柱根姜 zhu gen jiang

Rhizomes cylindric, aromatic. Pseudostems 60--100 cm × 6--10 mm, base with green sheaths. Ligule 2-lobed, 2--4 mm, pubescent, lobes rounded at apex; petiole ca. 2 mm; leaf blade narrowly lanceolate, 18--25 × 3--4 cm, glabrous except sparsely puberulent along midvein abaxially, base cuneate, apex acuminate or caudate. Inflorescences arising from rhizomes, ellipsoid or narrowly so, 4.5--5 × 2--3 cm; peduncle embedded in ground, 6--12 cm, slender; bracts elliptic or narrowly so, 3--4 × 1--2 cm, glabrous except red pubescent at acute or acuminate apex; bracteoles red with white base, tubular, 2.5--2.8 cm. Calyx 1.4--1.6 cm, apex obscurely 3-toothed. Corolla tube yellow, 4--5 cm; central lobe lanceolate, 2.6--3 × 0.9--1 cm; lateral lobes 2--2.2 cm × 5--7 mm. Labellum yellow at base; lobes purple with yellow stripes, central one obovate, 1.8--2 × 1.1--1.3 cm, apex acuminate, lateral ones auriculate, small. Anther sessile, ca. 1.1 cm; connective appendage yellow proximally, purple distally, ca. 1 cm. Ovary densely white pubescent. Capsule (immature) white with purple or white apex, oblong, ca. 5 × 1.8 cm, 3-angled. Seeds subobovoid, ca. 5 mm; aril white. Fl. Oct.

Forests; ca. 1200 m. SW Yunnan (Menglian Dai-Lahu-Va Zu Zizhixian) [N Thailand].