Didymium spongiosum (M–O): (M) Mature aethalium; (N,O) Warted to spinulose spores. Didymium squamulosum (P,Q): (P) Grey-white sporocarps with brownish discolorations and strongly longitudinally wrinkled stalks; (Q) Verrucose spores. Scale bars: (A,M) = 10 mm; (D–F,I–K,P) = 1 mm; (B,C,G,H,L,N,O,Q) = 10 µm.

Appendix A.7.7. Didymium squamulosum (Alb. & Schwein.) Fr. & Palmquist, Symbolae Gasteromycorum ad Illustrandam Floram Svecicam fasc. 3: 19 (1818) [88]

Description: Fruiting bodies stalked, 0.8–1.1 mm high; sporothecae grey-white, slightly flattened, 0.5–0.7 mm in diameter, umbilicate at the stalk apex and often with brownish discolorations (Figure A8P). Hypothallus distinct, forming a basal pad. Stalk calcareous, beige, strongly longitudinally wrinkled, often twisted, 0.5–0.7 mm high. Peridium single, densely dusted with white-grey lime crystals. Columella hemispherical to flattened, pale. Capillitium colourless to brown, simply branched, ca. 1–2 µm wide. Spores brown to dark-brown, verrucose, 10.0–11.7 µm in diameter (Figure A8Q).

Habitat: Recorded both in the field and in moist-chamber cultures, mainly on fallen leaves and dead wood. Substrates included fallen leaves of Betula pendula and Quercus robur, dead wood of Carpinus betulus, and general litter, mostly in Tilio-Carpinetum forests and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.8. Echinosteliaceae

Echinostelium minutum de Bary, in Rostafiński, Śluzowce (Mycetozoa), Monografia, Pamiętnik Towarzystwa Nauk Ścisłych w Paryżu 5(4): 215 (1874) [66]

Description: Fruiting bodies sporocarpic, stalked, grouped, white with a yellowish tint, 0.2–0.4 mm high; sporothecae globose, 40–70 µm in diameter. Peridium evanescent, persisting as a small collar at the stalk apex. Columella hyaline, up to ca. 5 µm long. Capillitium hyaline, delicate, branched, with meshes and free ends. Spores translucent, globose, 6.4–8.5 µm in diameter.

Habitat: Recorded only from moist-chamber cultures, mainly on living bark of Betula pendula and Carpinus betulus, with additional records from fallen leaves of Quercus robur and dead wood of Picea abies. The species occurred in Tilio-Carpinetum and Serratulo-Pinetum and Natura 2000 habitats mainly 9170, with 91D0 and 91E0 also recorded.

Appendix A.9. Hemitrichiaceae

Appendix A.9.1. Hemitrichia clavata (Pers.) Rostaf. in Fuckel, Jahrbücher des Nassauischen Vereins für Naturkunde 27–28: 75 (1873) [89]

Description: Sporocarps stalked, clavate, shining yellow, 1.4–2.2 mm high; sporothecae 0.7–1.2 mm high and 0.6–1.4 mm diam. Stalk 0.5–1 mm long, brown, expanding upward and merging gradually into a deep goblet-like calyculus. Peridium irregularly dehiscent above, lower half persistent. Capillitium elastic, yellow, attached only at the stalk apex, threads 4–7 µm diam., with 3–5 spiral bands and spines. Spores yellow, 7.4–9.3 µm diam., finely reticulate-warted and marginate.

Habitat: Recorded mainly from moist-chamber cultures on dead wood of Quercus robur, with one field record from living bark of the same tree species. The records were associated chiefly with Tilio-Carpinetum and Querco roboris-Pinetum communities and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.9.2. Hemitrichia serpula (Scop.) Rostaf. ex Lister, A Monograph of the Mycetozoa, ed. 2: 64 (1911) [90]

Description: Fructifications plasmodiocarpous, sessile, yellow-brown, forming reticulate networks (Figure A9A), extending over 0.4–2.1 cm; plasmodiocarps 0.30–0.46 mm high and 0.33–0.50 mm thick. Peridium single, yellowish (Figure A9B). Capillitium golden yellow, very elastic, forming continuous threads 5.1–7.2 µm diam., with 3–4 tight spiral bands and short spinose ends (Figure A9C). Spores golden yellow, pale yellow in transmitted light, 10.7–12.9 µm diameter, coarsely reticulate (Figure A9D).

Habitat: Recorded predominantly in moist-chamber cultures, chiefly on dead wood and fallen leaves, especially of Quercus robur, Alnus glutinosa, and Betula pendula; field collections were from litter. The species occurred mainly in Tilio-Carpinetum and Fraxino-Alnetum, with one record from Serratulo-Pinetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.9.3. Heterotrichia insignis (Kalchbr. & Cooke) Yatsiuk, Leontyev & Schnittler, Fungal Systematics and Evolution 15: 111 (2024) [91]

Description: Sporocarps stalked, solitary, erect, salmon-pink, 1.5–1.9 mm high; sporothecae cylindrical, 0.25–0.40 mm diam. (Figure A9E). Stalk reddish, longitudinally wrinkled, 0.4–0.55 mm long, with spore-like cysts. Peridium fugacious, leaving a shallow calyculus (Figure A9F). Capillitium inelastic, firmly attached to the calyculus, threads 2–3 µm diam., pale yellowish, with spiral half-rings and spines (Figure A9G). Spores pink in mass, colourless by transmitted light, 6.6–8.1 µm diam., sparsely finely warted (Figure A9H).

Habitat: Recorded only in moist-chamber cultures from dead wood of Quercus robur and fallen leaves of Betula pendula in Tilio-Carpinetum oak-hornbeam forest and Natura 2000 habitat 9170.

Appendix A.9.4. Heterotrichia obvelata (Oeder) Yatsiuk, Leontyev & Schnittler, in Yatsiuk et al., Fungal Systematics and Evolution 15: 111 (2025) [91]

Description: Sporocarps shortly stalked, densely grouped, yellow to creamy-yellow without red tones, elongate cylindrical, 2.0–3.0 mm high; sporothecae 0.3–0.5 mm diam. (Figure A9I). Stalk minute, 0.15–0.25 mm long, yellow. Calyculus about 1–1.5 mm deep, ribbed, the sporocarp detaching readily. Capillitium very elastic, free and easily detached, spinose, threads 2.8–4.0 µm diam. (Figure A9J). Spores nearly translucent, pale yellowish, 7.2–8.5 µm diam., finely warted with scattered larger warts (Figure A9K).

Habitat: Recorded mainly in moist-chamber cultures, with one field collection, predominantly on dead wood. The species occurred on dead wood of Quercus robur and Betula pendula, and also on Pinus sylvestris and Alnus glutinosa, in Tilio-Carpinetum, Serratulo-Pinetum, and Fraxino-Alnetum communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.9.5. Heterotrichia oerstedii (Rostaf.) Yatsiuk, Leontyev & Schnittler, Fungal Systematics and Evolution 15: 112 (2024) [91]

Description: Sporocarps stalked, reddish brown, with a fugacious peridium and a sharply delimited calyculus. The capillitium is loosely attached to the calyculus and often separates in mature sporocarps. Threads readily fragment and bear long, fine spines. Spores 7.0–7.9 µm in diameter.

Habitat: Recorded only in moist-chamber cultures from dead wood of Betula pendula, Alnus glutinosa, and Picea abies. The records were associated with forest habitats Querco-Piceetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.9.6. Heterotrichia pomiformis (Leers) Yatsiuk, Leontyev & Schnittler, Fungal Systematics and Evolution 15: 112 (2024) [91]

Description: Sporocarps scattered or solitary, stalked, olive-brown to light ochraceous-yellow, globose, 0.7–1.1 mm high, the sporotheca 0.3–0.5 mm in diameter and retaining a broadly ovoid form after peridial loss (Figure A9L,M). Stalk 0.35–0.55 mm long, pale to brownish, approximately equalling the sporotheca. Peridium fugacious, persistent only as a small, shallow, calyculus strongly attached to the capillitium. Capillitium elastic, widely expanded, light yellow, with threads 3.2–5.0 µm wide, densely warted to nodulose, without evident spiral ridges (Figure A9N). Spores light yellowish, nearly translucent in transmitted light, finely warted, 7.8–9.0 µm in diameter (Figure A9O).

Habitat: Recorded both in the field and in moist-chamber cultures, mainly on dead wood and dead bark. The most frequent substrates were Alnus glutinosa, Quercus robur, and Carpinus betulus, with additional coniferous substrates also recorded. The species occurred chiefly in Tilio-Carpinetum and Fraxino-Alnetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Figure A9. Hemitrichia serpula (A–D): (A) Yellow-brown reticulate plasmodiocarps; (B) Plasmodiocarps with single yellowish peridium; (C) Golden-yellow capillitium with visible spiral bands; (D) Coarsely reticulate spores. Heterotrichia insignis (E–H): (E) Salmon-pink stalked sporocarp; (F) Shallow calyculus and spores; (G) Capillitium with spiral half-rings and spines; (H) Sparsely finely warted spores. Heterotrichia obvelata (I–K): (I) Densely grouped sporocarps with ribbed calyculi; (J) Spinose capillitium and spores; (K) Finely warted spores with scattered larger warts. Heterotrichia pomiformis (L–O): (L,M) Ochraceous-yellow globose sporocarps; (N) Warted to nodulose capillitium and spores; (O) Finely warted spores. Scale bars: (A,B) = 1 mm; (E,I) = 0.5 mm; (L,M) = 0.1 mm; (C,G) = 5 µm; (D,F,H,J,K,N,O) = 10 µm.

Figure A9. Hemitrichia serpula (A–D): (A) Yellow-brown reticulate plasmodiocarps; (B) Plasmodiocarps with single yellowish peridium; (C) Golden-yellow capillitium with visible spiral bands; (D) Coarsely reticulate spores. Heterotrichia insignis (E–H): (E) Salmon-pink stalked sporocarp; (F) Shallow calyculus and spores; (G) Capillitium with spiral half-rings and spines; (H) Sparsely finely warted spores. Heterotrichia obvelata (I–K): (I) Densely grouped sporocarps with ribbed calyculi; (J) Spinose capillitium and spores; (K) Finely warted spores with scattered larger warts. Heterotrichia pomiformis (L–O): (L,M) Ochraceous-yellow globose sporocarps; (N) Warted to nodulose capillitium and spores; (O) Finely warted spores. Scale bars: (A,B) = 1 mm; (E,I) = 0.5 mm; (L,M) = 0.1 mm; (C,G) = 5 µm; (D,F,H,J,K,N,O) = 10 µm.

Appendix A.10. Lamprodermataceae

Appendix A.10.1. Collaria arcyrionema (Rostaf.) Nann.-Bremek. ex Lado, Ruizia 9: 26 (1991) [92]

Description: Sporocarps stalked, 1.0–1.7 mm high, with globose sporothecae 0.4–0.6 mm in diameter, silver when peridiate and dark brown after peridial loss (Figure A10A). Stalk 0.6–1.0 mm long, slender, glossy black, broadened at the base. Columella reaching about one-third to one-half of the sporotheca and apically branched (Figure A10C). Capillitium dense, brown, wavy, and finely roughened (Figure A10D). Spores dark brown in mass, finely warted, 8.0–9.0 µm in diameter (Figure A10E).

Habitat: Recorded both in the field and in moist-chamber cultures, mainly on dead wood of Quercus robur, Carpinus betulus, and Betula pendula, with an additional record from living bark of Betula pendula. It occurred chiefly in Tilio-Carpinetum oak-hornbeam forest and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.10.2. Lamproderma scintillans (Berk. & Broome) Morgan, Journal of the Cincinnati Society of Natural History 16(4): 131 (1894) [85]

Description: Sporocarps scattered, stalked; sporotheca globose, 0.4–0.6 mm diam., iridescent, with blue, violet and bronze colours; total height 1–1.6 mm. Stalk slender, lightly broadened at base, 0.65–1 mm long, usually longer than sporotheca, black, indistinctly longitudinally striate. Peridium delicate, persistent but falling away in large pieces (Figure A10B). Columella cylindrical reaching about half the sporotheca. Capillitium rigid, arising mostly from the upper part of the columella, often fork-branched, connected by cross-links; threads dark brown, with many finely pointed colourless ends. Spores brown in mass, light grey-brown by transmitted light, pale, with dark, evenly distributed warts, 7.2–9.0 µm diam. (Figure A10F).

Habitat: Recorded only in moist-chamber cultures from fallen leaves of Quercus robur and Alnus glutinosa. The records were associated with forest habitats Serratulo-Pinetum and Natura 2000 habitats 9170 and 91E0.

Appendix A.11. Liceaceae

Appendix A.11.1. Licea kleistobolus G.W. Martin, Mycologia 34(6): 702 (1942) [93]

Description: Sporocarps sessile, minute, in small groups, flattened and disciform, 0.12–0.20 mm in diameter, dark brown. Dehiscence circumscissile, by a preformed, strongly shining, sunken operculum (Figure A10G). Peridium thin; the lid is yellow-brown in transmitted light and bears hollow tubules on the inner surface. Spore mass light-ochraceous in mass, nearly colourless in transmitted light, 9.1–10.2 µm in diameter, ornamented with fine dark warts (Figure A10J).

Habitat: Recorded from a moist-chamber culture on dead bark of Quercus robur in Tilio-Carpinetum oak-hornbeam forest habitat and Natura 2000 habitat 9170.

Appendix A.11.2. Licea minima Fr., Systema Mycologicum 3(1): 199 (1829) [86]

Description: Sporocarps sessile, scattered, hemispherical, 0.3–0.45 mm diam., nearly black. Peridium layered, dark, with raised ridges, dehiscing along the ridges into persistent polygonal plates (Figure A10H). Capillitium absent. Spore yellowish-olivaceous in mass, citrine-olivaceous by transmitted light, evenly and densely minutely verrucose, 10.6–12.5 µm diam. (Figure A10K,L).

Habitat: Recorded mainly from moist-chamber cultures, with one field collection from ground litter. Substrates included dead bark of Quercus robur and Betula pendula, dead wood of Pinus sylvestris, and ground litter, in Tilio-Carpinetum, Querco roboris-Pinetum, and Serratulo-Pinetum communities, including oak-hornbeam forest habitat and Natura 2000 habitat 9170.

Figure A10. Collaria arcyrionema (A,C–E): (A) Dark brown globose sporocarp after peridial loss; (C) Apically branched columella reaching about half of the sporotheca; (D) Capillitium with spores; (E) Detail of finely warted spores. Lamproderma scintillans (B,F): (B) Iridescent globose sporotheca with peridium falling away in large pieces; (F) Warted spores. Licea kleistobolus (G,J): (G) Disciform sporocarps with strongly shining, sunken opercula; (J) Spores with fine dark warts. Licea minima (H,K,L): (H) Nearly black sporocarps with raised peridial ridges and polygonal plates; (K,L) Densely minutely verrucose spores. Licea operculata (I,M): (I) Stalked dark sporocarp; (M) Spores showing a smooth surface. Scale bars: (A,B) = 0.5 mm; (C,G–I) = 0.1 mm; (D–F,J–M) = 10 µm.

Figure A10. Collaria arcyrionema (A,C–E): (A) Dark brown globose sporocarp after peridial loss; (C) Apically branched columella reaching about half of the sporotheca; (D) Capillitium with spores; (E) Detail of finely warted spores. Lamproderma scintillans (B,F): (B) Iridescent globose sporotheca with peridium falling away in large pieces; (F) Warted spores. Licea kleistobolus (G,J): (G) Disciform sporocarps with strongly shining, sunken opercula; (J) Spores with fine dark warts. Licea minima (H,K,L): (H) Nearly black sporocarps with raised peridial ridges and polygonal plates; (K,L) Densely minutely verrucose spores. Licea operculata (I,M): (I) Stalked dark sporocarp; (M) Spores showing a smooth surface. Scale bars: (A,B) = 0.5 mm; (C,G–I) = 0.1 mm; (D–F,J–M) = 10 µm.

Appendix A.11.3. Licea operculata (Wingate) G.W. Martin, Mycologia 34(6): 702 (1942) [93]

Description: Sporocarps stalked, solitary, subglobose, dark olive-brown to nearly black, 0.6–0.8 mm high; sporothecae 0.15–0.25 mm diam. (Figure A10I). Stalk slender, dull black, wrinkled, opaque, 0.6–0.7 mm long. Peridium finely punctate, with included particles. Lid shining, with smooth margin. Spore mass light yellow; almost colourless by transmitted light, smooth, 9.5–12.0 (14.5) µm diam. (Figure A10M).

Habitat: Recorded both in the field and from moist-chamber cultures, chiefly on dead bark. Substrate records included dead bark of Quercus robur and Betula pendula, with plant-community records from Tilio-Carpinetum, including oak-hornbeam forest habitat and Natura 2000 habitat 9170.

Appendix A.12. Physaraceae

Appendix A.12.1. Angioridium sinuosum (Bull.) Grev., Scottish Cryptogamic Flora 6(62): pl. 310 (1827) [94]

Description: Fruiting bodies plasmodiocarpous, elongate, often laterally compressed, grey-white from white lime, usually 0.28–0.40 mm wide and 0.6–3 mm long (Figure A11A,B). Peridium double, with two separated layers, opening by a preformed longitudinal slit whose margins spread widely. Columella absent. Capillitium a network of hyaline threads with grey-white, lime nodes. Spore mass dark brown; spores brown in transmitted light, very densely and finely warted, 9.4–11.2 µm diam. (Figure A11C–E).

Habitat: Recorded both in moist-chamber cultures and in the field, on fallen leaves of Betula pendula and Quercus robur, as well as on mosses and small plant detritus. Most records were associated with Tilio-Carpinetum oak-hornbeam forest and Natura 2000 habitat 9170, with additional records from other forest habitats and Natura 2000 habitats 91D0 and 91E0.

Appendix A.12.2. Badhamia utricularis (Bull.) Berk., Proceedings of the Linnean Society of London 2: 199 (1852) [95]

Description: Fructifications pendent from the substrate and forming extensive colonies, sporocarps clustered, the sporothecae globose, ca. 0.5–1.0 mm diam. Columella absent. Capillitium attached to the peridium, forming a wide-meshed network of flat, ribbon-like lime-filled tubes. Spore mass black; spores free or in small clusters, brown by transmitted light, evenly warted, 11.0–13.2 µm diam.

Habitat: Recorded in the field on dead wood of Quercus robur. The occurrence was associated with Tilio-Carpinetum and Natura 2000 habitat 9170.

Appendix A.12.3. Craterium concinnum Rex, Proceedings of the Academy of Natural Sciences of Philadelphia 45(3): 370 (1893) [96]

Description: Sporocarps stalked, solitary, funnel-shaped, 0.6–0.9 mm high; sporothecae 0.3–0.4 mm diam., opening by a distinctly delimited preformed lid (Figure A11H). Upper sporangium dark woody brown and without lime coating, lid separated by a paler band; persistent cup with a thickened raised rim. Stalk dark brown, ca. 0.15–0.3 mm long. Columella absent. Capillitium with small yellow-brown lime nodes. Spores dark brown, brown by transmitted light, strongly warted, 9.6–10.7 µm diam. (Figure A11I).

Habitat: Recorded only in a moist-chamber culture, on dead bark of Alnus glutinosa. The record came from Fraxino-Alnetum forest and Natura 2000 habitats 91E0, 9170, and 91D0.

Appendix A.12.4. Craterium minutum (Leers) Fr., Systema Mycologicum 3(1): 151 (1829) [86]

Description: Sporocarps stalked, goblet-shaped, 0.9–1.3 mm high, sporothecae 0.4–0.65 mm diam., opening by a sharply delimited, preformed lid that is hemispherical (Figure A11F). Sporothecae pale brown below, dark woody brown above, the limeless lid separated by a pale band and bordered by a thickened raised rim; stalk dark brown, ca. 0.3–0.6 mm long. Peridium double; capillitium with pale lime nodes. Spores dark brown in mass, brown in transmitted light, strongly warted, 8.8–10.5 µm diam. (Figure A11G).

Habitat: Recorded only in moist-chamber cultures, on dead wood and fallen leaves of Quercus robur, and on fallen leaves of Betula pendula. The records were from Tilio-Carpinetum and related forest habitats and Natura 2000 habitats 9170 and 91E0.

Appendix A.12.5. Fuligo leviderma H. Neubert, Nowotny & K. Baumann, Die Myxomyceten Deutschlands und des Angrenzenden Alpenraumes Unter Besonderer Berücksichtigung Österreichs, Band 2: Physarales 2: 211 (1995) [30]

Description: Aethalia solitary, hemispherical, 20–30 mm across and 12–18 mm thick, cinnamon-brown (Figure A11N). Hypothallus smooth, concolorous with the cortex near the base. Cortex smooth, persistent, ca. 60 µm thick, golden-brown in transmitted light. Capillitium of hyaline threads ca. 1 µm wide. Spores dark brown in mass, brown in transmitted light, densely verruculose, 6.5–8.0 µm diam. (Figure A11O).

Habitat: Recorded only by field collection, predominantly on dead wood of Quercus robur, with additional records from dead bark of Quercus robur and dead wood of Pinus sylvestris. Occurrences were associated with Tilio-Carpinetum, Querco roboris-Pinetum and Serratulo-Pinetum communities and Natura 2000 habitat 9170.

Appendix A.12.6. Fuligo septica (L.) F.H. Wigg., Primitiae Florae Holsaticae: 112 (1780) [97]

Description: Aethalia usually solitary, pulvinate to hemispherical, irregular but rounded, varying in size, 16–270 mm, and ca. 15–25 mm high. In the typical expression they are yellow to ochraceous (Figure A11J); where the cortex is lost, the exposed spore mass is black-brown, nodulose through the pseudocapillitium. Hypothallus white. Cortex foamy and crumbly, brittle, yellow to ochraceous, breaking into small flakes and containing lime granules 2.2–3.5 µm diam. Capillitium more or less abundant, composed of hyaline, sparsely branched threads with white lime plates. Spores black in mass, pale brown in transmitted light, round, finely warted, 7.2–9.5 µm diam. (Figure A11M). The species was recorded in three varieties. Var. candida is distinguished by white to cream-coloured aethalia (Figure A11K), white lime in the capillitium and pseudocapillitium. Var. flava has yellow aethalia and yellow lime deposits, with spores usually slightly smaller and consistently spherical. Var. rufa is characterized by pale reddish to dark red-brown aethalia (Figure A11L) and reddish lime deposits; its spores were reported to be mostly smaller, ca. 6.1–7.9 µm diam.

Habitat: Recorded exclusively by field collection, most often on dead wood, with additional records from fallen leaves, living bark, plant surfaces, and ground organic matter. Substrates included mainly Quercus robur, Betula pendula, Alnus glutinosa, Pinus sylvestris, and Picea abies, in various forest communities, especially Tilio-Carpinetum, Fraxino-Alnetum, and Serratulo-Pinetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.12.7. Leocarpus fragilis (Dicks.) Rostaf., Pamiętnik Towarzystwa Nauk Ścisłych w Paryżu 5: 132 (1874) [66]

Description: Sporocarps densely crowded, stalked, 2.2–3.3 mm high, yellow-brown, shining, clavate or cylindric, with rounded apex (Figure A11P). Hypothallus membranous, whitish; stalk flaccid, wrinkled, 0.9–1.3 mm long. Peridium firm, layered, varnish-like externally and brittle. Capillitium duplex, with a coarse limy network interpenetrated by hyaline threads. Spores deep dark brown in mass, wood-brown in transmitted light, distinctly warted, 12.1–14.0 µm diam. (Figure A11Q).

Habitat: Recorded only in field collections, on dead wood, dead bark, leaf litter, and herbaceous litter. Occurrences were mainly associated with Tilio-Carpinetum communities and oak-hornbeam forest habitats and Natura 2000 habitat 9170, with one record also linked to riparian forest habitat and Natura 2000 habitat 91E0.

Figure A11. Angioridium sinuosum (A–E): (A) Elongate plasmodiocarps on plant detritus; (B) Detail of plasmodiocarps; (C) Spores; (D,E) Detail of very densely and finely warted spores. Craterium minutum (F,G): (F) Stalked goblet-shaped sporocarp; (G) Strongly warted spores. Craterium concinnum (H,I): (H) Stalked funnel-shaped sporocarp with raised preformed lid; (I) Strongly warted spores. Fuligo septica (J–M): (J) Yellow to ochraceous aethalium; (K) White to cream-coloured aethalium of var. candida; (L) Pale reddish to dark red-brown aethalium of var. rufa; (M) Finely warted spores with fragments of yellow cortex. Fuligo leviderma (N,O): (N) Cinnamon-brown hemispherical aethalium; (O) Densely verruculose spores. Leocarpus fragilis (P,Q): (P) Densely crowded, yellow-brown shining sporocarps; (Q) Distinctly warted spores. Scale bars: (A,B,F,P) = 1 mm; (C–E,G,I,M) = 10 µm; (H) = 0.5 mm; (J–L) = 10 mm; (N) = 5 mm; (O,Q) = 15 µm.

Figure A11. Angioridium sinuosum (A–E): (A) Elongate plasmodiocarps on plant detritus; (B) Detail of plasmodiocarps; (C) Spores; (D,E) Detail of very densely and finely warted spores. Craterium minutum (F,G): (F) Stalked goblet-shaped sporocarp; (G) Strongly warted spores. Craterium concinnum (H,I): (H) Stalked funnel-shaped sporocarp with raised preformed lid; (I) Strongly warted spores. Fuligo septica (J–M): (J) Yellow to ochraceous aethalium; (K) White to cream-coloured aethalium of var. candida; (L) Pale reddish to dark red-brown aethalium of var. rufa; (M) Finely warted spores with fragments of yellow cortex. Fuligo leviderma (N,O): (N) Cinnamon-brown hemispherical aethalium; (O) Densely verruculose spores. Leocarpus fragilis (P,Q): (P) Densely crowded, yellow-brown shining sporocarps; (Q) Distinctly warted spores. Scale bars: (A,B,F,P) = 1 mm; (C–E,G,I,M) = 10 µm; (H) = 0.5 mm; (J–L) = 10 mm; (N) = 5 mm; (O,Q) = 15 µm.

Appendix A.12.8. Nannengaella globulifera (Bull.) J.M. García-Martín, J.C. Zamora & Lado, Persoonia 51: 103 (2023) [87]

Description: Sporocarps stalked, erect, 0.8–1.3 mm high, sporothecae globose, 0.4–0.6 mm diam., grey-white. Stalk cream-coloured, wrinkled, calcareous, 0.5–0.7 mm long. Peridium simple, thin, membranous, with white to brownish lime scales. Columella short, conical. Capillitium dense, hyaline, with small pale lime nodes. Spores brown in mass, light brown in transmitted light, finely verrucose, 7.5–10.2 µm diam.

Habitat: Recorded in moist-chamber culture on dead wood of Quercus robur in Tilio-Carpinetum forest and Natura 2000 habitat 9170.

Appendix A.12.9. Physarum album (Bull.) Chevall., Flore Générale des Environs de Paris 1: 336 (1826) [98]

Description: Sporocarps gregarious or in small groups, never fused, stalked, very often nodding, silver-white to greyish white, slightly flattened, sometimes globose, 1.1–1.5 mm high; sporothecae 0.5–0.75 mm diam.; stalks 0.6–0.95 mm long, limeless, dark brown below and paler upward, attenuate, wrinkled and curved (Figure A12A,B). Peridium with white-grey lime, splitting into patches. Columella and pseudocolumella absent. Capillitium delicate, lime-poor, with small white nodes. Spores dark brown in mass, brown in transmitted light, densely and finely warted, 7.2–9.3 µm diam. (Figure A12C,D).

Habitat: Recorded predominantly in moist-chamber cultures, with additional field collections, on dead wood, dead bark, twigs, fallen leaves, and fine woody litter. The substrates most often involved Carpinus betulus, Betula pendula, Quercus robur, Pinus sylvestris, and Picea abies, in various forest communities, especially Tilio-Carpinetum, mainly Natura 2000 habitat 9170, with additional records from 91D0 and 91E0.

Appendix A.12.10. Physarum cinereum (Batsch) Pers., Neues Magazin für Die Botanik in Ihrem Ganzen Umfange 1: 89 (1794) [79]

Description: Sporocarps sessile, gregarious, white to grey-white, globose to hemispherical, 0.5–0.8 mm diam. or forming short plasmodiocarps to 1.2 mm long (Figure A12E,F). Peridium simple, fragile, coated with white lime. Columella absent. Capillitium abundant, a reticulate system of short hyaline tubules connecting rounded white lime nodes, usually 20–30 µm diam. (Figure A12G). Spore mass very dark brown; brown in transmitted light, globose, without a pale band, densely warted, 9.9–11.4 µm diam. (Figure A12H).

Habitat: Recorded both in moist-chamber cultures and in the field, on dead wood of Quercus robur, fallen leaves of Betula pendula and Quercus robur, and living herbaceous plants. Occurrences were associated mainly with Tilio-Carpinetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.12.11. Physarum compressum Alb. & Schwein., Conspectus Fungorum in Lusatiae Superioris Agro Niskiensi Crescentium, e Methodo Persooniana: 97 (1805) [99]

Description: Sporocarps shortly stalked or sessile, scattered to crowded, pale grey, usually laterally compressed, 1.1–1.5 mm high; sporothecae reniform to rounded-triangular in side view, about 0.6–0.9 mm broad; stalks short, wrinkled, 0.4–0.7 mm long, whitish to brown according to lime content (Figure A12I). Peridium simple, with white lime scales, opening shell-like. Columella absent. Capillitium abundant, hyaline, with white rounded to irregular lime nodes. Spores black in mass, dark brown by transmitted light, warted with darker groups or band-like zones, 12–14 (15.6) µm diam. (Figure A12J,K).

Habitat: Recorded both in the field and in moist-chamber culture, on leaf litter and on dead wood of Betula pendula. The records were associated with Tilio-Carpinetum communities and Natura 2000 habitat 9170.

Figure A12. Physarum album (A–D): (A) Gregarious nodding sporocarps; (B) Nodding sporocarp with dark brown lower stalk and paler wrinkled upper stalk; (C) Dark brown spore mass; (D) Detail of densely finely warted spores. Physarum cinereum (E–H): (E) Mature globose sporocarps; (F) Short plasmodiocarps; (G) Reticulate capillitium of short hyaline tubules connecting white lime nodes; (H) Detail of densely warted spores. Physarum compressum (I–K): (I) Crowded pale grey, laterally compressed sporocarps; (J) Black spore mass; (K) Detail of warted spores with darker groups or band-like zones. Physarum leucophaeum (L,N,P): (L) Erect grey-white sporocarp; (N) Sporotheca with a slightly darkened base; (P) Detail of densely finely warted spores. Physarum pusillum (M,O,Q): (M) Sporocarp with darker lower stalk and rust-brown sporotheca near the stalk; (O) Sporotheca viewed from below; (Q) Detail of finely warted spores. Physarum viride (R–T): (R) Sulphur-yellow long-stalked sporocarps; (S) Spores with yellowish remnants of lime scales; (T) Detail of finely warted spores. Scale bars: (A,B,E,I,L,M,R) = 0.5 mm; (F) = 0.25 mm; (N,O) = 0.1 mm; (C,G,Q,S,T) = 10 µm; (D) = 2.5 µm; (H,K,P) = 5 µm; (J) = 15 µm.

Figure A12. Physarum album (A–D): (A) Gregarious nodding sporocarps; (B) Nodding sporocarp with dark brown lower stalk and paler wrinkled upper stalk; (C) Dark brown spore mass; (D) Detail of densely finely warted spores. Physarum cinereum (E–H): (E) Mature globose sporocarps; (F) Short plasmodiocarps; (G) Reticulate capillitium of short hyaline tubules connecting white lime nodes; (H) Detail of densely warted spores. Physarum compressum (I–K): (I) Crowded pale grey, laterally compressed sporocarps; (J) Black spore mass; (K) Detail of warted spores with darker groups or band-like zones. Physarum leucophaeum (L,N,P): (L) Erect grey-white sporocarp; (N) Sporotheca with a slightly darkened base; (P) Detail of densely finely warted spores. Physarum pusillum (M,O,Q): (M) Sporocarp with darker lower stalk and rust-brown sporotheca near the stalk; (O) Sporotheca viewed from below; (Q) Detail of finely warted spores. Physarum viride (R–T): (R) Sulphur-yellow long-stalked sporocarps; (S) Spores with yellowish remnants of lime scales; (T) Detail of finely warted spores. Scale bars: (A,B,E,I,L,M,R) = 0.5 mm; (F) = 0.25 mm; (N,O) = 0.1 mm; (C,G,Q,S,T) = 10 µm; (D) = 2.5 µm; (H,K,P) = 5 µm; (J) = 15 µm.

Appendix A.12.12. Physarum leucophaeum Fr. & Palmquist, in Fries & Nordholm, Symbolae Gasteromycorum ad Illustrandam Floram Svecicam 3: 24 (1818) [88]

Description: Sporocarps stalked, erect, grey-white, rarely slightly nodding, 1.1–1.6 mm high, appearing in large groups (Figure A12L). Sporothecae globose with a slightly darkened base, 0.6–1.0 mm diam.; stalks usually about or scarcely exceeding the sporothecal diameter, 0.5–0.8 mm long, dark brown, lime-free and paler apically (Figure A12N). Peridium colourless, irregularly marbled with white lime. Columella short and fugacious. Capillitium rigid, with rounded/irregular white lime nodes. Spores dark brown, densely finely warted, 9.2–10.5 µm diam. (Figure A12P).

Habitat: Recorded exclusively from moist-chamber cultures, on dead wood of Betula pendula and Quercus robur, and on fallen leaves of Carpinus betulus. The species was recorded from Tilio-Carpinetum and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.12.13. Physarum pusillum (Berk. & M.A. Curtis) G. Lister, A Monograph of the Mycetozoa, ed. 2: 64 (1911) [90]

Description: Sporocarps stalked, erect, pale whitish to grey, in small groups, 0.8–1.2 mm high; sporothecae flattened-globose, rust-brown near the stalk, 0.4–0.6 mm diam. (Figure A12M,O). Stalks slender, lime-free, brown and darker below, 0.6–0.8 mm long. Hypothallus brown. Peridium colourless, brownish toward the stalk. Columella absent. Capillitium hyaline, with irregular white lime plates. Spores deep dark brown in mass, lilac-brown or brown by transmitted light, finely warted, 11.2–13.0 µm diam. (Figure A12Q).

Habitat: Recorded in moist-chamber culture from fallen leaves of Quercus robur. The single record was from Tilio-Carpinetum and Natura 2000 habitat 9170.

Appendix A.12.14. Physarum viride (Bull.) Pers., Annalen der Botanik (Usteri) 15: 6 (1795) [100]

Description: Sporocarps long-stalked, mostly nodding, yellow to sulphur-yellow and fading with age, 1.2–1.7 mm high; sporothecae depressed-globose, 0.4–0.6 mm diam.; stalks 0.7–1.2 mm long, dark brown to blackish below, pale near the apex (Figure A12R). Peridium simple, usually limy, covered with yellow to grey-yellow lime scales. Columella absent. Capillitium delicate and dense, yellowish, with small lime nodes. Spores brown, finely warted, without conspicuous larger wart groups, 7.0–8.5 µm diam. (Figure A12S,T).

Habitat: Recorded mainly from moist-chamber cultures, with one field collection from leaf litter. It occurred predominantly on dead wood, especially of Carpinus betulus, but also on dead wood of Picea abies and Pinus sylvestris, and on dead bark of Alnus glutinosa. Records came from Tilio-Carpinetum, Querco-Piceetum, Ribeso nigri-Alnetum, Fraxino-Alnetum, and Serratulo-Pinetum communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.13. Reticulariaceae

Appendix A.13.1. Lycogala epidendrum (L.) Fr. Complex, Systema Mycologicum 3(1): 80 (1829) [86]

Description: Fruiting bodies sessile, aethalioid, in groups, loosely scattered to densely crowded, sometimes mutually compressed, globose to hemispherical, mostly 5–8 mm diam. (Figure A13A). Colour variable, pink to orange or yellow-brown, pale-brown or dark brown; hypothallus pale brown to colourless. Cortex thin and fragile, light beige to dark brown, sparsely to densely covered with concolorous or darker scales. Pseudocapillitium light brown, branched, minutely spinulose or finely warted, 6.5–16.5 µm diam., with rounded, clavate free ends. Spores pale ochraceous in mass, bright yellow or colourless by transmitted light, 6.0–7.3 µm diam., with a fine reticulum, usually incomplete over a small surface area (Figure A13G,H). The examined material is treated as the Lycogala epidendrum complex because recent taxonomic revision has shown that the former aggregate includes multiple segregate species [64]. Habitat: Recorded exclusively in field collections, predominantly on dead wood and dead bark. The species complex occurred on several deciduous and coniferous hosts, most often Pinus sylvestris, Quercus robur, Picea abies, and Alnus glutinosa, with additional records from Betula pendula, Betula pubescens, and Carpinus betulus. Occurrences were distributed across various forest communities, especially Serratulo-Pinetum, Tilio-Carpinetum, Fraxino-Alnetum, and Querco-Piceetum and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.13.2. Reticularia lycoperdon Bull., Herbier de la France 10(109–120): pl. 446, fig. 4 (1790) [101]

Description: Aethalia solitary, sessile, hemispherical, closed, silvery white, later becoming brown, usually 3.5 to 5.5 cm diam. (Figure A13F). Hypothallus white, forming a distinct marginal border; cortex thick, persistent and pale, shining. Pseudocapillitium brown, arising from the base as plates and fraying into dendroid columns of flexuous threads 2.5–8.0 µm diam. (Figure A13I). Spores brown-olivaceous in mass, pale brown by transmitted light, 8.0–9.2 µm diam., with a fine reticulum and warts (Figure A13J).

Habitat: Recorded exclusively by field collection, mainly on dead wood, with additional records from dead bark and dead twigs. It was found most often in Tilio-Carpinetum and Serratulo-Pinetum, with further records from Querco-Piceetum and Natura 2000 habitats 9170, 91D0, and 91E0.

Figure A13. Lycogala epidendrum complex (A–E,G,H): (A) Groups of orange aethalioid fruiting bodies; (B–E) Variation in sporocarp pigmentation, peridial vesicle shape and arrangement, and crystalline, oily, or pigmented vesicle deposits; (G) Spores; (H) Detail of spores showing a fine, partly incomplete reticulum. Reticularia lycoperdon (F,I,J): (F) Immature aethalium; (I) Brown pseudocapillitium and spores; (J) Detail of spores showing fine reticulum and warts. Scale bars: (A) = 10 mm; (B–E) = 1 mm; (F) = 25 mm; (G,I) = 10 µm; (H,J) = 5 µm.

Figure A13. Lycogala epidendrum complex (A–E,G,H): (A) Groups of orange aethalioid fruiting bodies; (B–E) Variation in sporocarp pigmentation, peridial vesicle shape and arrangement, and crystalline, oily, or pigmented vesicle deposits; (G) Spores; (H) Detail of spores showing a fine, partly incomplete reticulum. Reticularia lycoperdon (F,I,J): (F) Immature aethalium; (I) Brown pseudocapillitium and spores; (J) Detail of spores showing fine reticulum and warts. Scale bars: (A) = 10 mm; (B–E) = 1 mm; (F) = 25 mm; (G,I) = 10 µm; (H,J) = 5 µm.

Appendix A.13.3. Tubifera ferruginosa (Batsch) J.F. Gmel., Systema Naturae, ed. 13, 2(2): 1472 (1792) [102]

Description: A pseudoaethalium composed of numerous densely united, sessile sporangia, 15–52 mm diam. Single sporocarps cylindrical, rounded, 3–5 mm high and 0.2–0.35 mm diam., their rounded apices projecting separately at the surface. Hypothallus well developed, pale brown. Peridium thin, persistent, rupturing irregularly from the apex. Pseudocapillitium and capillitium absent. Spores umber-brown in mass, pale reddish brown by transmitted light, 6.3–7.9 µm diam., finely reticulate.

Habitat: Recorded both by field collection and moist-chamber culture, consistently on dead wood. Substrates included dead wood of Pinus sylvestris in Serratulo-Pinetum and Quercus robur in Tilio-Carpinetum and Natura 2000 habitats 9170 and 91D0.

Appendix A.14. Stemonitidaceae

Appendix A.14.1. Macbrideola rutilipedata (H. Marx) G. Moreno, Seraoui, Mar. Mey. & López-Vill., Phytotaxa 613(2): 183 (2023) [103]

Description: Sporocarps stalked, 0.4–0.65 mm high; sporotheca cylindrical to ovoid (Figure A14A,B), with a fugacious peridium. Capillitium sinuous, yellowish brown, arising from the columella (Figure A14C,D). Spores wood-brown in mass, pale brown by transmitted light, 6.2–7.6 µm diam., distinctly spiny (Figure A14E,F).

Habitat: Recorded only by field collection on fallen female catkins of Alnus glutinosa, mainly in Ribeso nigri-Alnetum and also in Fraxino-Alnetum and Natura 2000 habitats 91E0, 9170, and 91D0.

Appendix A.14.2. Stemonitis axifera (Bull.) T. Macbr., The North American Slime-Moulds, ed. 1: 120 (1899) [76]

Description: Sporocarps stalked, tufted, cylindrical, narrowed fusiformly at the base, rust-brown, 6.1 to 12.5 mm high (Figure A14G,H). Sporothecae 0.4–0.6 mm diam., 4.1–8.9 mm high. Stalks tubular and hollow, funnel-expanded at the base, black, 2.5–6.2 mm long, dark brown to black. Columella a continuation of the stalk, extending to the apex of the sporocarp, black, dark brown in transmitted light. Capillitium arising from the entire columella, internally forming a three-dimensional net with 2–3 meshes to the periphery; inner threads 2.5–5 µm thick, with membranous expansions, brown in transmitted light. Surface net with irregular meshes 2.7–12.5 µm diam., threads 0.6–1.3 µm thick, light brown (Figure A14I,J). Spores brown in mass, pale brown in transmitted light, smooth, 5.7–7.2 µm diam. (Figure A14K,L). Stemonitis axifera var. smithii represents a smaller and paler form, with pale ferruginous sporocarps in small tufts, 2.5–5.5 mm high, nearly smooth spores 4.3–5.8 µm diam. (Figure A14M,P,Q). It has a bit denser internal capillitium between the columella and surface net. Small fruiting bodies of typical S. axifera are macroscopically scarcely separable from this variety.

Habitat: Recorded both in the field and in moist-chamber cultures, consistently on dead wood. Moist-chamber records were from dead wood of Quercus robur, Betula pendula, Carpinus betulus, Pinus sylvestris, and Picea abies. The species occurred in Tilio-Carpinetum, Fraxino-Alnetum, and Serratulo-Pinetum communities and Natura 2000 habitats 9170, 91D0, and 91E0.

Appendix A.14.3. Stemonitis flavogenita E. Jahn, Verhandlungen des Botanischen Vereins der Provinz Brandenburg 45: 165 (1904) [104]

Description: Sporocarps stalked, in small tufts, brown to wood-brown, 4.8–6.2 mm high (Figure A14R). Sporothecae cylindrical, rounded apically and slightly tapering basally, ca. 0.3–0.4 mm diam. and 3.5–4.5 mm high. Stalks glossy black, 1.2–1.8 mm long. Columella nearly reaching the apex, often terminating in a membranous discoid to funnel-shaped expansion (Figure A14S). Capillitium stout, with a rigid surface net of irregular polygonal meshes (Figure A14T). Spores brown in mass, light brown by transmitted light, densely finely warted, 7.4–8.6 µm diam. (Figure A14U,V).

Habitat: Recorded only in moist-chamber cultures, on dead wood of Quercus robur in Tilio-Carpinetum and on dead bark of Betula pendula.

Figure A14. Macbrideola rutilipedata (A–F): (A,B) Cylindrical sporocarps on female catkins of Alnus glutinosa; (C) Capillitium arising from the columella; (D) Capillitium with spores; (E) Spores; (F) Detail of distinctly spiny spores. Stemonitis axifera (G–L): (G) Tuft of rust-brown sporocarps on moss; (H) Single stalked sporocarp; (I) Columella with capillitium arising from its entire length; (J) Surface net with irregular meshes; (K) Spores; (L) Detail of spores showing a smooth surface. Stemonitis axifera var. smithii (M–Q): (M) Small tuft of pale ferruginous sporocarps; (N) Columella and internal capillitium; (O) Internal capillitium and surface-net elements; (P) Spores; (Q) Detail of nearly smooth spores. Stemonitis flavogenita (R–V): (R) Small tuft of brown to wood-brown sporocarps; (S) Columella nearly reaching the apex; (T) Capillitium with spores; (U) Spores; (V) Detail of densely and finely warted spores. Scale bars: (A,B,S) = 0.1 mm; (C,J,T) = 25 µm; (D–F,U) = 10 µm; (G) = 5 mm; (H,M) = 1 mm; (I,N,O) = 0.25 mm; (K,P) = 5 µm; (L,V) = 2.5 µm; (Q) = 1.25 µm; (R) = 2.5 mm.

Figure A14. Macbrideola rutilipedata (A–F): (A,B) Cylindrical sporocarps on female catkins of Alnus glutinosa; (C) Capillitium arising from the columella; (D) Capillitium with spores; (E) Spores; (F) Detail of distinctly spiny spores. Stemonitis axifera (G–L): (G) Tuft of rust-brown sporocarps on moss; (H) Single stalked sporocarp; (I) Columella with capillitium arising from its entire length; (J) Surface net with irregular meshes; (K) Spores; (L) Detail of spores showing a smooth surface. Stemonitis axifera var. smithii (M–Q): (M) Small tuft of pale ferruginous sporocarps; (N) Columella and internal capillitium; (O) Internal capillitium and surface-net elements; (P) Spores; (Q) Detail of nearly smooth spores. Stemonitis flavogenita (R–V): (R) Small tuft of brown to wood-brown sporocarps; (S) Columella nearly reaching the apex; (T) Capillitium with spores; (U) Spores; (V) Detail of densely and finely warted spores. Scale bars: (A,B,S) = 0.1 mm; (C,J,T) = 25 µm; (D–F,U) = 10 µm; (G) = 5 mm; (H,M) = 1 mm; (I,N,O) = 0.25 mm; (K,P) = 5 µm; (L,V) = 2.5 µm; (Q) = 1.25 µm; (R) = 2.5 mm.

Appendix A.14.4. Stemonitis fusca Roth, in Römer & Usteri, Magazin für Die Botanik 1(2): 26 (1787) [105]

Description: Sporocarps stalked, tufted or in groups, cylindrical, dark chocolate-brown to nearly black, 13–17 mm high; sporothecae rounded at base and apex, ca. 0.35–0.45 mm diam. and 9–11 mm high (Figure A15A). Hypothallus brown; stalks black, shining, 4–5.5 mm long. Columella continuous with the stalk, nearly reaching the apex. Capillitium arises from the whole columella, with angular, unequal meshes, a coarse inner net and fine surface net bearing spine-like projections (Figure A15B,C). Spores dark brown in mass, pale brown by transmitted light, reticulately spinulose, 8.3–9.6 µm diam. (Figure A15D,E).

Habitat: Recorded predominantly from moist-chamber cultures, with additional field collections on bryophytes and plant litter. The species occurred mainly on dead wood and dead bark, with occasional records from fallen leaves and woody twigs. Records were associated chiefly with Tilio-Carpinetum, Serratulo-Pinetum, Fraxino-Alnetum, and Querco-Piceetum communities and Natura 2000 habitats 9170, 91E0, and 91D0.

Figure A15. Stemonitis fusca (A–E): (A) Dark chocolate-brown to nearly black grouped sporocarps; (B) Capillitium arising from the whole columella; (C) Capillitium with angular, unequal meshes; (D) Spores; (E) Detail of reticulately spinulose spores. Stemonitis virginiensis (F–I): (F) Small group of red-brown sporocarps; (G) Capillitium arising along the columella; (H) Spores with capillitium; (I) Detail of verrucose-reticulate spores. Scale bars: (A) = 5 mm; (B) = 0.5 mm; (C,G) = 0.1 mm; (D,H) = 10 μm; (E,I) = 5 μm; (F) = 1 mm.

Figure A15. Stemonitis fusca (A–E): (A) Dark chocolate-brown to nearly black grouped sporocarps; (B) Capillitium arising from the whole columella; (C) Capillitium with angular, unequal meshes; (D) Spores; (E) Detail of reticulately spinulose spores. Stemonitis virginiensis (F–I): (F) Small group of red-brown sporocarps; (G) Capillitium arising along the columella; (H) Spores with capillitium; (I) Detail of verrucose-reticulate spores. Scale bars: (A) = 5 mm; (B) = 0.5 mm; (C,G) = 0.1 mm; (D,H) = 10 μm; (E,I) = 5 μm; (F) = 1 mm.

Appendix A.14.5. Stemonitis herbatica Peck, Bulletin of the Buffalo Society of Natural Sciences 1(6–9): 64 (1873) [106]

Description: Sporocarps shortly stalked, clustered, wood-brown, cylindrical, 3.5–4.5 mm high; sporothecae 0.2–0.5 mm diam. and 2.3–3.0 mm high, on stalks 1.0–1.2 mm long. Columella reaches the apex, commonly forming a conspicuous membranous discoid to funnel-shaped apical expansion. Capillitium arises from the entire columella, with coarse branches, expanded nodes, and a persistent delicate surface net of smooth threads with meshes. Spores dark brown in mass, brown in transmitted light, distinctly warted, 7.2–8.2 µm diam.

Habitat: Recorded only in moist-chamber culture, on dead leaves of Quercus robur in Tilio-Carpinetum and Natura 2000 habitat 9170.

Appendix A.14.6. Stemonitis virginiensis Rex, Proceedings of the Academy of Natural Sciences of Philadelphia 43(2): 391 (1891) [80]

Description: Sporocarps in small groups on a common hypothallus, stalked, cylindrical, red-brown, 4.5–5.2 mm tall, with sporothecae ca. 0.5 mm diam. (Figure A15F). Stalk black, 1.2–1.8 mm long; columella almost reaching the apex. Capillitium arising along the columella, with sinuously branched inner threads and a fine, partly fugacious surface net (Figure A15G). Spores light brown with purplish tint by transmitted light, 6.3–7.5 µm diam., conspicuously verrucose-reticulate (Figure A15H,I).

Habitat: Recorded in the field on dead wood in Tilio-Carpinetum and Natura 2000 habitat 9170.

Appendix A.15. Trichiaceae

Appendix A.15.1. Metatrichia floriformis (Schwein.) Nann.-Bremek., Proceedings van de Koninklijke Nederlandse Akademie van Wetenschappen, Series C, Biological and Medical Sciences 88(1): 127 (1985) [107]

Description: Sporocarps stalked, in large groups, sometimes several on a common stalk, 2–4 mm tall; sporothecae pyriform, dark red-brown, 0.5–1.2 mm high and 0.5–0.9 mm diam. Stalk deep red-brown, wrinkled, lacking spore-like contents. Peridium double-layered, rupturing in the upper part. Capillitium moderately elastic, red-brown; elaters 4.2–5.1 µm diam., smooth, with 4 spiral bands and long pointed tips. Spores brick-red in mass, bright yellow in transmitted light, finely warted, 10.2–12.7 µm diam.

Habitat: Recorded both in the field and in moist-chamber culture on dead wood, including wood of Quercus robur, in Tilio-Carpinetum forests and Natura 2000 habitat 9170.

Appendix A.15.2. Metatrichia vesparia (Batsch) Nann.-Bremek. ex G.W. Martin & Alexop., The Myxomycetes: 143 (1969) [32]

Description: Sporocarps stalked, clustered on a common stalk, rarely solitary, clavate or cylindrical, black or dark red-brown, shining, 1.4–2.4 mm tall (Figure A16A,B). Sporothecae 0.4–0.7 mm diam. Stalk dark red-brown, wrinkled, often flattened, usually 0.8–1.3 mm long. Peridium persistent, double-layered, dehiscing mainly by a sharply delimited dome-shaped apical lid. Capillitium rust-brown, very elastic; elaters 4.4–6.1 µm diam., spinose, with 3–5 spiral bands and short pointed ends (Figure A16C). Spores rust-brown in mass, bright yellow-brown in transmitted light, finely warted, 10.2–12.0 µm diam. (Figure A16D,E).

Habitat: Recorded mainly in moist-chamber cultures and once in the field, on dead wood of Betula pendula, Carpinus betulus, Alnus glutinosa, and Quercus robur. The species occurred mostly in Tilio-Carpinetum, with additional records from Fraxino-Alnetum and Querco roboris-Pinetum communities and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.15.3. Oligonema affine (de Bary) García-Cunch., J.C. Zamora & Lado, in García-Cunchillos, Zamora, Ryberg & Lado, Molecular Phylogenetics and Evolution 177 (no. 107609): 15 (2022) [108]

Description: Sporocarps sessile, densely crowded, broadly ovoid, yellow-brown, 0.6–1.1 mm diam., not higher than broad. Hypothallus brown, common to the group. Peridium yellow, shining, rupturing irregularly above and persisting basally as an incomplete cup. Capillitium inelastic; elaters yellow, 4–6 µm diam., with 3–4 closely wound spiral bands, longitudinally striate. Spores yellow in mass and by transmitted light, 12.5–14.7 µm diam., with incomplete reticulum.

Habitat: Recorded mainly in moist-chamber cultures on dead wood of Quercus robur, with an additional field record from herbaceous litter. The records included Tilio-Carpinetum and Natura 2000 habitats 9170 and 91E0.

Figure A16. Metatrichia vesparia (A–E): (A) Sporocarps clustered on a common stalk; (B) Mature sporocarps clustered on a common stalk; (C) Spinose elaters with spiral bands; (D) Spores; (E) Detail of finely warted spores. Oligonema flavidum (F–I): (F) Dull yellow, shining sporocarps crowded in heaps; (G) Lightly warted yellow elater; (H) Spores; (I) Spores with an almost complete coarse reticulum of narrow bands. Oligonema persimile (J–N): (J) Densely crowded, iridescent sporocarps; (K) Elaters with spores; (L) Elater with close spiral bands; (M) Spores; (N) Spores with incomplete reticulum and narrow marginal zone. Scale bars: (A) = 2.5 mm; (B,F,J) = 1 mm; (C,D,G–I,M) = 10 µm; (E,L,N) = 5 µm; (K) = 25 µm.

Figure A16. Metatrichia vesparia (A–E): (A) Sporocarps clustered on a common stalk; (B) Mature sporocarps clustered on a common stalk; (C) Spinose elaters with spiral bands; (D) Spores; (E) Detail of finely warted spores. Oligonema flavidum (F–I): (F) Dull yellow, shining sporocarps crowded in heaps; (G) Lightly warted yellow elater; (H) Spores; (I) Spores with an almost complete coarse reticulum of narrow bands. Oligonema persimile (J–N): (J) Densely crowded, iridescent sporocarps; (K) Elaters with spores; (L) Elater with close spiral bands; (M) Spores; (N) Spores with incomplete reticulum and narrow marginal zone. Scale bars: (A) = 2.5 mm; (B,F,J) = 1 mm; (C,D,G–I,M) = 10 µm; (E,L,N) = 5 µm; (K) = 25 µm.

Appendix A.15.4. Oligonema flavidum (Peck) Peck, Annual Report on the New York State Museum of Natural History 31: 42 (1878) [109]

Description: Sporocarps sessile, dull yellow, often shining, tightly crowded in heaps, globose, ca. 0.7–0.8 mm high and 0.45–0.5 mm wide, arranged in a dense single layer (Figure A16F). Peridium yellow, thin, granular and minutely warted. Capillitium scant, composed of yellow elaters 3.25–5.8 µm in diam., sparsely branched, lightly warted, partially smooth, locally narrowed or widened, with blunt apices (Figure A16G). Spores yellow in mass, 13.8–15.1 µm in diam., with an almost complete coarse reticulum of narrow bands (Figure A16H,I).

Habitat: Recorded in moist-chamber culture on dead wood of Alnus glutinosa in Fraxino-Alnetum and Natura 2000 habitats 91E0, 9170, and 91D0.

Appendix A.15.5. Oligonema persimile (P. Karst.) García-Cunch., J.C. Zamora & Lado, Molecular Phylogenetics and Evolution 177 (no. 107609): 15 (2022) [108]

Description: Sporocarps sessile, densely crowded, globose, light brown and often iridescent, 0.5–0.7 mm in diam. and ca. 0.7–1 mm high (Figure A16J). Hypothallus common, pale yellow; peridium pale yellow, rupturing irregularly above and persistent below, finely lined by transmitted light. Capillitium non-elastic, yellow, of elaters 4.5–6.3 µm in diam. with 3–4 close spiral bands, and fine yellowish or colourless spines (Figure A16K,L). Spores yellow to olivaceous brown, 12.0–14.5 µm in diam., with an incomplete reticulum and a narrow marginal zone (Figure A16M,N).

Habitat: Recorded in moist-chamber cultures on dead wood of Quercus robur in Tilio-Carpinetum forest and on dead wood of Picea abies in Serratulo-Pinetum and Natura 2000 habitat 9170.

Appendix A.15.6. Ophiotheca chrysosperma Curr., Quarterly Journal of Microscopical Science 2: 241 (1854) [110]

Description: Sporocarps sessile, globose or forming short sausage-shaped plasmodiocarps, dark black-brown, 0.5–0.7 mm in diam. (Figure A17A,B). Peridium double, outer layer dark-brown-granulate, often partly absent, inner layer translucent orange-yellow, dehiscing irregularly. Capillitium very elastic, pale golden yellow, of irregularly curved and branched threads 2.2–4.0 µm in diam., roughened and bearing spines to 7 µm long (Figure A17C,D). Spores pale yellow by transmitted light, 8–10 (12.1) µm in diam., densely and finely warted (Figure A17E).

Habitat: Recorded in moist-chamber cultures on dead bark of Carpinus betulus and on dead wood of Quercus robur from Tilio-Carpinetum forest and Natura 2000 habitat 9170.

Appendix A.15.7. Perichaena corticalis (Batsch) Rostaf., Pamiętnik Towarzystwa Nauk Ścisłych w Paryżu 6(1): 293 (1875) [111]

Description: Sporocarps sessile, densely crowded, flattened hemispherical, brown to dark brown, 0.5–0.8 mm in diam., rarely forming short plasmodiocarps; dehiscence circumscissile by a sharply delimited lid (Figure A17F,G). Peridium double, outer layer dark-brown-granulate, inner layer nearly colourless. Capillitium sparse, inelastic, golden yellow, little branched, with threads 3–5 µm in diam., minutely roughened (Figure A17H). Spores brown-yellow in transmitted light, 10.5–12.3 µm in diam., densely and finely warted (Figure A17I).

Habitat: Recorded mainly in moist-chamber cultures and occasionally in the field, on a broad range of substrates including dead bark, dead wood, fallen leaves, twigs, and leaf litter. Substrates included Betula pendula, Carpinus betulus, Alnus glutinosa, Quercus robur, Betula pubescens, Picea abies, and Pinus sylvestris, in Tilio-Carpinetum, Fraxino-Alnetum, Querco roboris-Pinetum, and Serratulo-Pinetum forests and Natura 2000 habitats 9170, 91E0, and 91D0.

Appendix A.15.8. Trichia botrytis (J.F. Gmel.) Pers. Complex, Neues Magazin für Die Botanik in Ihrem Ganzen Umfange 1: 89 (1794) [79]

Description: Sporocarps stalked, solitary, 2.1–3.0 mm high; sporothecae globose to pyriform, dark reddish brown, ca. 0.8 mm diam. with conspicuous yellow-brown reticulate dehiscence lines. Stalk dark brown, opaque, filled with irregular material, ca. 1 mm long. Peridium double, the outer layer divided into dark plates separated by paler membranous lines (Figure A17J). Capillitium honey-brown in mass, composed of inelastic elaters 3.5–5.2 µm diam., with 3–5 loose spiral bands and long, slender, sharply tapered tips (Figure A17K,L). Spores ochraceous brown in mass, yellow-ochraceous in transmitted light, finely warted, usually 9.6–12.2 µm diam. (Figure A17M). The material is treated as the Trichia botrytis complex because reliable separation of segregate species requires additional diagnostic characters beyond those available in the current study [65].

Habitat: Recorded exclusively from moist-chamber cultures, on fallen leaves of Betula pendula and dead wood of Quercus robur and Pinus sylvestris. The records were associated with forest habitats and Natura 2000 habitats 9170, 91D0, and 91E0, with one occurrence in Serratulo-Pinetum.

Appendix A.15.9. Trichia scabra Rostaf., Śluzowce (Mycetozoa), Monografia 6: 258 (1875) [66]

Description: Sporocarps sessile, densely crowded, short-cylindrical, 0.6–0.8 mm diam., 0.7–1 mm high, orange-brown to dark brown, often with a metallic-iridescent surface (Figure A17N). Peridium pale yellow, thin, smooth, shining. Capillitium honey-yellow to orange-yellow, non-elastic; elaters 4.5–5.3 µm diam., irregular, with 3–4 close spiral bands, finely spinulose and with short pointed free ends (Figure A17O). Spores orange in mass, bright amber-yellow in transmitted light, finely partly or completely reticulate, 9.9–11.5 µm diam. (Figure A17P).

Figure A17. Ophiotheca chrysosperma (A–E): (A) Sessile sporocarps with partly absent dark-brown outer peridium; (B) Short sausage-shaped plasmodiocarp; (C) Capillitium and spores; (D) Capillitial threads bearing spines; (E) Densely and finely warted spores. Perichaena corticalis (F–I): (F) Densely crowded sessile sporocarps; (G) Sporocarps with exposed spore mass; (H) Golden-yellow, minutely roughened capillitium; (I) Densely and finely warted spores. Trichia botrytis complex (J–M): (J) Sporocarp with outer peridial layer divided into dark plates separated by paler membranous lines; (K) Sharply tapered honey-brown elater tip; (L) Elater with visible spiral bands; (M) Finely warted spores. Trichia scabra (N–P): (N) Crowded sporocarps with metallic-iridescent surface; (O) Elaters with close spiral bands; (P) Spores with fine reticulate ornamentation. Scale bars: (A,B,F,G) = 0.5 mm; (C) = 25 µm; (D,K,L,O) = 5 µm; (E,H,I,M,P) = 10 µm; (J) = 2.5 mm; (N) = 1 mm.

Figure A17. Ophiotheca chrysosperma (A–E): (A) Sessile sporocarps with partly absent dark-brown outer peridium; (B) Short sausage-shaped plasmodiocarp; (C) Capillitium and spores; (D) Capillitial threads bearing spines; (E) Densely and finely warted spores. Perichaena corticalis (F–I): (F) Densely crowded sessile sporocarps; (G) Sporocarps with exposed spore mass; (H) Golden-yellow, minutely roughened capillitium; (I) Densely and finely warted spores. Trichia botrytis complex (J–M): (J) Sporocarp with outer peridial layer divided into dark plates separated by paler membranous lines; (K) Sharply tapered honey-brown elater tip; (L) Elater with visible spiral bands; (M) Finely warted spores. Trichia scabra (N–P): (N) Crowded sporocarps with metallic-iridescent surface; (O) Elaters with close spiral bands; (P) Spores with fine reticulate ornamentation. Scale bars: (A,B,F,G) = 0.5 mm; (C) = 25 µm; (D,K,L,O) = 5 µm; (E,H,I,M,P) = 10 µm; (J) = 2.5 mm; (N) = 1 mm.

Habitat: Recorded mainly from moist-chamber cultures on dead wood of Quercus robur and Betula pendula, and on dead bark of Carpinus betulus; it was also collected in the field from large dead woody debris. All records were from Tilio-Carpinetum and Natura 2000 habitats 9170 and 91D0.

Appendix A.15.10. Trichia varia (Pers. ex J.F. Gmel.) Pers., Neues Magazin für Die Botanik in Ihrem Ganzen Umfange 1: 89 (1794) [79]

Description: Sporocarps sessile, in small groups or densely grouped, yellow-brown to olive-brown, 0.5–0.8 mm diam. and up to 1.3 mm high. Hypothallus common, brown. Peridium pale brownish, thin, rupturing irregularly above. Capillitium olive-yellow; elaters 4.0–6.6 µm diam., with one or two loose spiral bands and short rounded to pointed ends. Spores yellow to olive-yellow, finely warted, 11.5–13.7 µm diam.

Habitat: Recorded exclusively by field collection, mainly on dead wood, with additional records from plant litter and dead bark. Occurrences were associated with Tilio-Carpinetum, Fraxino-Alnetum, and Querco roboris-Pinetum communities and Natura 2000 habitats 9170 and 91E0.