Ngamr.
Description
Roscoea bhutanica is a Himalayan terrestrial ginger known chiefly from Bhutan and adjacent southern China, with around 48 GBIF occurrences documenting its restricted Sino-Himalayan range. Unlike most Zingiberaceae, the genus Roscoea is adapted to cool temperate climates, and this species grows in open grassy slopes, forest clearings, banks and meadows in the upper temperate zone, broadly between 2,500 and 3,400 m. The plants photographed in the Haa Valley at 2,750 m and above Thimphu at 3,000 m, both in June, capture it flowering at the onset of the summer monsoon, when the rootstock breaks dormancy with the first rains.
It is a deciduous perennial herb arising from a cluster of fleshy, fasciculate roots and a short rhizome, producing an erect pseudostem formed by overlapping leaf sheaths. The leaves are few, lanceolate to oblong-lanceolate and glabrous, the lowermost reduced to bladeless sheaths. The inflorescence is terminal, the flowers emerging successively; each has a long, slender corolla tube, a hooded dorsal corolla lobe, two petaloid lateral staminodes, and a large, deflexed, bilobed labellum that is typically purple to violet, providing a conspicuous landing platform. The fruit is an elongate capsule containing numerous arillate seeds.
Roscoea comprises some twenty species disjunctly distributed across the Himalaya and the mountains of south-west China, a pattern interpreted as a response to Himalayan uplift and monsoon climate. R. bhutanica was segregated relatively recently from the R. tumjensis-R. alpina complex on floral and phenological characters, and its long, narrow corolla tube indicates pollination by long-tongued insects. Its limited range and dependence on undisturbed montane grassland make it of conservation interest given grazing and land-use change in the eastern Himalaya; it has not yet been formally assessed for the IUCN Red List. (The family is given as printed in the source; the species belongs to Zingiberaceae.)
Author: Ngamr. · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, The Genus Roscoea (Jill Cowley, Kew monograph), Zingiberaceae of the Himalaya