O.E.Schulz
Description
Draba oariocarpa is a high-alpine crucifer of the eastern Himalaya, known principally from Bhutan and adjoining areas, where GBIF holds only a single occurrence record, reflecting both its narrow distribution and its remote habitat. It is a plant of open alpine screes, stony slopes, moraines and frost-disturbed gravels of the upper alpine and subnival zones, generally above 4000 m. The photograph from the Thitha Tso in Bhutan at about 4360 m in July shows the species flowering in the brief high-summer window in its harsh, exposed lakeside scree habitat.
The plant is a small, tufted or cushion-forming perennial arising from a branched caudex topped by rosettes of leaves. The leaves are small, oblong to spathulate, entire or nearly so, and clothed in the stellate and simple hairs characteristic of the genus, giving a greyish, roughened texture. From the rosettes arise short, leafless or few-leaved scapes bearing a compact raceme of small flowers; these have four sepals and four yellow (sometimes fading whitish) petals in the cruciform arrangement typical of the Brassicaceae, with six stamens. The fruit, alluded to in the epithet oariocarpa (egg-fruited), is a small, ovate to elliptic, somewhat flattened silicula containing several seeds.
Draba is a very large, predominantly arctic-alpine genus of the Brassicaceae, taxonomically intricate owing to widespread polyploidy, apomixis and minor morphological differentiation, so that many narrowly defined species and synonyms have been described from the Himalaya and Tibet. The dwarf cushion habit and dense indumentum are classic adaptations to the cold, desiccating and intensely irradiated subnival environment. Given its apparently very restricted range and few documented collections, D. oariocarpa is poorly known and warrants further field assessment of its distribution and status.
Author: O.E.Schulz · Sources: POWO (Kew), GBIF, Flora of Bhutan, Flora of China, Annotated Checklist of the Flowering Plants of Nepal, Al-Shehbaz's systematic studies of Draba and the Brassicaceae