(Jack) Phengklai
Description
Sterculia lanceolata var. coccinea is a tree of tropical and subtropical Asia, ranging from the Indian subcontinent (India, Nepal, Sri Lanka) through Myanmar, Thailand, Indochina (Vietnam, Laos, Cambodia) and southern China into Malesia (Malaysia, Indonesia, Singapore, Brunei, Philippines), as reflected in the 322 GBIF records. It occurs in evergreen and semi-evergreen lowland to lower-montane forest, along streams and forest margins, typically below about 1500 m. The photographed tree from Zhemgang in central Bhutan at around 950 m, fruiting in October, sits at the warm-temperate northern edge of the species' range, where the bright fruiting display is conspicuous in autumn.
The variety is a small to medium tree with a slender bole and spreading crown. The leaves are alternate, simple, elliptic-lanceolate to oblong, entire, glabrescent and pinnately veined, on slender petioles — the lanceolate blade distinguishing this species from the palmately lobed S. villosa. The small flowers are apetalous with a campanulate, lobed calyx and are borne in axillary panicles; the variety coccinea is named for its scarlet colouring. The fruit is the diagnostic cluster of woody, beaked follicles that ripen a vivid red ('coccineus') and split open to reveal glossy black seeds against the crimson inner wall.
Now classified in Malvaceae subfamily Sterculioideae (formerly Sterculiaceae), Sterculia lanceolata is a variable species, and this variety, based on the basionym described by Jack and recombined by Phengklai, segregates the scarlet-fruited Malesian-Indochinese populations. The boldly coloured dehisced follicles are bird-dispersed, the contrasting red and black serving as a visual lure. Widespread and occurring in both primary and secondary forest, the taxon is not regarded as threatened.
Author: (Jack) Phengklai · Sources: POWO (Kew), GBIF, Flora of Thailand, Flora of China, Flora of British India, Kostermans Sterculiaceae monograph