(Banks) Blume
Description
Phaius tankervilleae, the nun's-hood or swamp orchid, is a robust terrestrial orchid with an exceptionally wide Old World tropical and subtropical distribution, recorded from China, India, Bhutan, Indonesia, Malaysia, Papua New Guinea, Australia, the Pacific islands and many other regions, with around 660 occurrence records (some, as in the Americas and Caribbean, reflecting introduction). It grows in damp grassland, marsh margins, swampy forest clearings and moist roadside banks from the lowlands into the lower hills. The photographed plant from Samtengang in western Bhutan at 2040 m, flowering in April, lies toward the upper part of its montane range.
It is a large terrestrial orchid arising from clustered, conical pseudobulbs partly buried in the substrate. The leaves are few, large, broadly lanceolate, plicate (longitudinally pleated) and tapered to a sheathing base. The inflorescence is a tall, erect raceme bearing many showy flowers; the sepals and petals are similar, brownish-red to maroon within and silvery-white outside, while the prominent labellum is tubular and rolled, white flushed with rose-purple and yellow in the throat, with a short basal spur. The fruit is a pendulous capsule releasing innumerable dust-like seeds.
The accepted name Phaius tankervilleae, based on Banks's epithet and combined by Blume, is treated as current despite synonym status in the source dataset; the input family spelling "Orchideaceae" is a variant of the correct Orchidaceae. Like nearly all orchids it depends on mycorrhizal fungi for seed germination. Widely grown as an ornamental and broadly distributed in the wild, it is nonetheless locally threatened by wetland drainage and over-collection in parts of its range.
Author: (Banks) Blume · Sources: POWO (Kew), GBIF, Flora of China (Orchidaceae), Grierson & Long Flora of Bhutan, The Orchids of Bhutan (Pearce & Cribb), Seidenfaden's revisions of mainland Asian Orchidaceae