曲茎石斛Dendrobium flexicaule Z. H. Tsi

别名：曲茎石槲;曲轴石斛;

科名：兰科 Orchidaceae

属名：石斛属 Dendrobium

《中国植物志》第19卷119页
  45. 曲茎石斛（植物研究）图版18：4-6
  Dendrobium flexicaule Z. H. Tsi, S. C. Sun et L. G. Xu in Bull. Bot. Res. 6 (2): 113-116 (fig.). 1986.
  茎圆柱形，稍回折状弯曲，长6-11厘米，粗2-3毫米，不分枝，具数节，节间长1-1.5厘米，干后淡棕黄色。叶2-4枚，二列，互生于茎的上部，近革质，长圆状披针形，长约3厘米，宽7-10毫米，先端钝并且稍钩转，基部下延为抱茎的鞘；花序从落了叶的老茎上部发出，具1-2朵花；花序柄长1-2厘米，粗约1毫米，基部被3-4枚长2-4毫米的膜质鞘；花苞片浅白色，卵状三角形，长约3毫米，先端急尖；花梗和子房黄绿色带淡紫，长3-4.5厘米；花开展，中萼片背面黄绿色，上端稍带淡紫色，长圆形，长28毫米，中部宽8毫米，先端钝，具5条脉；侧萼片背面黄绿色，上端边缘稍带淡紫色，斜卵状披针形，与中萼片等长而较宽，先端钝，具5条脉，萼囊黄绿色，圆锥形，长约8毫米，宽10毫米，末端近圆形；花瓣下部黄绿色，上部近淡紫色，椭圆形，长约25毫米，中部宽13毫米，先端钝，具5条脉；唇瓣淡黄色，先端边缘淡紫色，中部以下边缘紫色，宽卵形，不明显3裂，长17毫米，宽14毫米，先端锐尖，基部楔形，上面密布短绒毛，唇盘中部前方有1个大的紫色扇形斑块，其后有1个黄色的马鞍形胼胝体；蕊柱黄绿色，长约3毫米；蕊柱足长约10毫米，中部具2个圆形紫色斑块并且疏生上部紫色而下部黄绿色的叉状毛，末端紫色、与唇瓣结合而形成强烈增厚的关节；蕊柱齿2个，三角形，基部外侧紫色；药帽乳白色，近菱形，长约2.5毫米，基部前缘具不整齐的细齿，顶端深2裂，裂片尖齿状。花期5月。
  产河南（地点不详）、湖北（神农架地区）、湖南东部（衡山南岳）、四川南部（甘洛）。生于海拔1200-2000米的山谷岩石上。模式标本采自四川（甘洛）。

《Flora of China》 Vol. 25 (2009)
Dendrobium flexicaule  Z. H. Tsi S. C. Sun & L. G. Xu, Bull. Bot. Res., Harbin. 6(2): 113. 1986.
曲茎石斛   qu jing shi hu
?Dendrobium henanense J. L. Lu & L. X. Gao.
Stems cylindric, slightly upcurved, 6-11 cm, 2-3 mm in diam., unbranched, with several nodes, internodes 1-1.5 cm, pale brownish yellow when dry. Leaves 2-4, alternate on upper part of stem, oblong-lanceolate, ca. 3 × 0.7-1(or more) cm, subleathery, base decurrent into clasping sheaths, apex obtuse and slightly hooked. Inflorescences on old stems after leaves have fallen, 1- or 2-flowered; peduncle 1-2 cm, ca. 1 mm in diam.; basal sheaths 3 or 4, 2-4 mm, membranous; floral bracts pale white, ovate-triangular, ca. 3 mm, apex acute. Pedicel and ovary yellowish green, tinged with pale purple, 3-4.5 cm. Flowers spreading; dorsal sepal yellowish green abaxially, upper part slightly tinged with pale purple; lateral sepals yellowish green, upper distal margins tinged with pale purple, mentum yellowish green; petals: lower part yellowish green, upper part pale purple; lip pale yellow, front margin pale purple, margin purple below middle, disk with a large purple flabellate blotch at middle front part, callus yellow; column yellowish green, stelidia purple at base on outside, foot with 2 rounded purple spots, lower part yellowish green, apex purple, anther cap creamy white. Dorsal sepal oblong, ca. 28 mm, ca. 8 mm wide at middle, 5-veined, apex obtuse; lateral sepals obliquely ovate-lanceolate, ca. as long as dorsal sepal and broader, 5-veined, obtuse; mentum conic, ca. 8 × 10 mm, nearly rounded. Petals elliptic, ca. 25 mm, ca. 13 mm wide at middle, 5-veined, apex obtuse; lip broadly ovate, ca. 17 × 14 mm, adaxially densely pubescent, rear part with a saddle-shaped callus, base cuneate, margin inconspicuously 3-lobed, apex acute. Column ca. 3 mm, foot ca. 10 mm, sparsely covered with bifid hairs, upper part of hairs purple; column teeth 2, deltoid; anther cap subrhombic, ca. 2.5 mm, basal front margin with irregular teeth, apex deeply bilobed, lobes sharply toothed.
● Lithophytic on rocks in mountain valleys; 1200-2000 m. Henan, Hubei (Shennongjia), E Hunan (Heng Shan), SC Sichuan (Ganluo).