Volume 12 > Part 1 > Year 2011 > Page 262 > Orchidaceae > Sirindhornia

2. Sirindhornia monophylla (Collett & Hemsl.) H.A.Pedersen & Suksathan

Nord. J. Bot. 22: 395, fig. 3–4. 2003; Sitthisajjadham, Wild Orchids Thail. [in Thai]: 408. 2006; Orchid Guide Book 2 [in Thai]: 74 (bottom right), 159. 2007; Nanakorn & Watthana, QSBG (Thai Native Orchids 2): 34. 2008.— Habenaria monophylla Collett & Hemsl., J. Linn. Soc., Bot. 28: 134. 1890; Hook.f., Fl. Brit. India 6: 143. 1890.— Ponerorchis monophylla (Collett & Hemsl.) Soó, Acta Bot. Acad. Sci. Hung. 12: 353. 1966; Seidenf., Nord. J. Bot. 5: 157. 1985; S.C.Chen et al. in Z.Y. Wu et al. (eds), Fl. China 25: 94. 2009. [For additional synonyms, see H.A. Pedersen et al., Nord. J. Bot. 22: 395. 2003). Fig. 154; Plate XXI: 4.

Accepted Name : This is currently accepted.

Description : Flowering shoots 12–40 cm tall. Foliage leaf (broadly) elliptic to (ob)ovate, 2.4–11.5 by 1.8–5.4 cm. Inflorescence 7-to many-flowered; bracts lanceolate to triangular-ovate, (sub) acute to acuminate, 1- to 3-veined from the base, 4.2–16 by 1.7–3.5 mm. Sepals (sub)glabrous; dorsal sepal 2.8–4.5 by 1.5–2.6 mm; lateral sepals slightly spreading, 3.5–4.8 by 1.6–2.8 mm. Petals connivent with the dorsal sepal, (ovate-)oblong, slightly oblique, rounded to truncate, glabrous or somewhat ciliate, 2-veined (rarely 3-veined) from the base, 3–4.7 by 1.4–2.3 mm. Labellum more or less obtriangular, somewhat three-lobed in its distal part (incisions 1–2.3 mm deep), rose-coloured to white with numerous tufts of purple papillae on the ventral side, 3.4–6.8 by 4.1–8.4 mm; side lobes rounded to nearly truncate; midlobe truncate to rounded; spur slightly downcurved, cylindric, often slightly widened towards the rounded apex, 4.5–7.7 mm long. Column clavate, 1.5–2.8 mm long; pollinia with separate viscidia. Ovary 5–10.9 mm long.

Thailand : NORTHERN: Tak (Doi Hua Mot).

Distribution : Myanmar (type), Yunnan.

Ecology : Scrub and open grassy slopes on limestone; ca 1,000 m alt. Flowering: May–June.

Vernacular : Ueang si ak kha ne (เอื้องศรีอาคเนย์).

Notes: Thorough autecological information on Sirindhornia monophylla can be found in Srimuang et al. (2010a, 2010b). The hybrid S. mirabilis × monophylla has been recorded from Doi Hua Mot where the parental species occur sympatrically (Pedersen & Ormerod, 2009).