Bulbophyllum nigrescens Rolfe 1910 SECTION Hirtula Ridley 1908
Photos by Manorot Tangsaveepha Copyright ©, and the Butterfly and Orchids Photo Gallery
Plant and Flowers in situ as Lithophyte
Plant and Flowers in situ as Epiphyte
Photos by Copyright ©, Andre Schuiteman, Dr. E.F. de Vogel and Jaap Vermeulen and the Their Netherlands National Herbarium Website
LATE
EARLY 
Common Name The Blackish Bulbophyllum - In China Gou Geng Shi Dou Lan
Flower Size 3/8" [1 cm]
Found in Thailand, Yunnan Province of China and Vietnam in sparse woods growing on tree trunks at elevations around 400 to 1500 meters as a miniature sized, warm to cool growing lithophye or epiphyte with .24 to 1" [.6 to 2.5 cm] between each squat, ovoid or low-conical, flattened ventrically, rugose pseudobulbs carrying a single, apical, linear to lanceolate leaf that blooms in the late winter and early spring on an erect, basal, peduncle 3.2 to 8.8" [8 to 22 cm] long, provided with 5 bracts, rachis not thickened, 3.6 to 8" [9 to 20 cm] long, glabrous, 9.2" to 17.6" [23 to 44 cm] long, successively many, 13 to 27 flowered inflorescence with triangular, acuminate, shorter than the ovary floral bracts.
Some authors cite B anguste-ellipticum as a synonym but I feel there are distinct differences other than color.
Synonyms
References W3 Tropicos, Kew Monocot list , IPNI ; The Orchids of Thailand Seidenfaden & Smitinand 1961 drawing/photo fide; The Orchids of Thailand Seidenfaden & Smitinand 1965 corrections; Dansk Botanisk Arkiv Bind 33 #3 Orchid Genera in Thailand VIII Bulbophyllum Thou Seidenfaden 1979 drawing fide; Identification of the Orchids [Orchidaceae Juss.] Vietnam Averyanov 1994; Wild Orchids of China Tsi, Chen Mori 1997 photo good; Native Orchids of China in Colour Singchi, Zhanhuo and Yibo 1999 photo fide; Bulbophyllum and Their Allies Siegerist 2001; Gard. Bull. Singapore 54: 143 J J Verm. 2002 drawing/photo fide; A field Guide to the Wild Orchids of Thailand Vaddhanaphuti 2005 photo fide; Flora of China 25: 404–440. 2009; A Field Guide to the Orchids of China Singchi, Zhongjian, Yibo, Xiaohua and Zhanhuo 2009 photo fide; Flora of China Vol 25 Zhengyi, Raven & Deyuan 2009; Flora of China Vol 25 Illustrations Zhengyi, Raven & Deyuan 2010 drawing ok; The Wild Orchids in Yunnan Xu Xiang Ye & Liu 2010 photos fide; A to Z of South East Asian Orchid Species Vol 2 O'Byrne 2011 photo fide; Atlas of Native Orchids of China Vol 2 Jin Xiaohua, Li Jianwu and Ye Deping 2019 photo fide;
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