Schltr.
Description
Habenaria dentata is a wide-ranging terrestrial orchid of tropical and subtropical Asia, documented in GBIF across 933 occurrences from China, Thailand, Japan, Taiwan, India, Vietnam, Myanmar, Nepal, Bhutan and beyond. It grows in grassy slopes, open forest, scrub and forest-margin clearings from the lowlands to about 2800 m. The photographed plant was found at Dochu-La in Bhutan at about 2800 m in September, at the upper edge of its range, flowering at the close of the monsoon when soil moisture remains high in the cool mid-montane zone.
It is a tuberous terrestrial herb arising from underground ellipsoid tubers, with an erect leafy stem 30-60 cm tall bearing several oblong-lanceolate to elliptic, clasping cauline leaves. The inflorescence is a dense terminal raceme of showy white flowers; the dorsal sepal and petals converge to form a hood, while the conspicuous three-lobed labellum has the lateral lobes broadly dilated and fringed-dentate along the margins, giving the epithet dentata, and bears a long, slender, downcurved spur. The column is short with the rostellum and pollinaria typical of Habenaria, and pollination is effected by long-tongued, often nocturnal moths attracted to the white, spurred flowers.
Habenaria (Orchidaceae, subtribe Orchidinae) is a large, cosmopolitan genus of terrestrial orchids best diversified in the tropics, and like all orchids it is listed on CITES Appendix II. Seed germination depends on symbiosis with mycorrhizal fungi. Despite its broad distribution and relative frequency, populations are reduced locally by grassland conversion and collection, but the species is not globally threatened.
Author: Schltr. · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, The Orchids of Bhutan, CITES Appendix II listing