景洪石斛  转到中国兰科植物志

Dendrobium exile  分类来源:中国植物志

景洪石斛(植物分类学报) 

Dendrobium exile Schltr. in Fedde Repert. Sp. Nov. 2: 85. 1906; Z. H. Tsi in Acta Phytotax. Sin. 18 (4): 435. 1980; Seidenf. in Opera Bot. 83: 187, fig. 128. 1985: Averyanov, Vasc. Pl. Syn. Vietnam. Fl. 1: 71. 1990; Seidenf., l. c. 114: 243. 1992; Averyanov, Iden. Guide Vietnam. Orch.: 212. 1994. 

in situ

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Epiphytic on tree trunks in open forests; 600-800 m. S Yunnan (Jinghong, Mengla) [Thailand, Vietnam].

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Stems erect, upper part branched, cylindric, to 50 cm, slender, ca. 3 mm in diam., 2 or 3 internodes above base dilated and fusiform; dilated portion of stems ca. 4.5 cm, ca. 8 mm in diam., fleshy, with 4 ribs, with pale white membranous sheaths when young, reddish brown and glossy when old. 

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 Leaves often alternate on upper part of branches, erect, terete, 2.5-6 × 1.5-2.5(or more) cm, base with leathery sheaths, apex acute.

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 Inflorescence axillary on leafy older stems, 1-flowered, up to 4 flowers open at once per stem; floral bracts ovate, ca. 2 mm. Pedicel and ovary ca. 1 cm, slender. Flowers spreading, white, inner surface of lip lateral lobes with a few pale purple spots, disk yellow. Dorsal sepal sublanceolate, ca. 17 × 2.5 mm, 5-veined, long acuminate; lateral sepals similar to and ca. as large as dorsal sepal; mentum rigid, ca. 1 cm, acute. Petals similar to sepals, ca. 17 × 1.5 mm, 3-veined; lip cuneate at base, 3-lobed above middle; lateral lobes obliquely subovate-triangular, front margin undulate, apex obtuse; mid-lobe narrowly oblong, margin undulate, apex acute; disk sparsely villous, with 3 thick and stout keeled ridges from base to apex. Column ca. 2 mm, foot with a basal callus; anther cap conic. Flowering October-November.

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Capsule fusiform, ca. 4 × 0.6 cm.

 

 

 

Fruiting November-December.




 



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