Hook.f. & Thomson ex C.B.Clarke
Description
Helwingia himalaica is a Sino-Himalayan shrub distributed from China through Nepal, India, Bhutan and Myanmar to Vietnam, with over 1300 documented occurrences spanning the eastern Himalaya and southwest China. It grows in the understorey of evergreen and mixed broad-leaved forest, along shaded ravines and moist montane slopes, typically between roughly 1300 and 2700 m. The photographed plant from Chainribas in West Bengal, India at 1660 m, flowering in May, is characteristic of its occurrence in humid, shaded subtropical to lower temperate forest in the eastern Himalaya, where it forms part of the shrub layer.
It is a dioecious, evergreen to semi-evergreen shrub with slender, glabrous branches. The leaves are alternate, lanceolate to narrowly elliptic or oblong, with a setulose-serrulate margin, an acuminate apex and a cuneate base, and small filiform stipule-like appendages at the petiole base. The most remarkable feature is the epiphyllous inflorescence: the small, greenish, four- to five-merous unisexual flowers are borne in clusters on the upper surface (adaxial midrib) of the leaf, a phenomenon resulting from the adnation of the floral axis to the petiole and midrib. Staminate flowers occur in small umbels and pistillate flowers singly or few together, the latter with an inferior ovary that ripens into a small, fleshy, black or red drupe.
Helwingia is the sole genus of the small family Helwingiaceae in the order Aquifoliales, distinguished from related families chiefly by its unique epiphyllous flowering. The greenish flowers are insect-pollinated, and the berry-like drupes are dispersed by birds. As a widespread and locally common forest understorey shrub across the Sino-Himalayan region, H. himalaica (the accepted name) is not considered threatened.
Author: Hook.f. & Thomson ex C.B.Clarke · Sources: POWO (Kew), GBIF, Flora of China Vol. 14, Flora of Bhutan Vol. 2, Flora of Nepal, Soltis et al. Aquifoliales phylogenetic studies (monograph)