Stemonurus
Description
Trees, sometimes with buttresses or with pneumatophores, glabrous except a fine subglandular puberulence on the inflorescences, the petals excluded.
Branchlets and buds often vernicose.
Leaves spiral, entire, coriaceous to various degrees, dark green to yellowish green above, paler beneath, sometimes tubercled on the undersurface, midrib narrowly sunken above, bold beneath, nerves pinnate, looping;
Flowers bisexual, sessile, white to yellowish, fragrant.
Petals (4-)5, valvate in bud, connate at base only, oblong, apex inflexed, midrib or keel often raised on both faces, caducous.
Stamens (4-)5;
Seed 1;
Distribution
Annam present, Asia-Tropical, Ceylon present, Cochinchina present, Flores present, Lesser Sunda Is present, Palau Is present, Solomon present, near Paku, 900 m present
About 12 spp., 2 of which in Cochinchina and Annam, 1 in Ceylon; in Malesia 9 spp., one of which extends to the Solomon and Palau Is.Lesser Sunda Is. (Flores; near Paku, 900 m, Schmutz 3371, specimen in fr.; identified by Sleumer). .
Dispersal
The ripe fruits with their fibrous outer and hard inner endocarp are apparently able to float. This may explain the wide area of distribution of S. ammui (Palau Is., northcoast of New Guinea, New Britain, Solomon Is.) which occurs both in lowland hillside and in coastal swamp forest, even in the mangrove.
Notes
The genus comprises two groups of species, one with uni- or biseriately arranged flowers around S.secundiflorus Bl. (W. Malesia incl. Celebes), the other with flowers crowded at the end of the branches of the umbel around S. umbellata BECC. (W. to E. Malesia, Solomon and Palau Is.). Within these two groups the species must be distinguished mainly by calyx and fruit characters, as their leaf and other flower characters overlap to rather great extent.