Bulbophyllum mengyuanense Q.Liu, J.W.Li & X.H.Jin, 2015

Liu, Qiang, Li, Jian-Wu, Jin, Xiao-Hua & Gao, Jiang-Yun, 2015, A new species of Bulbophyllum (Orchidaceae; Epidendroideae; Dendrobiinae) from Yunnan, China, Phytotaxa 236 (3), pp. 287-290 : 287-289

Bulbophyllum mengyuanense Q.Liu, J.W.Li & X.H.Jin , sp. nov. ( Figs. 1 , 2 )

Type:— China. Yunnan: Mengla County, Mengyuan Town, limestone forest, 1000 m, 7 Oct. 2010, Li 1099 (holotype, HITBC!).

Diagnosis: Bulbophyllum mengyuanense is similar to B. drymoglossum and B. hainanense , but can be distinguished from them by having yellow flowers with purple stripes, lateral sepals connate in their basal third, conspicuous column stelids and a labellum without a callus.

Epiphytic herbs. Rhizome creeping, slender, with internodes about 1 cm, each node bearing 1 leaf and 2–3 roots. Pseudobulb reduced to nearly absent. Leaf subsessile, elliptic, 13.0 × 8.5 mm, apex acuminate. Inflorescences arising from base of the reduced pseudobulb, erect, 31 mm, with 1 sheath, solitary flowered; floral bracts ovate, 1.3–3.0 mm, apex acute. Pedicel and ovary 8 mm. Flowers yellow, veins purple. Dorsal sepal ovate-oblong, 10 × 4 mm, apex acuminate, triveined; lateral sepals slightly larger, ovate-oblong, 12.0 × 4.5 mm, apex acuminate, connate in basal 1/3, 3-veined; petals oblong, 4.5 × 1.8 mm, entire, obtuse, univeined; lip elliptic, 5 × 4 mm, triveined, base attached to end of column foot by a mobile joint, apex obtuse; column stout, 2× 1 mm, column-wing oblique triangular, 1.1 × 0.8 mm; column foot 4.5–5.0 mm, swollen in the middle, anther cap glabrous, pollinia 2.

Distribution:— Mengla, Yunnan, China (close to the border with Laos).

Ecology:— Epiphytic on trees in the limestone forest, which mainly is composed of Pterospermum proteum ( Sterculiaceae ), Pistacia weinmannifolia ( Anacardiaceae ), Cleistanthus sumatranus ( Euphorbiaceae ), Quercus yiwuensis ( Fagaceae ), Tetrameles nudiflora ( Tetramelaceae ) ( Wang et al. 1997).

Phenology:— Flowering from October to November.

Conservation status:— At present, Bulbophyllum mengyuanense is known from two sites, and just two populations were discovered during four years of botanical surveys. However, it is expected that more populations may be found by thorough botanical investigation in the vicinity of the limestone forest. Moreover, it is possible that other populations occur in similar limestone habitats in the Laos and Myanmar. Therefore, it is premature to conduct a full conservation assessment based on the two known population. We regard the species as Data Deficient (DD: IUCN 2012).

Etymology:— Named for Mengyuan town in Xishuangbanna Autonomous Prefecture, Yunnan Province, where the type was collected.

Additional specimens examined:— China. Yunnan Province, Mengla County, Mengyuan town, Xishuangbanna Autonomous Prefecture , limestone forest, 1000 m, 7 Oct. 2010, Li 1099 ( HITBC!) ; Paozhuqing , epiphytic on tree, 1100 m, 18 Oct. 2008, Jin 9457 ( PE!) .

Taxonomic notes:— The inconspicuous psudobulbs of this new species and the type of inflorescence indicate that this species belongs to sect. Stachysanthes . Morphologically, the new species is similar to B. drymoglossum Maximowicz ex Okubo (1887: 14) ( Tsi 1999, Chen et al. 2009), B. hainanense Z.H. Tsi (1982: 118) ( Tsi 1999, Chen et al. 2009) and B. hymenanthum J.D. Hooker (1890: 767) (Seidendafen 1979, Saha et al. 1980). However, this new species is characterized by having yellow flowers with purple stripes, lateral sepals basally fused and obliquely triangular column stelids; it differs from B. drymoglossum by yellow color of flower and conspicuous column stelids, from B. hainanense by the lip without callus (the labellum has at the base one pair of calli in B. hainanense ) and from B. hymenanthum by the yellow flowers and elliptic lip (the flower is white with purple stripes and the lip is elliptic with a rounded apex in B. hymenanthum ).

Figures

FIGURE 1. Bulbophyllum mengyuanense. A. Plant. B. Front view of flower. C. Lateral view of flower. D. Lateral view of column and column foot. E. Column wing. F. Anther cap. G. Pollinia.All drawn by B.Pan from the holotype, Li 1099 (HITBC).

FIGURE 2. Bulbophyllum mengyuanense. A. Habitat. B. Front view of flower. C. Lateral view of flower. D. Plant (Photo by Q. Liu).