Lindl.
Description
Calanthe chloroleuca is a terrestrial orchid of restricted distribution in the eastern Himalayas, known from Nepal, northeast India (Sikkim), Bhutan, and southwest China (Yunnan). With fewer than 20 documented occurrences in GBIF, it is one of the rarer Calanthe species in the region. The species grows in moist, shaded forest understory, on humus-rich soils among leaf litter, at elevations of 2,000–3,000 m.
The plant is an evergreen species with reduced pseudobulbs hidden by leaf bases. It produces 3–5 elliptic, plicate leaves 15–25 cm long. The inflorescence is an erect raceme 20–40 cm tall, carrying 8–15 flowers. The name 'chloroleuca' derives from Greek chloros (green) and leukos (white), accurately describing the flower coloration: sepals and petals are greenish-white, and the lip is white with a greenish or yellowish tinge, trilobed, with low, parallel keels on the disc. The spur is slender, 1–1.5 cm long, slightly curved. Flowering occurs from April to May.
Calanthe chloroleuca is easily confused with the similarly coloured C. brevicornu, from which it differs in its longer spur, narrower lip lobes, and more elongated floral bracts. Its rarity in herbarium collections may partly reflect the difficulty of distinguishing it from congeners in the field.
Author: Lindl. · Sources: POWO (Kew), Flora of Nepal Checklist, GBIF, Flora of Bhutan Vol. 3