Volume 12 > Part 2 > Year 2014 > Page 317 > Orchidaceae > Acriopsis

3. Acriopsis ridleyi Hook.f.wfo-0000414856

Fl. Brit. India 6: 79. 1890; Holttum, Revis. Fl. Malaya, ed. 2: 556. 1957; Seidenf. & J.J.Wood, Orchids Penins. Malays. Singap.: 563, fig. 257a–b. 1992. Plate XXV: 4.

Accepted Name : This is currently accepted.

Description : Pseudobulbs ellipsoid to fusiform, slightly furrowed, covered with sheaths, 1.5–3.5 by 0.6–1.1 cm; without erect catch-roots. Foliage leaves 1–2 per pseudobulb, linear, acute to obtuse, thin-textured, glabrous, 4.5–15 by 0.3–0.6 cm. Inflorescences racemose, lax, 12- to many-flowered, glabrous; peduncle 10.4–22 cm long; rachis 8–19.5 cm long; bracts triangular, minute, ca 1 mm long, glabrous. Flowers: pedicel (including ovary) 5–10 mm long. Sepals glabrous, pale yellowish-green with purple markings, oblong, acute to rounded, margin slightly involute; dorsal sepal boat-shaped, 6.7–8 by 2.2–2.4 mm; synsepal boat-shaped, 6.8–8 by 2.2–2.6 mm. Petals spreading, glabrous, pale yellow with purple markings, obovate, slightly oblique, rounded, 4.8–6.6 by 3.1–3.2 mm. Labellum 3-lobed, white with pink calli; side lobes obliquely oblong, rounded to subtruncate, 1.4–1.6 by 1–1.5 mm, margins slightly wavy, spreading; mid-lobe broadly spathulate, 2.5–2.9 by 2.5–2.6 mm, rounded, sometimes retuse, margins irregularly wavy; proximal part of labellum with a median keel that splits to form 2 parallel diskoid calli on claw of mid-lobe. Column glabrous, dark purple proximally, white distally, 3.5–4.5 mm long, hooded; stelids blunt, dark purple with translucently greenish-yellow apices, swollen at apex, 1.8–2 mm long. Capsule not seen.

Thailand : PENINSULAR: Songkhla (Chanan), Narathiwat (Tak Bai).

Distribution : Singapore (type), Peninsular Malaysia, Borneo.

Ecology : In Songkhla reported to grow on dipterocarps in coastal heath forests; habitat in Narathiwat unknown. Flowering: recorded in January, March and May.

Notes: This species is newly recorded for Thailand.