4. B. forrestii Seidenfaden (1973: 120, 1979: 165); Chen et al. (2009: 428); Averyanov et al. (2015: 145).

≡ Cirrhopetalum aemulum Smith (1921: 195) . Syntypes:— CHINA, Yunnan, 1 June 1923, G . Forrest, 17970 (MNHN-P-P00348028 photo!) http://coldb.mnhn.fr/catalognumber/mnhn/p/p00348028). CHINA, Yunnan, 1917, G . Forrest, 17970 (K000867021 photo! http://specimens.kew.org/herbarium/ K000867021). CHINA, Yunnan, Shweli Valley, June 1912, G . Forrest 8130 (K000867022 photo! http://specimens.kew.org/herbarium/ K000867022). MYANMAR: 17 May 1914, F . Kingdon Ward, 1554 (E00743063 photo! https://data.rbge.org.uk/herb/ E00743063) .

≡ Rhytionanthos aemulum (W.W.Sm.) Garay, Hamer & Siegerist (1994: 637) .

Habitat and phenology: —Dry broad-leaved primary and secondary evergreen and semideciduous forest at elevations 500–1000 m a.s.l. Creeping epiphyte. Flowering in March.

Distribution: — India, Myanmar, China, Thailand, Lao, Vietnam (doubtful).

Notes: —According to Seidenfaden (1973) Bulbophyllum forrestii looks similar to B. helenae but actually the median sepal of true B. forrestii is slightly erose to almost entire (vs. irregular erose to denticulate), lip adaxially papillose (vs. smooth in B. helenae).

Studied specimens:— CHINA, Yunnan, in the Shweli Valley, June 1912, Forrest G. 8130 (K000867022 photo!) . CHINA, Yunnan, 1917, Forrest G. 17970 (K000867021 photo!) . CHINA, Yunnan, 1923, Forrest, G. 17970 (P00348028 photo!) . LAOS, Xiangkhouang Province, Peak District, Oran Village, around point 19°38′53″N 103°23′12″E, primary and secondary broad-leaved evergreen dry forest on shale sandstone slopes and along ridge edge at elevation about 1750–1850 m a.s.l., epiphyte on tall mossy tree along ridge edge, not rare, 2 April 2015, N. T. Hiep et al., LA-VN 931b / TM 1225 (LE01055537 http://en.herbariumle.ru/?t=occ&id=18092, LE01073555 http://en.herbariumle.ru/?t=occ&id=18088 photo) .