37. Calanthe arcuata Rolfe, Bull. Misc. Inform. Kew. 1896: 196. 1896.
弧距虾脊兰 hu ju xia ji lan
Calanthe arcuata var. brevifolia Z. H. Tsi; C. caudatilabella Hayata; C. caudatilabella var. latiloba F. Maekawa ex Yamamoto.
Plants 18-45 cm tall. Rhizome inconspicuous. Pseudobulbs conic, small, ca. 1 cm in diam., with 2 or 3 sheaths. Leaves 3 or 4, basal, well developed at anthesis, not deciduous; blade narrowly elliptic-lanceolate or narrowly lanceolate, 15-28 × 0.7-3 cm, apex acute or acuminate; petiole-like base sheathing, often forming a pseudostem 2-3 cm. Scapes 1 or 2, arising from leaf axil, erect, 30-50 cm, densely puberulent or glabrous; rachis 10-25 cm, laxly ca. 10-flowered; floral bracts persistent, herbaceous, narrowly lanceolate, 10-18 mm, glabrous. Flowers white to yellowish green, flushed reddish brown on outer surfaces; pedicel and ovary arcuate, 14-20 mm, densely puberulent. Sepals similar, narrowly lanceolate, 17-22 × ca. 4 mm, glabrous, 5-veined, apex acuminate. Petals linear, 17-22 × 2-3 mm, 3-veined, apex acuminate; lip adnate to entire length of column wings, white, tinged purple at apex, usually turning yellow later, 11-18 × 4-6 mm, 3-lobed or rarely almost unlobed; lateral lobes ovate-triangular or suboblong, oblique, ca. 7 mm across their apices, apical margin sometimes toothed, apex acute; mid-lobe elliptic-rhombic, 8-10 × 6-7 mm, base usually clawed, margin undulate and irregularly toothed, apex aristate; disk with 3-5 ridges; spur cylindric, slender, ca. 5 mm, glabrous or sparsely puberulent, apex obtuse. Column 4-5 mm, thick, dilated toward apex, glabrous or sometimes sparsely puberulent; column wings triangular, dilated at apex and embracing stigma; rostellum furcately 2-lobed; lobes ca. 1.2 mm; anther relatively small; pollinia narrowly ovoid, equal in size, ca. 1.2 mm; viscidium suboblong, small. Capsule subellipsoid, ca. 20 × 8 mm. Fl. May-Sep. 2n = 38*, 40*.
● Forests, soil-covered rocks along valleys; 1400-3100 m. S Gansu, Guizhou, W Hubei, Hunan, S Shaanxi, W Sichuan, Taiwan, NW and W Yunnan.