Bulbophyllum abangjoei sp. Nov. (Orchidaceae: Dendrobieae), A New Species of Orchid from Sarawak

: Bulbophyllum abangjoei is a new one ‐ flowered orchid species described from Lanjak Enti ‐ mau Wildlife Sanctuary, Katibas and Anap ‐ Muput, Tatau, Sarawak. The taxonomic treatment is ac ‐ companied by taxonomic notes, information on the species’ affinities at infrageneric level, geograph ‐ ical distribution, habitat ecology, and implications for their conservation. It is morphologically al ‐ most similar to Bulbophyllum deviantiae , B. membranifolium , and B. sanguineolentum , but clearly differs in the long, narrowly oblong to linear leaf blade, subsessile petiole ca. 5 mm long, long narrowly cylindrical pseudobulbs with some mature pseudobulbs reaching ¾ length of the leaf blade, non ‐ resupinate flowers, shortly upcurved and not emarginate labellum apex, and elliptic ‐ oblong stelids at lower margins near the apex of the column. For these morphological differences, B. abangjoei is here described as distinct and new species to science. The new species is so far only known from three localities in protected areas in Sarawak, and hereby is assessed as ‘Endangered’ [EN B2 (a)(b) D1] under IUCN Red List criteria B and D.


Introduction
Bulbophyllum Thours is probably the largest genus within Orchidaceae with more than 2000 species [1,2,3,4]. Borneo is probably one of the richest areas with about 300 species of Bulbophyllum and over 150 endemic species [4]. Vermeulen and O'Byrne reported 30 new species of Bulbophyllum found in Borneo Island [5]. In general, Bulbophyllum has sympodial rhizome either creeping or hanging loosely with distinct or inconspicuous pseudobulbs; new shoots and inflorescence are usually arisen from one of the nodes below the pseudobulb (never from the apex of pseudobulb), inflorescence maybe culminates one to many flowers, and the labellum is mobile as it is hinged to the column foot [1,2]. Most Bulbophyllum species are epiphytic, delicate, and drought-resistant. Bulbophyllums employ a 'drought escape' adaptive strategy by being deciduous, and shedding leaves and roots during dry conditions can minimise energy loss through transpiration [6,7]. Some species, such as B. bakhuizenii, B. obtusum, and B. pileatum, can survive and produce flowers or seed pods under harsh environments, including logged forest areas with opened canopies and extreme microclimate conditions [7]. Secondary forest and rubber plantations may harbour Bulbophyllum species, such as B. vaginatum, B. macranthum, and B. patens. Nevertheless, undisturbed or pristine habitats with high moisture and intermediate light exposure are particularly favoured such as on trees along the riparian forest area. About 14 years ago, in 2008, in the course of inventorying wild orchid diversity within the Lanjak Entimau Wildlife Sanctuary (LEWS), during a scientific expedition jointly organised by Academy of Science Malaysia (ASM) and the Forest Department of Sarawak, a new species of single-flowered Bulbophyllum was discovered and is described here after a few more the same specimens were collected from other locations.

Materials and Methods
Samples with floral structures were preserved using standard herbarium technique after Bridson and Forman [8] and voucher specimens were deposited in the Herbarium of Universiti Putra Malaysia (UPM) at the Department of Biology, Faculty of Science, UPM, Selangor, Malaysia, and Herbarium of Sarawak (SAR) at Research, Development, and Innovation Division (RDID), Forest Department Sarawak (FDS), Kuching, Sarawak, Malaysia. The robust non-flowering individuals were brought to the Anap-Muput Forest Management Unit (FMU) and transplanted into the ex situ conservatory as living collections. Herbarium specimens, orchid taxonomic monographs, and protologues on Bulbophyllum were referred to and studied for species identification. Plant materials which deposited K, SAB, SAR, and SING were examined through visits to the herbaria. Digitalised images of herbarium collections (AMES, AUU, BM, BO, K, MNHN, NHN-L, SING), botanical drawings, and records deposited in the Global Biodiversity Information Facility (GBIF) (https://www.gbif.org/), the National Herbarium of the Netherlands (NHN) accessed through Browse Dutch Natural History Collections: BioPortal (Naturalis) (http://bioportal.naturalis.nl/), Herbarium of Singapore Botanic Gardens (SING) accessed through BRAHMS Online managed by the University of Oxford (http://herbaria.plants.ox.ac.uk/bol/sing), the Swiss Orchid Foundation (https://orchid.unibas.ch/index.php/en/), the Kew Herbarium Catalogue (http://apps.kew.org/herbcat/gotoSearch-Page.do), the Natural History Museum Specimen Collection (https://data.nhm.ac.uk/), the Herbarium of Aarhus University (AAU) (https://www.aubot.dk/search_form.php), Museum National D'Histoire Naturelle (MNHN) (https://science.mnhn.fr/all/search), and Plants of the World Online (POWO) (http://www.plantsoftheworldonline.org/) were examined prior to the taxonomic delimitation of the species complex, providing insights into morphological distinctness of the new species. Accepted names of the closely related taxa were validated via KEW World Checklist of Selected Plant Families (WCSP) [9] and Plants of the World Online (POWO) (https://powo.science.kew.org/).

The Discovery
The first sight and collection of this species was during a scientific expedition to Ulu Ketibas, Lanjak Entimau Wildlife Sanctuary in 2008 [10]; subsequently, another population was discovered in Mulu National Park in 2016. In 2021, during an orchid rescue operation in Anap-Muput FMU active felling compartment (Figure 1), we discovered a few of the same plants among the rescued plants. When the plant flowered in February 2022, coupled with our detailed consultation and study of all online (K, NHN-L, AMES, BM, BO, AUU, MNHN) and physical (SING, SAR, UPM, SAB) herbarium resources for all major Bornean orchid flora, we were finally confident to describe it as a new species. The process to validate this beautiful gem took us almost 14 years and involved extreme and harsh fieldwork environments and numerous herbarium study visits. This included hundreds of hours of laborious strenuous fieldwork tracking and herbarium specimens' study. However, the long strenuous journey of this discovery is nothing when compared to the honour and joy of discovering new species to science and endemic to Sarawak, as this species is only found in Sarawak; hence, it is categorised as 'Endangered' according of IUCN Red List criteria and categories.  Morphological description: --Plants epiphytic herbs. Roots mainly below the pseudobulbs. Rhizome creeping, 2-3 mm diameter, brownish; bract persistent, membranous, greenish brown, old bracts brown and fibrous. Pseudobulbs 5-10 mm apart, narrowly oblong to cylindrical, terete, long, mature ones ¾ length of the leaf blade, sometimes almost the same length as the leaf blade, 4-10 × 0.3-0.5 cm, with shallow and inconspicuous furrows, basal covered by brown sheaths. Leaves sub-sessile, rather thin, narrowly oblong to narrowly linear blades, apex acute, 18-20 × 1-1.5 cm, medium green; petiole ca. 5 mm long, terete and groove above. Inflorescence about 3 cm, one-flowered, emerging from rhizome at the base of the pseudobulb, sometimes two inflorescences emerging from a single node that may resemble a raceme, basal part with subtending bracts; peduncle 12 mm long; pedicel-with-ovary 10-12 mm long, basal node of pedicel approximate level with the floral bract attachment, ovary 3.6 × 1.7 mm, with angular crests; floral bracts ovate, ca. 6 × 4 mm, apex acute. Flowers non-resupinate, unscented, ca. 5.5 cm long from tip of dorsal sepal to tip of lateral sepals when open, wide opening, ca 2.5 cm wide, sepals and petals glabrous, 6-8-veined; pedicel-with-ovary about 10 mm long, ovary ribs with angular crests. Dorsal sepal rather thin, ovate, 1.5 × 0.7 cm, apex acute, slightly upcurved at tip, margins entire to erose, glabrous, 7-8-veined. Lateral sepals free, 2.2 cm long, 0.6 cm wide at base, oblong-lanceolate, slightly falcate, longer than the median but firmly adherent along the lower margins, concave, margins entire to erose, 7-8-veined. Petals rather thin, with five pink linings, ovate, 13 × 5 mm, apex acuminate, oblique, glabrous, margins entire to erose, 5-7-veined. Labellum resembles Alladin's shoes, recurved towards base and towards tip, thick, ovate, 5-7 × 2-3 mm, adaxially with a median furrow running from the base to apex, margin erose; apex obtuse, swollen, shortly upcurved ca. 1 mm forming a short transverse furrow at the abaxial side, margin erose, adaxial surface verrucose at the proximal margins bordering the median furrow; base hinged on a thin ligament to the column foot, with conspicuous, antrorse, rounded auricles at base, at about 1/3 along the length of the labellum. Column including stelidia ca. 7-10 mm long; stelidia rounded with an apiculate apex, ca. 0.7 mm long, lower margin with a distinct, porrect, large, ellipticoblong, obtuse ca. 1.6 mm long tooth; anther-cap ca. 1.6 × 1.3 mm, cucullate, oblong-ovate, verrucate at lower margins; pollinia two (only two of four pollinia were seen in the spiritpreserved specimen), 0.7 × 0.7 mm, oval. Seedpods green, spatulate with large, acutely angular ribs. Colours: --Sepals and petals white to pale yellow with 5-8 pink-purple stripes from base to apex along the veins; labellum dark red or purple, pinkish purple with abaxial part whitish, finely spotted purple; column whitish flushed dark purple, anther cap dark purple.

Taxonomic Treatment
Phenology: --Flowering in January-March and June. Habitat and ecology: --Epiphyte on tree branches and trunks ( Figure 3). Found growing in riverine and inland habitats with less exposed or partially shaded spots. Often rooting in mossy branches and trunks. The current known localities (riverine) are all flood prone vegetation and major river transportation routes, indicating the high possibility of anthropogenic and natural catastrophe to this species population.
Etymology: --The species epithet, abangjoei, is after "Abang Joe" or Abang Zohari Abang Haji Openg, the current Honourable Premier of Sarawak. Bulbophyllum abangjoei Go, Besi and Pungga sp. nov. is truly synonymous to The Honourable Premier of Sarawak, Abang Joe in charisma. The flowers (sepals and petals) are white to cream colour with striking pinkish-purple stripes that signify his boldness and outstanding determination to safeguard the state biodiversity grandeur, boosting the exploration, conservation, and restoration of major landscapes in support of UN Decade on Ecosystem Restoration, that was aimed at preventing, halting, and reversing the degradation of ecosystems on every continent. The nature of the plant habit that is resilient against drought and occasional flood denotes Abang Joe's resilience towards peer pressure, political upsurge, and global environmental mandate.

Discussion
Taxonomic notes: --Bulbophyllum abangjoei sp. nov. is part of a small group of oneflowered Bulbophyllum species belonging to Bulbophyllum sect. Sestochilus (Breda) Benth. and Hook.f. (1883) and Bulbophyllum sect. Beccariana Pfitz. (1889), Group C and Group D fide [4], artificial key to the Asian sections of Bulbophyllum [12], that have a rather large solitary flower relative to the elliptic to linear leaf blades and ovoid to cylindrical pseudobulbs, such as Bulbophyllum cornutum (Blume) Rchb.f. in W.G.Walpers, Bulbophyllum elevatopunctatum J.J.Sm., Bulbophyllum deviantiae J.J.Verm. and P.O'Byrne, Bulbophyllum ecornutum (J.J.Sm.) J.J.Sm., subsp. ecornutum, Bulbophyllum ecornutum subsp. verrucatum J.J.Verm., Bulbophyllum incisilabrum J.J.Verm., Bulbophyllum membranifolium Hook.f. subsp. membranifolium, Bulbophyllum membranifolium subsp. inunctum (J.J.Sm.) J.J.Verm., Bulbophyllum rugosum Ridl., and Bulbophyllum sanguineomaculatum Ridl., which all were previously in sect. Beccariana. This new species is here categorised belonging to sect. Beccariana, Group D with one-flowered inflorescences, basal node of pedicel approximate level with floral bract attachment, margins of median sepal entire, floral bract not tubular but instead amplexicaul (basal part surrounding the stalk from which it arises) with the basal edges just connected at the base, sepals with 5-19 veins (7-8 veins on B. abangjoei), and median sepal free instead of connate to the lateral ones. Within sect. Beccariana, B. abangjoei is most closely related to B. deviantiae, B. elevatopunctatum, B. membranifolium subsp. membranifolium, B. membranifolium subsp. inunctum, B. rugosum, and B. sanguineomaculatum, which are almost similar in the flower's patterns and colour variations. However, the new species is easily distinguished and distinct. The most significant diagnostic morphological characters of B. abangjoei are the long narrowly oblong-linear leaf blades ca. 1 cm width (instead of obovate or elliptic), long terete pseudobulbs in which mature plants have psedudobulbs almost as long as the leaves, non-resupinate flowers, and elliptic-oblong stelids at lower margins. Interestingly, amongst the 67 provisionally accepted species in B. sect Beccariana (fide [4]), B. abangjoei is so far the only member of the infrageneric section with long narrow leaf blades (up to 10 cm long) and pseudobulbs. In addition, most of the species in the one-flowered sect. Beccariana exhibit resupinate flower. Apart from the long oblong-linear leaf blades with sessile petiole and long terete pseudobulbs, it clearly differs from B. deviantiae, B. membranifolium, B. rugosum, and B. sanguineomaculatum; a group which shares an almost similar flower colour variation by having apiculate stelids and shortly upcurved and swollen labellum apex (Table 1). It differs from B. elevatopunctatum by having flowers not scented, not spotted, with prominent pink-purple stripes from base to apex along the veins of the tepals, lateral sepals strongly adherent at lower margins instead of loosely adherent and reflexed at apices, as in most of the closely related species (Table 1).
Artificial key to one-flowered Bulbophyllum sect.  [4], and a description for B. deviantiae was retrieved from [13].
Species references:--Bulbophyllum deviantiae J.J.Verm. and P.O'Byrne, Gard. Bull. Sin-their care. Special thanks also go to Nora Abdul Karim, Serena Lee, and Madam Davi at the SING for their kind assistance with the digitised images of Bulbophyllum.