Buch.-Ham. ex D.Don
Description
Osbeckia stellata Buch.-Ham. ex D.Don is a shrub of the melastome family ranging across the Himalaya and tropical Asia, recorded from China, India, Nepal, Bhutan, Myanmar, Thailand, Vietnam, Malaysia and Laos, with about 704 GBIF occurrences. It grows on open hillsides, forest margins, scrub, grassy banks and disturbed slopes in the subtropical and warm-temperate belt, generally between about 900 and 2000 m. It was recorded in Bhutan at Tserang at 1300 and 1600 m and at Zhemgang around 1000 m, flowering in September and October, when its conspicuous magenta blooms colour the autumn hill vegetation of the outer ranges.
It is an erect, branched shrub with quadrangular, often reddish stems bearing appressed, bristly stellate or strigose hairs. The leaves are opposite, ovate-lanceolate, entire, and conspicuously three- to five-nerved with the characteristic curved-convergent venation of Melastomataceae, both surfaces rough with stiff hairs. The flowers are large and showy, borne in terminal cymose clusters; the four broad obovate petals are rose-purple to magenta, surrounding eight stamens with distinctively geniculate, beaked anthers, set on an urceolate hypanthium clothed in branched, stellate-tipped bristles. The fruit is an urn-shaped capsule enclosed by the persistent bristly hypanthium, releasing numerous minute cochleate seeds.
Osbeckia is distinguished from the related Melastoma by its smaller seeds and capsular fruit, and O. stellata is among the most ornamental and widespread Himalayan species, sometimes grown for its vivid flowers. Its poricidal anthers are buzz-pollinated by bees, while the small seeds are dispersed from the dry capsules. Common in disturbed and secondary habitats, it readily colonises cleared ground and is of no conservation concern.
Author: Buch.-Ham. ex D.Don · Sources: POWO (Kew), GBIF, Flora of China, Flora of Bhutan, Flora of British India, Melastomataceae monograph (Hansen revision of Osbeckia)