Volume 12 > Part 1 > Year 2011 > Page 125 > Orchidaceae > Habenaria

29. Habenaria medioflexa Turrill

Bull. Misc. Inform. Kew 1923: 118. 1923; Seidenf. & Smitinand, Orchids Thail.: 45, fig. 33. 1959; Seidenf., Dansk Bot, Ark, 31(3): 84, fig. 48. 1977; Opera Bot. 114: 58. 1992; Seidenf. & J.J.Wood, Orchids Penins. Malays. Singap.: 111, fig. 46b–c, t. 4a. 1992; S.C.Chen & P.J.Cribb in Z.Y. Wu et al. (eds), Fl. China 25: 152. 2009; Kurzweil, Thai Forest Bull., Bot., special issue: 28. 2009. Fig. 70; Plate IX: 2.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Flowering shoots glabrous, 23–52 cm tall. Foliage leaves (3–)5–8, cauline, scattered in the lower half of the stem, elliptic-lanceolate, acute or acuminate, mucronate, 12–22 by 2–5.3 cm. Sterile bracts 3–6, spreading to erect, lanceolate, acuminate, 2.7–3.7 cm long, margins sometimes minutely denticulate. Inflorescence lax, 7- to 25-flowered; rachis 5–15 cm long; floral bracts lanceolate, acuminate, 15–32 by 3–5 mm, margins sometimes minutely denticulate. Flowers 1.7–2 cm in diameter, sepals and spur green, petals green or white, labellum white. Sepals acute or subacute; dorsal sepal erect, elliptic, 6–8 by 3–4.2 mm; lateral sepals spreading, obliquely ovate, 6–8(–10) by 3.5–5 mm, basally united with the petals and the labellum. Petals forming a hood with the dorsal sepal, oblong-lanceolate, acute, 7–7.5 by 0.6–1 mm. Labellum 12–20 by 17–20 mm, 3-lobed above a claw 2–3.8 by 1.5–2.2 mm, with a collar in front of the spur mouth; midlobe oblong, 7–10 by 0.5–1 mm; side lobes with linear laciniae 9–14 mm long; spur cylindric, 35–46 mm long, geniculate and clavate in the middle. Column 3–5 mm long; anther reflexed, anther canals ca 2 mm long; auricles prominent, subulate and as high as or higher than the anther. Ovary (including pedicel) 24–30 mm long. Capsule not seen.

Thailand : NORTHERN: Chiang Mai, Kamphaeng Phet, Nakhon Sawan; NORTH EASTERN: Loei, Nong Khai (fide Seidenf., Dansk Bot. Ark. 31(3): 84.1977); CENTRAL: Saraburi; SOUTH-EASTERN: Prachin Buri, Chanthaburi; PENINSULAR: Phangnga (Pungah – type: Hamiff & Nur 3858, holotype -SING, isotype -K).

Distribution : S China (Yunnan), Cambodia, Vietnam, Peninsular Malaysia (Kedah).

Ecology : In mixed deciduous or in evergreen forests over granite, also reported in bamboo thicket; 100–375 m alt. Flowering: August–November(–December).

Vernacular : Nang ua pak foi (นางอั้วปากฝอย).

Notes: A collection, doubtfully of this species, was also made in Lampang Province in northern Thailand.