Benth.
Description
Megacarpaea polyandra Benth. is a robust alpine crucifer of the western and central Himalaya, known from about 99 records in India, Nepal and Pakistan, with scattered extralimital reports. It grows on open grassy and rocky alpine slopes, in subalpine scrub, forest clearings and along the margins of high pastures, generally between about 3000 and 4300 m. The plant photographed at Kalmura in West Nepal at 4100 m in June is typical of its preference for deep, moist, fertile soils on sunny slopes where it can attain a conspicuously large stature for an alpine herb.
The species is a stout perennial herb arising from a thick rootstock, with an erect, branching stem and large, deeply pinnatisect to lyrate leaves with several pairs of toothed lobes. The inflorescence is a broad panicle of many flowers; uniquely among most Brassicaceae the flowers bear numerous stamens (well in excess of the usual six), giving rise to the epithet "polyandra," and the petals are pale yellow to whitish. The fruit is the diagnostic feature: a large, flattened, didymous (two-lobed) silicle with broadly winged, papery valves, each loculus one-seeded, the whole readily wind-dispersed.
Megacarpaea is a small genus of central and high Asia notable for its polyandrous flowers and large winged fruits, features that set it apart within the mustard family and have made it of interest in studies of floral evolution in Brassicaceae. The young shoots and leaves are gathered locally as a potherb in parts of the Himalaya. Although widespread, its showy habit and use as a wild vegetable expose it to collection pressure, and as a narrow-belt alpine endemic it merits monitoring.
Author: Benth. · Sources: POWO (Kew), GBIF, Flora of Pakistan, Flora of Nepal, Hooker's Flora of British India, revision of Megacarpaea and tribe Megacarpaeeae