15/06/2014

Loài lan mới ở bắc Việt Nam Gastrochilus kadooriei

Gastrochilus kadooriei Kumar, S.W.Gale, Kocyan, G.A.Fisch. & Aver. sp. nov. (Theo: Phytotaxa)

Phytotaxa 164 (4): 276–280 
Description: Lithophytic herbs, prostrate, apex ascending, 3–30 cm tall. Roots vermiform, slender, up to 10.0 cm long, 1.5–1.8 mm in diameter. Stem rarely branched, up to 30.0 cm tall, 1.5–2.0 mm in diameter, covered with sheathing leaf bases, green, glabrous, ridged and woody towards the base, herbaceous towards the apex; internodes of stem 5–6 mm long. Leaves alternate, distichous, green, ovate, 1.3–1.8 ×5.0–6.0 mm, margin finely serrate towards upper quarter; leaf apex aristate with a smaller lateral tooth on either side, median aristae 1.5–3.0 mm long, lateral teeth less than 1.5 mm long (teeth shorter in older leaves); leaf base amplexicaul, sometimes with tiny red-purple spot only on young shoots. Inflorescence a raceme, 1 or 2, pendulous, thick (1.5 mm in diameter) green, up to 1 cm long, 1–3-flowered; peduncle 9 mm long. Flowers 9 ×9 mm, pale yellow, petals and sepals with red-brown spots. Pedicel and ovary 5.0–5.2 mm long, green at base, reddish-green towards the apex. Sepals and petals 1-veined, margins entire, thicker towards middle; dorsal sepal obovate, 3.5 ×2.0 mm; lateral sepals obliquely obovate, 3.5 ×2.2 mm; petals obovate, 3.0 ×1.7 mm. Labellum 4.0–4.2 ×5.0 mm, glabrous; hypochile attached to the base of column wings, saccate, 4.2–4.5 ×3.0–3.5 mm, with an obscure median ridge giving a roughly scrotiform appearance from the front, ecallose, margin entire, reddish towards attachment with column, yellow elsewhere; epichile projecting forwards, triangular with rounded corners, slightly concave, around 1/3 the height of hypochile, 1.6 ×1.6 mm, yellow with some red-brown spots at the front. Column rounded at back, flat in front, 2.0 mm long, 1.4 mm thick, 1.6 mm wide; anther cap copular, with two chambers, trapezoid, 1.5 ×1.3 mm, with a beak on the front that partly covers the stipe; pollinarium 1.7–1.9 mm long; pollinia 2, yellow, bilobed, 0.6 ×0.5 mm, almost hemispheric with a depression at the centre; stipe elongate, obovate, 0.8 mm long; viscidium thicker and broader than the stipe, elliptic, 0.3 ×0.1 mm, sticky, yellowish; rostellum inverted L-shaped, 1.8 mm long, yellow, forked apically with rounded tips, arising from the centre of horseshoe-shaped clinandrum, hanging in front of the stigma without touching the stigmatic surface; stigma deeply seated, almost triangular in outline with rounded corners.
Habitat:—In Hong Kong, plants grow on moss-covered granite rocks and boulders in seasonal streams with leaves devoid of or with faint purple spots. In Vietnam, plants are found on limestone rocks and may reach up to 30 cm or more tall and, if in bright sunlight, have purple spots on the leaves. In both places, plants grow only loosely attached to the rock surface. As they are found near streams, they seem to be highly vulnerable to flash flooding.
Distribution:—Southwestern China (Yunnan), Hong Kong, Laos and Vietnam. The species is also likely to occur in intervening and adjacent areas. In addition to the Yunnan specimens cited above, we suspect that the image in Xu et al.(2009: 476, plate 695a) labeled as Gastrochilus pseudodistichus is probably referable to G. kadooriei. The growth habit, flower colour, and morphology of the stem/leaves are a close match for the species. There is one more photographic record of the species, Averyanov et al. HAL 8441(Averyanov pers. comm.), from Vietnam, Ha Giang, Yen Minh, Lao Va Chai, vicinity of Chi Sang village
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