线叶石斛（新拟）
Dendrobium aurantiacum Rchb. f. in Gard. Chron. ser. 3, 2: 98. 1887——D. chryseum Rolfe in Gard. Chron. 1: 233, 1888; Seidenf. in Opera Bor. 83: 43. 1985, P. P. ——D. flaviflorum Hayata in J. Coll. Sci. Univ. Tokyo 30 (1): 312. 1911. ——D. tibeticum Schltr. in Fedde Repert. Sp. nov. 17: 1352. 1936. ——D. clavatum Lindal. var. aurantiacum (Rchb. f.) T. Tang et F. T. Wang in Acta Phytotax. 1 (1): 40, 80. 1951; 台湾兰科植物1: 122-1233 (图). 1975; 台湾植物志 5: 955. 1978.——D. chryseum Rolfe var. bulangense G. X. Ma et J. Xu in J. Pl. Resource Environ 1 (4): 64. 1992.
15a. 线叶石斛（原变种）
Epiphytic on tree trunks in high-mountain broad-leaved forests; 1700-2600 m. C Sichuan (Ebian, Emei Shan), Taiwan, NW to SE Yunnan [NE India, Myanmar].
本种在属内国产大花种类中茎是最纤细的。在英国邱植物园标本馆收藏的我国台湾标本 (J. Linsleg Gressitt 319, alt. 2400m) 与来自云南独龙江的标本完全一致。
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Stems cylindric, usually 25-35 cm, slender, 2-4 mm in diam., unbranched, with many nodes, internodes 2.5-4 cm, pale yellow or yellowish brown when dry. |
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Leaves linear or narrowly oblong, 8-10 × 0.4-1.4 cm, leathery, base sheathing, apex obtuse and emarginate or sometimes subacute and obliquely hooked; leaf sheath tightly embracing stem. |
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Inflorescence lateral on old leafless stem, ca. 1 cm, usually 1 or 2(or 3)-flowered; peduncle suberect, ca. 0.5 cm; basal sheaths 3 or 4, overlapping, pale white, cupular or tubular, papery, basal ones short, distally elongate, 5-20 mm; floral bracts pale white, cymbiform, 12-13 × ca. 5 mm, membranous, apex obtuse. Pedicel and ovary ca. 3 cm. Flowers spreading, ca. 6.5 cm wide, concolorous yellow, center a darker shade, occasionally with large purple spots on sepals and petals and a purple spot on lip disk, inner surface of lip sometimes with several red stripes. Dorsal sepal oblong-elliptic, 23-25 × 11-14 mm, 5-veined, obtuse; lateral sepals slightly obliquely oblong, ca. as long as dorsal sepal or slightly narrower, 5-veined, apex obtuse; mentum conic, ca. 6 mm. Petals elliptic or broadly elliptic-obovate, 24-26 × 14-17 mm, 3-veined, lateral major veins branched, apex obtuse; lip suborbicular, ca. 25 × 22 mm, adaxially densely pilose, both sides embracing column below middle, claw ca. 3 mm, margin irregularly denticulate, disk without markings. Column ca. 4 mm, foot ca. 3 mm; anther cap narrowly conic, ca. 4 mm, glabrous, apex subtruncate. Fl. May-Jun. |
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