Volume 12 > Part 1 > Year 2011 > Page 39 > Orchidaceae > Cheirostylis

8. Cheirostylis yunnanensis Rolfe

Bull. Misc. Inform. Kew 1896: 201. 1896; Seidenf., Dansk Bot. Ark. 32(2): 71, fig. 42. 1978; Opera Bot. 114: 35. 1992; N.Pearce & P.J.Cribb, Fl. Bhutan 3(3): 82. 2002; S.C.Chen et al. in Z.Y. Wu et al. (eds), Fl. China 25: 61. 2009; Sitthisajjadham & Tripetch, Wild Orchids Thail. 2 [in Thail: 142. 2009. Fig. 20.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Flowering shoots 9–25(–37) cm tall. Foliage leaves 4–6, placed in a basal rosette; lamina elliptic to lanceolate, acute, 0.9–5 by 0.5–2.4 cm (lamina of longest leaf 1.5–5 cm long). Inflorescence glandular-pubescent; rachis 0.7–4.5(–6) cm long, 2- to 10-flowered (rarely up to 15-flowered); bracts ovate-lanceolate to narrowly triangular, acuminate, 1-veined, glandular pubescent on the dorsal surface, 3.6–5.5 by 2–2.5 mm. Flowers short-pedicelled, mainly light green with greenish-white petals and white labellum with a yellow spot. Synsepal (sparsely) glandular-pubescent, 4.9–6.5 mm long. Petals adnate to the synsepal in nearly their whole length (apices free), porrect to slightly incurved, obliquely to falcately linear-oblanceolate, obtuse to rounded, 4.6–8.3 by 1–2 mm. Labellum 4.8–8.5 mm long along the mid-line; hypochile inside with a short row of 2–4(–5) papilla-like appendages on either side; epichile cleft for half to three fourths of its length to form two subsimilar, coarsely dentate lobules (each 2.5–7 by 2.5–7 mm). Column 2.8–2.9 mm long; stylids obliquely linear-lanceolate, subequal to the rostellum; anther acute to acuminate in front, 2–2.4 mm long. Ovary (including pedicel) (sparsely) glandular pubescent, 7.1–8.3 mm long. Capsule suberect, short-pedicelled, obpyriform, sparsely glandular pubescent, 0.6–0.9 cm long, 0.3–0.5 cm in diameter.

Thailand : NORTHERN: Chiang Mai (Queen Sirikit Botanic Garden), Tak (Doi Hua Mot); NORTH-EASTERN: Khon Kaen (Pha Nok Khao), Loei; SOUTH-WESTERN: Kanchanaburi, Prachuap Khiri Khan (Huai Yang); PENINSULAR: Ranong (Ngao Falls).

Distribution : NE India, Myanmar, S China (type), Vietnam.

Ecology : Terrestrial in seasonal evergreen forests, tropical rain forests and bamboo thickets on limestone or (less frequently) granite bedrock: 100–800 m alt. Flowering: November January.

Vernacular : Ueang din pak pat yunnan (เอื้องดินปากพัดยูนนาน).

Notes: I have seen no herbarium specimen of Cheirostylis yunnanensis from Loei; the above record from this province is based on Sitthisajjadham & Tripetch (2009: 142).

Sitthisajjadham (2007) reported Cheirostylis chinensis Rolfe and C. flabellata Wight as new to Thailand (see also Sitthisajjadham & Tripetch, 2009: 139 concerning C. chinensis). According to S. Sitthisajjadham (in litt. to K. Srimuang), the finds were made in Amphoe Suan Pheung (Ratchaburi) and Khao Luang National Park (Nakhon Si Thammarat), respectively. In both cases, however, no herbarium specimen is available, and judging from the published photos, the plants in question may equally well represent forms of the highly variable C. yunnanensis. Thus, further documentation is needed before C. chinensis and C. flabellata can be counted as members of the flora of Thailand.