锯尾钻柱兰 ju wei zuan zhu lan

Stems elongate, 6-7 mm in diam. Leaves elliptic-oblong, 3-4 × 1-1.5 cm, obtuse, unequally bilobed. Inflorescence short, 2-6-flowered; floral bracts ovate-triangular, ca. 1.5 mm. Flowers pale yellow, sepals with purplish red veins, disk yellow and spotted purplish red, spur white, apex tinged pale yellow; pedicel and ovary 7-8 mm. Dorsal sepal broadly elliptic, concave, ca. 6.5 × 4.5 mm, with 5 purplish red veins, obtuse; lateral sepals similar to dorsal sepal, 7-veined. Petals oblong, ca. 5 × 3 mm, apical margin ± irregularly denticulate; lip fleshy, 3-lobed; lateral lobes erect, subovate-triangular, obtuse; mid-lobe subcordate, ca. 4 × 5 mm, margin white ciliate, apex shortly cuspidate; disk thickened and cushionlike centrally, waxy; spur ca. 4 × 2 mm, interior with a longitudinal broad ridge almost dividing spur into 2 halves, and with an elliptic appendage on back wall. Column ca. 2 mm, with tufted white hairs on both sides at base. Fl. Aug. 2n = 38.

Lithophytic on rocks and epiphytic on tree trunks in broad-leaved evergreen forests; ca. 700 m. S Yunnan [Cambodia, Laos, Thailand, Vietnam].