ORCHIDACEAE
Pteroceras Hasselt ex Hassk., Flora. 25(2, Beibl.): 6 (1842).
By: Ornitharium Lindl. & Paxton; Proteroceras J.Joseph & Vajr.
Bhakta B. Raskoti
Taxon Description
Epiphytic, monopodial herbs. Stems unbranched. Leaves often distichous, apex usually unequally bilobed. Inflorescences terminal, lateral or axillary, erect or pendulous, racemose, with spiral or distichous flowers. Flowers often resupinate. Sepals and petals free, spreading; lateral sepals often oblique and distinctly broader than petals. Petals narrower than sepals; lip attached to column foot, 3-lobed; lateral lobes erect; mid-lobe fleshy, base spurred or saccate. Column stout; rostellum 2-lobed; pollinia 2, subglobose, stipe suboblong, viscidium triangular; stigma rounded. Fruit oblong.
Taxon Statistics
Worldwide 22 species, in Assam-Burma, South Asia, East Asia, East Himalaya, South East Asia and W Himalaya. One species in Nepal.
1. Pteroceras teres (Blume) Holttum, Kew Bull. 14: 271 (1960).
Dendrocolla teres Blume, Bijdr. Fl. Ind.: 289 (1825); Aerides teres (Blume) Lindl.; Pteroceras radicans Hassk.; Sarcochilus teres (Blume) Rchb.f.; Thrixspermum teres (Blume) Rchb.f.
Plant 19–25 cm tall. Stem unbranched, 4–5 cm; noded. Leaves obliquely linear-oblong, 12–15 × 2–2.5 cm, apex unequally 2-lobed. Inflorescences racemose, 4–5 cm; peduncle sheathed, sheaths 1.5–2 × 2 mm; rachis 14–18 cm, winged at node, up to 25-flowered. Floral bracts semi-elliptic, 1.5–2 × 2 mm, apex obtuse. Flower sepals and petals yellow with reddish-brown spots, lip yellow, resupinate, 5–9 mm across. Pedicel and ovary 5–7 mm. Dorsal sepal obovate, 4–6 × 2–4 mm, apex obtuse. Lateral sepals adnate to the column foot, obliquely obovate, 4–6 × 2–4 mm, apex rounded. Petals obovate-spathulate, 4–5 × 1.5–4 mm, apex obtuse. Lip 3–5 mm, 3-lobed, spurred; lateral lobes linear-oblong, 1–2 × 0.5–1 mm, apex subacute; mid-lobe oblong (in general outline), 3–5 mm, rugose-papillose, callus near the spur entrance; callii 2. Spur infundibulifrom, ca. 3 mm. Column 1–2 mm. Fruit not seen.
Distribution: Nepal, Assam-Burma, E Asia, E Himalaya, SE Asia and W Himalaya.
Altitudinal range: 400–1000 m.
Ecology: Broad-leaved forests.
Flowering: June. Fruiting: August–October.