Calanthe clavata Lindl., Gen. & Sp. Orch. 251. 1833; Su, Quart. J. Expt. Forest. Natl. Taiwan Univ. 4(3): 86, pl. 2. 1990.
Plants 50-60 cm tall, with distinct rhizomes. Rhizome 6-7 mm thick. Pseudobulbs 2-3 cm apart, clavate, 2-3 cm long, 7-10 mm thick, 4-5 nodose, usually covered by leaf bases. Leaves 4-6, fascicled or nearly distichous from pseudobulb, oblanceolate or linear oblanceolate, 25-50 cm long, 3.5-6 cm wide, apex acuminate, base long decurrent into petiole. Scape arising from base of pseudobulb or axil of lowest leaf, 20-40 cm long, 4-5 mm in diam., with 3 or 4 tubular sheaths below; bracts caducous, linear-lan-ceolate, 15-20 mm long, 3-4 mm wide, acuminate; pedicel 5-7 mm long; ovary 7-8 mm long. Flowers 15-20, yellow; dorsal sepal oblong, 10-12 mm long, 4-5 mm wide, acute, lateral sepals similar to dorsal one but slightly larger and oblique, often apiculate at apex; petals obovate, 9-11 mm long, 5.5-6.5 mm wide, obtuse at apex, contracted at base; lip connate with column at base, 6-8 mm long, 5-6 mm wide, continuous to spur at base, 3-lobed, lateral lobes ovate-triangular, 2-3 mm long, obtuse, terminal lobe obovate or nearly orbicular in outline, 3-4 mm long, retuse or shallowly 2-lobed at apex, sinus usually apiculate, disc with 2 erect lamellae at base, spur clavate, 6-8 mm long, slightly curved forward; column ca. 5 mm long, connate entire length with base of lip; anther ovate-lanceolate, 1.8-2 mm long; pollinia clavate, 1.5 mm long, connected to an ellipsoid viscidium; stigma single, semiorbicular; rostellum erect, undivided, 1.5-2 mm long, acuminate at apex.
PINGTUNG: Linungshan, Su & Chen 8556, 8585.
Southern China, northeast India, the Himalaya, Indochina and Thailand. Taiwan, in moist forests at ca. 1,000 m in the northern part of Hengchun Peninsula.
The plants in Taiwan as described above have many characters intermediate between those of C. angustifolia and C. speciosa. The habitats of these three species are sympatric on the Hengchun Peninsula. These plants also have overlapping flowering periods. It is probable that C. clavata is a natural hybrid between C. angustifolia and C. speciosa. The name,C. clavata, is tentatively used here. Further study is desirable.