New Chorological Data for the Italian Vascular Flora

: Despite the importance for scientific and conservation purposes, the knowledge of the Italian territory is far from exhaustive. New chorological data for 87 vascular taxa regarding the central-southern part of Italy and its two main islands (Sicilia and Sardegna) are presented. Among these taxa, Epilobium nummularifolium , Metrosideros excelsa , and Salvinia minima are recorded as casual aliens for the first time in Europe (excluding Azores and Madeira for M . excelsa ), while Cyclamen balearicum and Polygala rupestris are reported for the first time and confirmed for Italian native flora, respectively. Furthermore, several taxa are new or confirmed at regional level. Finally, Lathyrus cirrhosus , Urginea fugax , and Linum tenuifolium are excluded from Italy, continental and peninsular Italy, and Sardegna, respectively. MC.F., E.B., E.L., VLA.L., CM.M., G.SP., G.ME., G.MI., G.SA., A.E., A.S.; writing—original draft preparation, L.R., A.S., CM.M., PJ.dL., and E.FAR.; review, all the authors.

However, despite the importance for scientific and conservation purposes, our knowledge of the Italian territory is far from exhaustive. In particular, in some regions of Italy, knowledge about the vascular flora remains inadequate usually because the geographic distributions of many species are poorly understood resulting in gaps in our knowledge of their actual extent [23]. This is the so-called "Wallacean shortfall," that is considered one of the crucial sources of uncertainty in biodiversity inventories, limiting both biosystematic and ecological analyses of these [24,25] and resulting in some exceptional discoveries when critical gaps are surveyed, such as finding of a new taxon of Gymnospermium (Berberidaceae) in an unexplored mountain range between Basilicata and Campania [26,27]. Further biological invasions represent a major threat to biodiversity [28,29], particularly as new naturalizations of alien vascular plants are continuously happening and are usually poorly documented within regional flora treatments. This is particularly the case on Mediterranean islands [30]. As a consequence, it is important that frequent assessment of regional floras are undertaken, not only to monitor the established populations (indigenous and naturalized), but also to update the distribution data to enable early warning of declines in indigenous or endemic species, and to document new arrivals of invasive plants, as an aid to better manage the invasive ones, particularly those species included in the European list of EU concern [31].
In this paper we document new observations of plants for the central-southern Italian Peninsula and the two main insular regions ( Figure 1). Our records include both native and alien non-cultivated species with a careful assessment of the status of naturalization for the latter. For each taxon, relevant information about ecology and distribution are also provided.

Materials and Methods
The floristic data are based on field investigation carried out by the authors in the study area, as well as on herbaria and literature surveys. The collected or examined materials are preserved in public (ANC, AK, HLUC, PORUN-Herb. Stinca, REGGIO, SS; acronyms according to Thiers [32]) or private herbaria. In the floristic list (Appendix A), taxa are arranged in alphabetical order. Nomenclature, taxa delimitation, and notes on the regional distribution follow the recent checklists of the Italian vascular flora [16,17] and their updates [33][34][35][36][37][38][39][40]. Nomenclature of the species that had not been previously reported from Italy and of Populus ×canescens follows World Flora Online [41]. The taxa recorded in this paper were identified using Flora Europaea [42][43][44][45][46], Flora d'Italia [18][19][20][21]47], and some monographic works cited in the species' note listed in Appendix A.
For each species the following information is provided: basionym and most relevant synonyms; plant family; life form, attributed on the basis of field observations using the categories of Flora d'Italia [47]; native range; period of introduction (archaeophyte or neophyte); data report in the study area; current invasiveness status for each region, assessed by population monitoring over time according to the terminology of Pyšek et al. [48]; date and discovery localities with details on the location (municipality, administrative province), habitat, altitude, decimal degrees geographic coordinates (datum WGS84); collector(s) (legit), author(s) of the identification (determinavit) and, eventually, the identity confirmation (confirmavit); herbarium where specimen is kept; additional notes. Species not documented with a herbarium specimen are shown in Figure 2.

Results
Two native and four alien species are recorded for the first time in Italy; among the aliens, three species deserve more attention since they are new for Europe. Overall, 87 taxa of floristic interest for the Italian flora are herein reported, 50 are native and 37 represent alien taxa. Among the native plants seven are endemic taxa of the Italian territory.

Native taxa
Cyclamen balearicum and Polygala rupestris discovered in Sardegna are recorded for the first time in Italy, while Euphorbia stricta found in Basilicata is recorded as new for peninsular Italy (i.e., the regions south to Toscana and Marche, Sicilia and Sardegna excluded). Lathyrus cirrhosus, previously reported by [49], is here excluded from the Sardinian and Italian flora.
In the same way, Linum tenuifolium reported from Sardegna [50] and Urginea fugax from Basilicata [51] are not confirmed throughout this study. These species seem to have been recorded by mistake and are here excluded from the floras of these regions.
Thirty-four taxa are new for the regional floras of the study area: 6 were found in Lazio (Dichoropetalum carvifolium-chabraei, Geranium pusillum, Hieracium pallescens s.l., Lathyrus inconspicuus, Oeosporangium tinaei, and Veronica spicata subsp. spicata), 6  In addition, two hybrids within the genus Rosa are reported in Basilicata for the first time (R. × bishopii and R. montana × R. villosa) and one (Populus ×canescens) in Sardegna. We also confirm 10 taxa as present in the regions covered by this paper: Prangos ferulacea in Lazio; Pedicularis petiolaris, Potamogeton pusillus, Puccinellia festuciformis subsp. festuciformis, and Viola kitaibeliana in Campania; Trifolium spumosum in Basilicata; Melampyrum barbatum subsp. carstiense and Nigella arvensis subsp. glaucescens in Puglia, Muscari parviflorum and Ophrys speculum in Calabria region. Finally, for one species (Impatiens noli-tangere), reported for the first time in Basilicata in the recent checklist of the Italian vascular flora [16] on the basis of our unpublished data, full details about the record are provided.

Alien taxa
Three alien species are recognized new for Europe (excluding Azores and Madeira for M. excelsa) and for Italy: Epilobium nummularifolium, Metrosideros excelsa, found in Sardegna, and Salvinia minima, found in Calabria. In the same regions, we found Coprosma repens, Pittosporum crassifolium (Sardegna) recorded for the first time in Italy, and Commelina erecta, recorded for the first time in Italy (Calabria) outside Sicilia. In addition to those species, 31 new alien vascular species are reported at regional level (two of these are present in two regions) :

Discussion
We reported 50 native taxa for the regions covered in this paper, including several endemic Italian taxa that are range extensions from their previous reported limits. The discovery in Sardegna of Cyclamen balearicum and Polygala rupestris, two species that had until now not been recorded for Italy, is particularly relevant because their presence provides additional support for the biogeographical link between Sardegna and the W-Mediterranean areas [52][53][54].
In the same way, the numerous neophytes reported for the first time in the regional floras once again confirm that alien species are continuously invading the environment. Although the majority of the recorded species have been evaluated with respect to their naturalization degrees as "casual," their monitoring over time is considered of primary importance in order to be able to effectively intervene if these species prove to be highly invasive. One especially noteworthy discovery is Salvinia minima, a species known to be invasive in most of the southern United States, where it is a significant threat to aquatic systems [55]. Salvinia minima is widely available for purchase for aquaria and watergardens in Europe. Accordingly, we think that this species established in Italy from the aquatic plant trade, probably as an accidental introduction. The high number of floristic records of international and regional relevance provided, after a very short time from the publication of the latest Italian vascular flora checklist [16,17], even if not derived from a systematic sampling activity, testify of the importance to continuously implement our knowledge of plant diversity, especially for conservation purposes, studying and reviewing herbaria collections, coupled with frequent field surveys with special attention to achieve an early warning to monitor introduction and naturalization of alien taxa.
Note: Casual or naturalized alien species in most of the peninsular and insular regions except for Umbria [17]. It is considered an invasive taxon in Toscana [17]. Note: A small population of this Italian endemic taxon, which grows in nature only in Puglia (Gargano peninsula) and doubtfully in Basilicata, was observed for over 10 years in anthropogenic habitat at Anticoli Corrado (Rosati, pers. observ.). These individuals have spread by seeds from a nearby cultivated plant in pots and urban gardens. Our specimens were identified using the key by [58]. Note: This alien species was reported as casual or naturalized only in Lombardia, Veneto, and Toscana [17]. Note: Collected from the margins of sidewalks where it was probably derived from a nearby flowerbed. This species has been recorded from Italian regions as casual or naturalized [17]; only in Sardegna is it considered invasive [17].

Chamaerops humilis L. Arecaceae
Nano-phanerophyte Neophyte, W-Mediterranean Note: Although this palm is indigenous to the neighboring regions of Campania and Calabria [16], it has not been recorded in the previous flora of Basilicata [51]. Therefore, as for the neighboring Puglia region [16], we consider it as introduced to this region. Plants probably spread from cultivation as the species was present in the nearby gardens, and only juvenile plants and seedlings were observed. Note: It is considered an archaeophyte associated with cereal crops, as stated for example in a previous record for Basilicata [59]. However, our finding of C. orientalis was in a silvo-pastoral habitat, quite far from cultivated areas. Note: Seedling collected from rank grassland within inner courtyard garden. Growing close to planted adult fruiting trees. Although this species is a very commonly cultivated tree in Sardegna, so far, only sparingly naturalizing. This may be because mostly only one clone is grown, and the species is self-incompatible [62]. Outside Sardegna this species has been reported as a casual alien only in Marche, Abruzzo, and Campania [17]. Note: At present known only from Calabria and Sicilia [16]. There are historical doubtful records of this species from Liguria and Campania, respectively [16]. Epilobium nummularifolium is apparently not known wild elsewhere in greater Europe [65]. However, this species has a superficial similarity to E. brunnescens (Cockayne) Raven et Engelhorn subsp. brunnescens, which is abundantly naturalized in the British Isles, and reported from the Guernesy Islands, so it is possible that it has been confused with that species, and so overlooked [65]. E. nummularifolium, a New Zealand endemic, is well-known for its aggressive, weedy nature. Raven and Raven [65] argue that this species was once a narrow range endemic of northern New Zealand, which has spread throughout that archipelago as a garden plant pot contaminant. We suspect that this is how it has reached Sardegna, i.e., as a possible soil/garden plant contaminant, introduced alongside anyone of the many New Zealand indigenous/endemic plants seen there in cultivation. This species should be looked for elsewhere in Europe. Epilobium nummularifolium is distinguished from both E. brunnescens and E. komarovianum H. Lev, which is also naturalized in Europe [65] by the yellow-green, serrulate leaves, purple-blue stems, and grey-strigulose capsules [65][66][67][68] (Table A1, Figure A1). These species are keyed out as follows:   Note: Euphorbia nutans was recorded as casual or naturalized alien in most of the Italian regions [17]. It is considered invasive in Lombardia and Veneto [17]. Note: Previously, and reliably reported only from the northern Italian regions [16]; this record provides the first verified evidence of its presence in peninsular Italy. Previously it was considered as doubtfully present in Lazio [16], while it has not been recently recorded from Abruzzo and Calabria [16], and was apparently recorded by mistake from Sicilia [16]. Note: This species is known with certainty only from the northern Italian regions [17]; otherwise considered doubtfully present in Lazio, and not recently confirmed from Abruzzo and Calabria (after 1950) [17]. In Basilicata it was observed escaping from small cultivated fields of buckwheat. In the Calabria region it was observed for some years as a weed of vegetable gardens and along arable land edges. Note: Treated as a casual alien in Sardegna, Campania, and Puglia; naturalized in Sicilia [17]. Recently recorded in southern Italy for Calabria [14].  [17]. Plant samples were identified using the diagnostic characters and keys of [69][70][71]. Note: This species is present in all the northern regions of Italy except for Liguria [16]. In peninsular Italy it was recorded only from Abruzzo, Campania, Basilicata, and Calabria [16]. About twenty subspecies of H. pallescens are present in Italy; however, our specimen does not allow to ascertained the subspecific level. Further on filed investigations should be performed to fix this gap. Note: This species is present in Italy in the north-western (Piemonte, Liguria, Toscana and Emilia-Romagna) and in the southern regions with a clear gap in central Italy [16]. Although it is a very showy orchid it was never seen before in Sardegna, probably because of its rarity.  [16].

Ranunculaceae
Geophyte rhizomatous Eurasian  [16]. Our finding is the first for Mediterranean islands. This is noteworthy as it is believed to be absent from Corsica [72]. Note: At Maratea Kalanchoë ×houghtonii seems to form populations capable of self-sustaining reproduction. Indeed, because of the viviparous nature, whereby the leaf lamina produces myriad plantlets this species has the potential to be highly invasive. It is recorded as naturalized from Liguria, Toscana, Lazio, and Calabria; it is present as casual in Campania, Puglia, Sardegna, and Sicilia [17]. Note: Previously reported as a casual alien only from Liguria and Calabria regions [17]. In Sardegna this species is widely grown in urban green areas, pots, and Mediterranean gardens (pers. observ.) so further naturalizations are likely.

Lathyrus cirrhosus Ser. Fabaceae
Hemicryptophyte NW-Steno-Mediterranean Exclusion for Italy (Sardegna) Note: This taxon was reported only once at Monte Arviganu and Monte S. Giuliano, near Alghero, Sardegna by Schmid [49]. Pignatti [19,47] and Arrigoni [73] stated that the presence of L. cirrhosus in Sardegna is doubtful because of the probable confusion with L. heterophyllus L. Nevertheless, it was considered present in Sardegna in the Italian Flora checklists of vascular plants [16,74]. We have unsuccessfully searched for this species in the two sites during the last decade, and in the absence of verified herbarium evidence of its historic presence we recommend that L. cirrhosus be excluded from the flora of Sardegna and Italy.

Lathyrus inconspicuus L. Fabaceae
Therophyte scapose Euri-Mediterranean Note: In peninsular Italy L. incospicuus was previously recorded from Toscana, Marche, Abruzzo, and Puglia; indeed, in Umbria and Campania its presence is doubtful [16]. It is absent in the southern and insular regions [16].

Linum tenuifolium L. Linaceae
Chamaephyte subshrubs Steno-Mediterranean-Euxinian Exclusion for Sardegna Note: The presence of this taxon in Sardegna was reported by Mossa et al. [50] and so accepted in the Italian checklist of vascular flora [16,74]. Nevertheless, the species is excluded by [75] who considers its presence a mistake, because of the confusion with L. bienne. Our surveys in the site from where Linum tenuifolium was reported by Mossa et al. [50] found only L. bienne. Therefore, L. tenuifolium has to be excluded from Sardegna. It was also reported by mistake in Sicilia region [16].

Caprifoliaceae
Phanerophyte climbing Neophyte, E-Asia Note: Lonicera japonica has been recorded from all Italian regions except for Molise and Basilicata [17]. It is considered invasive in several regions of Northern Italy [17]. Note: Previously reported from the Italian Peninsula for all of the regions, except Abruzzo, Molise, and Campania [16]. Note: A few seedlings, and saplings growing in the vicinity of the planted adult trees; this species is common in many coastal towns and resorts around Sardegna (see for example https://inaturalist.nz/observations/1715168). Metrosideros excelsa, commonly known as "New Zealand Christmas tree," is a coastal evergreen tree that produces a brilliant display of red flowers. It has been recently added to the list of host plants referred to in Article 1(b) of Commission Implementing Decision (EU) 2015 2417 of 17 December 2015, which have been found to be susceptible to Xylella fastidiosa in the European Union territory. Until this record Metrosideros excelsa had been recorded in Europe as a naturalized plant only from the Azores and Madeira (Portugal) by [76]. Thus, our finding represents the first record for Europe (Azores and Madeira excluded).

Asparagaceae
Geophyte bulbouse Central-E-Mediterranean Confirmation for Calabria Specimen: 10-10-2011, Orsomarso (Cosenza), fallows, 488 m a.s.l., 39.78545° N-15.90759° E, leg. et det S. Fascetti (HLUC). Note: Previous records of this species from Calabria had been considered doubtful [16]. Note: This species was recorded in Italy from several regions; it is present in almost all of the central and northern regions as a casual alien; in Piemonte, Trentino-Alto Adige, and Friuli-Venezia Giulia it is considered naturalized [17]. It is absent in most of the southern regions, except for Sicilia [17].  [16]. However, O. miliaceum is the only species that has ever been considered present in the flora treatments of Sardegna e.g., [47,74,75]. In addition, several authors consider questionable the distinction between these two taxa and include O. thomasii in O. milaceum. Our observations confirm the presence of O. miliaceum, accordingly this name has to be re-added to the checklist of vascular flora of Sardegna. O. miliaceum is present in almost all Italian regions except Valle d'Aosta, Piemonte e Molise [16].  Figure 2). Note: This species was previously recorded in almost all the peninsular regions except for Puglia, Calabria, and Basilicata. This observation extends southward the range of this endemic taxon in Italy [16]. It is absent in the insular regions [16]. Note: At these locations only a few plants were recorded growing in the crevices and at the edge of the roadside; these probably escaped from plants cultivated in pots on the sidewalks. It is reported for several regions of Italy as a naturalized or casual alien [17]; it is considered doubtfully present in Lazio, Basilicata, and Puglia [17].

Oxalis latifolia Kunth
Oxalidaceae Geophyte bulbouse Neophyte, America Note: In Italy it was previously reported only for Abruzzo, Basilicata, and Calabria regions [16]. In Campania it had previously only been considered doubtful present [16].

Pittosporum crassifolium Banks and Sol. ex A. Cunn. Pittosporaceae
Nano-phanerophyte Neophyte, New Zealand First record for Italy (casual) Specimen: 11-03-2013, Sardegna, Lungomare Valencia (Alghero, Sassari province), at back of disco bar near former castle, 9 m a.s.l., 40.55058° N-8.31974° E, leg. et det. P.J. de Lange (AK) Note: Associated with the superficially similar Pittosporum tobira (by far the most commonly grown and naturalized Pittosporum species in Sardegna). Pittosporum crassifolium was only seen here and at Torre Nuova (Alghero). Seedlings occasional, these appear to be pure Pittosporum crassifolium. In Europe it has previously recorded only from Great Britain [60]. Note: In southern Italy it was previously recorded only for Campania (naturalized) and Sicilia (casual) [17]. Note. In Calabria, we observed a few individuals growing along the roadside; these had probably escaped from a nearby garden. It is reported as casual alien from almost all the regions of Italian peninsula, except for Umbria, Molise, and Basilicata; in Sardegna it is considered naturalized [17]. Note: In the recent checklist of the Italian vascular flora the presence of this species was considered doubtful in Italy [16]. We found this species in Sardegna along the coast South of Alghero, where it was usually present, though at low densities in the calcareous coastal garrigues. The nearest known localities of this species, according to Flora Gallica and Flora Iberica are in Provence (S-France) and Balearic Islands (Spain). Note: In North Sardegna this species was also reported in a vegetation survey from the Cala Regina (Isola dell'Asinara, Sassari province) by [78]. In Italy it is widespread and known from all regions except for Liguria. This hybrid was reported for Sardegna by Camarda and Valsecchi [79] and Arrigoni [80] but not subsequently considered (by mistake?) in the recent checklist of vascular flora [74,16]. In the last checklist of the Italian vascular flora [16] it is not indicated as a hybrid (i.e. P. canescens (Aiton) Sm). Note: Outside Campania this species is not known from the southern Italian Peninsula [16]; it was recently confirmed from Basilicata [39]. Note: Doubtfully reported from Lazio on the basis of a historic record (1914) from Terminillo of Cavara and Grande which had not been confirmed by recent surveys [81]. On the basis of the record above Prangos ferulacea is now verified from the Lazio region. This species is, with the exception of Molise, otherwise known from the other regions of the Italian Peninsula [16].  [83]. According to some authors, it is probably the most common hybridogenic species among the dog roses [84]. To the best of our knowledge, a binomial name for this hybrid does not exist yet. As a consequence, chorology for this taxon is not defined. Note: Salvinia minima is a non-rooted aquatic fern native to South and Central America. Madeira et al. [85] report this species as locally introduced for Spain, citing Lawarlee in Flora Europaea [42]. However, S. minima is not considered in Flora Europaea, neither in Flora Iberica [86]. For this reason, it may be that this record for Calabria is not the first for Italy but also for Europe. In this context, a case of accidentally introduction of Salvinia minima in Europe has been only documented in the botanical garden greenhouses in Jibou, Romania [87]. Detailed images of plants collected in Calabria are shown in Figure A2. The collected plants were identified using [88][89][90][91]; diacritical characters useful to distinguish S. minima with respect to the most similar taxa are shown in Table A2.   Note: Present in central and northern regions of Italy but in southern regions, records of it from Puglia, Basilicata, and Calabria have been treated as mistakes [16]. Therefore, the discovery of Mt. Volturino reported here now confirms its presence in the southern Apennine. Note: This species has been recorded as casual alien from many Italian regions [17].  [17]. Prior to this record this species was known from Sardegna on the basis of old reports that required confirmation [17]. Note: The presence of this species in Italy was ascertained only from Sardegna, Sicilia, Calabria, and Lazio [16]. In recent times this species has not been recorded from most of the Italian peninsular regions [16]. Our discovery from Basilicata confirms its continued presence from at least part of that region.

Urginea fugax (Moris) Steinh. [≡ Anthericum fugax Moris] Asparagaceae Geophyte bulbouse W-Mediterranean
Exclusion for continental and peninsular Italy (Basilicata) Note: In Italy, we can only confirm this species as present in Sardegna [16], which is consistent with its W-Mediterranean distribution. Accordingly, we regard past records of the species from Basilicata and neighboring regions as erroneous. Although Gavioli [51] reported the species from Basilicata in 1915 the samples he noted had been lost, so the record cannot be verified. In absence of further specimens of this distinctive plant from the Italian Peninsula we suggest that U. fugax had probably been reported by mistake, because of the confusion with a similar species (likely small size individuals of Urginea maritima auct. Fl. Ital.). Therefore, we recommend that this species is excluded from the flora of Basilicata. Note: In Italy this taxon has a northern (Lombardia, Trentino-Alto Adige, Veneto) and central (Marche, Umbria, Abruzzo) disjunct distribution [16]. In Piemonte it is recorded by mistake [16]. Subspecies identification of our samples was based on the key reported in [20]; however, in our view the subspecies delimitation of V. spicata as stated in [20] is unclear and needs further study. Note: Viola kitaibeliana is recorded from most of the peninsular regions, except for Emilia-Romagna, Molise, and Puglia; it was previously considered as doubtfully present in Campania [16]. Our discovery now fills this gap along the Apennine chain. Note: A few individuals of Wisteria sinensis were noted growing together with Phyllostachys aurea and Plumbago auriculata along the roadside, probably escaped from a nearby garden. Previously Wisteria sinensis was recorded as casual alien from almost all of the Italian regions but only from Campania in the southern ones [17]. In Sardegna it is considered naturalized [17].