Bulbophyllum jingdongense A. Q. Hu, D. P. Ye & Jian W. Li, 2017

Bulbophyllum jingdongense A. Q. Hu, D. P. Ye & Jian W. Li View in CoL , sp. nov. ( Figs. 1–2 View FIGURE 1 View FIGURE 2 )

Types:— CHINA. Jingdong County, Pu’er, Yunnan Province. Epiphytic on trees in mixed broad-leaved and coniferous forest, 1550 m elevation, 17 Jan 2016, A.Q.Hu et al. 803 (holotype: NOCC!) ; Jingdong County, Pu’er, Yunnan Province. Epiphytic on broad-leaved tree, in broad-leaved and mixed forest, 1600 m elevation, 11 Mar 2013, Jian-Wu Li 2959 (paratype: HITBC!) ; Jingdong County, Pu’er, Yunnan Province. Epiphytic on tree, in mixed broadleaved-coniferous forest, 1570 m elevation, 17 Feb 2016, Jian-Wu Li 4494 (paratype: HITBC!) .— LAOS. Khammouane Province, Nakai District, near Nam Theun Reservoir , twig epiphyte on remaining tall, mature Pinus trees in logged mixed Dipterocarp–pine forest, 547 m elevation, 25 Oct 2014, S. Gale et al., HNL-KFBG 0409 (paratype) , living collection in cultivation at Biotechnology and Ecology Institute [BEI], Ministry of Science and Technology [MOST] , Vientiane, Laos PDR .

Diagnosis: Bulbophyllum jingdongense differs morphologically from all previously described species in the Cirrhopetalum alliance by the following combination of characters:subglobose or compressed subglobose pseudobulbs; sepals and petals with dense, reddish-purple papillae abaxially; lateral sepals connate at the base and free at both ends, further connivent along the upper edges and strongly incurved to form 2 horns, obtuse on each apex; a column with a prominent, broad, ellipsoid, orange-yellow gland below the stigma; and a stelidium basally truncate, acuminate, merging with the column wings on each side of the column.

Epiphytic herbs. Rhizome creeping, ca. 1 mm in diam., rooting from base of pseudobulbs. Pseudobulbs spaced at 2–10 mm intervals along the rhizome, finely wrinkled, compressed sub-globose, 6–7 mm tall, 8–10 mm in diameter, dark green or reddish-purple, apex 1-leaved. Leaf not deciduous; laminas elliptic, 10–14 × 8–12 mm, leathery, 1- veined, adaxially concave and dark green, abaxially convex and reddish-purple, base rounded, sharply contracted into a apex obtuse-rounded and emarginate, borne on very short petiole-like stalk up to ca. 1 mm long. Inflorescence arising from base of terminal pseudobulb, sub-umbellate, 4–6-flowered; peduncle 9–11 mm long, 0.8–1 mm in diam., with 2 tubular, membranous sheaths; sheaths 6–8 × 3–4 mm, apex acute; floral rachis short, ca. 2–2.5 mm long; floral bracts lanceolate, 4–5 × 1–1.2 mm, apex acuminate. Flowers slightly sweetly scented; pedicel and ovary 1–1.2 mm long, with reddish-purple papillae; sepals and petals pale yellow with dense reddish-purple papillae on abaxial surfaces; lip dark purplish-red adaxially and pale pinkish-red abaxially. Dorsal sepal ovate-triangular, 4.5–5.5 × 3.5–4 mm, 3- veined, margin entire, apex acute; lateral sepals lanceolate, 8–9 × 2–2.5 mm, 3-veined, basally adnate to column foot, basal half of lower edges connate, upper edges strongly incurved and connivent at the middle, apically separate, both lower and upper edges strongly incurved, apices horn-shaped, obtuse; petals oblong, 2.5–3 × 1–1.2 mm, apex acute; lip ligulate, attached to apex of column foot by mobile joint, fleshy, 2.7–3 × 1.2–1.5 mm, apex rounded, centrally concave. Column pale yellow, flushed pink at apex, subcylindrical, ca. 2 mm long; with a single, prominent gland beneath the stigma; gland bright orange-yellow, ellipsoid, ca. 0.2 mm in diam.; rostellum present, above concave stigma; column foot incurved, 2.6–3 mm long, with free part 1.6–2 mm long; stelidia, well-developed, 2.5–3 mm long, basally truncate, apex acuminate and slightly erose, merging with the column wings at apex; anther cap yellow, helmet-shaped, glabrous, entire.

Phenology: —Flowering specimens collected in Yunnan, China from January to March; fruits not seen. The Lao plant at BEI has not yet flowered since being brought into cultivation.

Distribution and habitat: — Bulbophyllum jingdongense is currently only recorded from Yunnan Province in Southwest China and Khammouane Province in central Laos. In China, it inhabits mixed broadleaved and coniferous forests, where it grows epiphytically on the rough bark of several tree and shrub species ( Fig. 2. A & B View FIGURE 2 ), including Castanopsis (D.Don) Spach spp. , Lyonia ovalifolia (Wall.) Drude and Vaccinium bracteatum Thunb. In Laos, it grows in the crown of Pinus merkusii Jungh. & de Vriese trees in mixed Dipterocarp-pine forest. It appears to prefer a shaded and cool environment at elevations over 500 m, with plants usually rooted in shallow leaf detritus on slender branches and twigs in the canopy.

Conservation status: —We found more than ten clusters of Bulbophyllum jingdongense , each comprising 20–50 pseudobulbs, growing epiphytically on different shrubs and trees at the holotype locality in the Wuliang Mountain Nature Reserve in Jindong County. Additional populations were located nearby in a similar montane habitat, from where several large clusters found on fallen, rotting branches were transplanted to the Jingdong Subtropical Botanical Garden. Occasionally, individuals of this species can be seen on sale in the open markets in Kunming City (AQH pers. observ.), ca. 300 km distant from Jingdong County. Only one small population was found in Khammouane Province, Laos, during a survey of orchids by a joint team of botanists from Kadoorie Farm & Botanic Garden (KFBG) in Hong Kong and the Biotechnology and Ecology Institute (BEI) in Laos. A few individuals were brought into cultivation at BEI. Southwest China and northern Laos, as well as neighboring parts of northern Vietnam, remain under-surveyed, and so additional populations of B. jingdongense may yet be found in the region. Nevertheless, natural vegetation in this region is intensely threatened by ongoing logging, the expansion of agroforestry plantations, mining and the construction of dams. Based on the data presently available, we estimate an Extent of Occurrence (EOO) of 5,582 km 2 and an Area of Occupancy (AOO) of 12 km 2 (based on a grid cell size of 4 km 2), using GeoCAT ( Bachman et al. 2011). All populations at the three known locations are very small, each estimated to comprise between 50–350 mature individuals, giving a total global population size of up to 1,000 mature individuals. In addition, the species is known to have undergone a decline in its area of occupancy, area and quality of habitat, as well as in the number of subpopulations and mature individuals, as a result of logging and forest clearance. Given these factors, we assess it as VU (B1&2ab(ii,iii,iv,v), D) ( IUCN 2014), while noting that monitoring of the illegal trade of this species in plant markets as well as in its natural habitat is necessary.

Taxonomic notes:— According to the sectional classification proposed by Vermeulen (2014), Bulbophyllum jingdongense is referrable to section Brachyantha (1861: 264), which includes ca. 26 species characterized by a subumbellate inflorescence, sepals and petals with entire margins, and lateral sepals that are 2–6 times as long as the dorsal sepal.