(Lindl. ex Wall.) Koord. & Valeton
Description
Engelhardia spicata var. colebrookeana is a subtropical tree of the walnut family ranging across the southern Himalaya and into Southeast Asia, with GBIF records from China, India, Nepal, Bhutan, Thailand, Vietnam, Indonesia and the Philippines. It is a component of warm broad-leaved and pine-oak forest, secondary woodland and forest margins, mostly between 800 and 2,000 m. The photographed tree grows at Tserang in southern Bhutan at about 1,660 m in September, when the long, drooping fruiting catkins with their winged nutlets are conspicuous in the subtropical foothill forest.
The plant is a medium-sized to large deciduous or semi-evergreen tree with grey, somewhat fissured bark. The leaves are alternate and pinnately compound, with several pairs of opposite to subopposite, elliptic-oblong, entire leaflets that are glabrous to finely hairy and oblique at the base. The species is monoecious, with slender pendulous catkins; the female flowers develop into a characteristic infructescence in which each small, hard nutlet is subtended by a large, three-lobed, membranous wing-bract that acts as a samara for wind dispersal. This trilobed wing readily distinguishes Engelhardia from its relatives in the family.
Following GBIF, this taxon is treated as a synonym under the accepted name Engelhardia spicata colebrookeana, a variety distinguished from typical E. spicata by indumentum and leaflet characters. The Juglandaceae are an economically and phylogenetically important temperate-to-tropical family, and Engelhardia represents its warm Asian element. The tree is widespread, used locally for timber, fuel and tannin, and is not considered threatened, persisting well in disturbed and secondary forest.
Author: (Lindl. ex Wall.) Koord. & Valeton · Sources: POWO (Kew), GBIF, Flora of China Vol. 4 (Juglandaceae), Grierson & Long: Flora of Bhutan Vol. 1, Manning: The Genera of Juglandaceae