(Maxim.) Hand.-Mazz.
Description
Halerpestes tricuspis is a small, stoloniferous perennial of the Ranunculaceae, distributed across the high mountains of Central Asia and the Himalaya. GBIF records (377 occurrences) document its presence in China, Nepal, India, Bhutan, Mongolia and Pakistan, where it occupies the alpine and subalpine zone. It is a characteristic plant of moist, often saline or marshy ground, the margins of glacial lakes, seepage flushes and streamsides, typically between 3,000 and 5,000 m. The photographed material from Dzongri in Sikkim at around 4,000 m in May exemplifies this preference for wet alpine meadows where snowmelt sustains permanently damp substrates.
The plant forms low mats by means of slender, rooting stolons. The leaves are basal, long-petiolate, with a small, fleshy, broadly cuneate to obovate blade that is characteristically three-toothed or shallowly three-lobed at the apex, the feature from which the epithet tricuspis derives. Flowering scapes are leafless and rise just above the foliage, each bearing one to few small, bright yellow flowers. The flowers have five sepals and five glossy petals each with a basal nectary scale; the numerous stamens surround a domed receptacle that develops into a globose to ovoid head of small, compressed, finely ridged achenes.
Formerly placed in Ranunculus, the genus Halerpestes is distinguished by its stoloniferous habit, the toothed leaf apices and the longitudinally ribbed achenes adapted to wetland dispersal. The species is an indicator of intact alpine wetland and flush communities, habitats sensitive to grazing pressure, trampling and hydrological change driven by glacial retreat. Though not currently of conservation concern owing to its wide range, its dependence on specialised wet microhabitats makes local populations vulnerable.
Author: (Maxim.) Hand.-Mazz. · Sources: POWO (Kew), Flora of China Vol. 6, Flora of Bhutan Vol. 1, GBIF, Tamura: Die natürlichen Pflanzenfamilien – Ranunculaceae (1995)