Colona thorelii is a species small tree, in the family Malvaceae and now placed in the subfamily Grewioideae; it is named after the French botanist Clovis Thorel. No subspecies are listed in the Catalogue of Life.
The species is distributed in southern China (S. & SE. Yunnan), Indo-China (including Vietnam) and Peninsula Malaysia.
Trees grow to 5âÂÂ15 m tall, in forested areas up to 800m. The branches are grey-brown stellate and tomentose. Leaves have a petiole 5âÂÂ10 mm; leaf blades are oblong, 80-150 à40âÂÂ70 mm, thinly leathery, densely grey stellate tomentose abaxially, adaxially glabrous, smooth or slightly rough. There are five basal veins and 2-3 pairs of lateral veins; the leaf-base is rounded, margins are plain or slightly serrated near the (acute or acuminate) apex.
Flowering occurs in SeptemberâÂÂOctober in southern China with 40âÂÂ90 mm inflorescences which are terminal or axillary at twig tips. Flower petals are 5âÂÂ6 mm, with stamens as long as the petals. The bracts are triangular, ovate, or lanceolate, 5âÂÂ6 mm; bracteoles obovate; pedicel 3âÂÂ5 mm. Sepals are narrowly lanceolate, 6âÂÂ7 mm, abaxially grey hairy and adaxially glabrous. The ovary is 3-loculed, hairy; style ca. 5 mm; the stigma is 2-lobed. The grey seed capsules are 20âÂÂ25 mm in diameter, velvety and 3-winged, with wings approx. 10 mm wide.