串珠石斛 chuan zhu shi hu

Callista falconeri (Hooker) Kuntze; Dendrobium erythroglossum Hayata.

Stems pendulous, cylindric, 30-40 cm or longer, slender, 2-3 mm in diam., fleshy, many branched, often swollen at branched nodes and moniliform, internodes often dilated above middle, to 3.5 cm on main stem, to 1 cm on branches, brownish yellow when dry, sometimes tinged with dirty black. Leaves often 2-5, alternate on upper part of branches, narrowly lanceolate, 5-7 × 0.3-0.7(or more) cm, leathery, base sheathing, apex obtuse or acute and slightly hooked; leaf sheath usually pale pink, tubular, papery. Inflorescences lateral, 1-flowered from each peduncle (occasionally a second peduncle arising creating a 2-flowered inflorescence); peduncle 5-15 mm, slender; basal sheaths 1 or 2, tubular, membranous; floral bracts white, ovate, 3-4 mm, membranous. Pedicel green; ovary yellowish green with purplish red spots, ca. 1.5 cm, slender. Flowers spreading, large, thinly textured; sepals pale purple or red with deep purple tip, petals white with purple apex, lip white with purple tip, yellow on both sides at base, disk with a deep purple blotch, column foot pale red, anther cap creamy white. Dorsal sepal ovate-lanceolate, 30-36 × 7-8(or more) mm, 8- or 9-veined, base slightly contracted, apex acuminate; lateral sepals ovate-lanceolate, ca. as large as dorsal sepal, 8- or 9-veined, base oblique, apex acuminate; mentum subglobose, ca. 6 mm. Petals ovate-rhombic, 29-33 × 14-16 mm, main veins 5 or 6, secondary veins many, base cuneate, apex subacute; lip ovate-rhombic, ca. as long as petals but much wider, adaxially densely barbellate, margin denticulate, apex obtuse or slightly acute. Column ca. 2 mm; foot ca. 6 mm; anther cap subconic, ca. 2 mm, densely bristly, front margin lacerate, apex broadly obtuse and concave.

Lithophytic on rocks in valleys or epiphytic on tree trunks in dense forests; 800-1900 m. E and N Guangxi (Lingchuan, Lingui), SE Hunan (Zixing), W Taiwan (Jiayi to Miaoli), SE to W Yunnan [Bhutan, NE India, Myanmar, N Thailand, Vietnam].

The Taiwanese form has consistently concolorous flowers with pink sepals and petals.