Triomma

Triomma Hook. f.

Description:
Dioecious large trees, tall plank buttresses present; bark scaly or smooth. Pith of branchlets without vascular bundles. resin translucent, aromatic. Leaves evergreen, imparipinnate, exstipulate; pulvinulus present at apex of terminal petiolule; leaflets entire; several long parallel inter-secondary veins present on each leaflet, freely ending veinlets highly branched. Inflorescences (pseudo-)terminal.  Perianth (4)5-parted, densely brown-pubescent; calyx divided to near base; petals distinct, corolla induplicate-valvate, with inflexed apiculum; disk extrastaminal, of 5 discrete lobes; stamens 5, antesepalous, inserted inside base of disk lobes, filaments sometimes twisted so anther dehiscence appearing extrorse; pollen endoaperture circular, exine spinulose, tectate, apocolpial endexine present; pistillode greatly reduced and parenchymatous; ovary 3-locular, triangular; style short and thick, stigma capitate and 3-lobed.  Fruit a pseudocapsule, obturbinate to pyriform in profile, 3-winged, the 3 woody valves dehiscing to release 3 pyrenes separated by a persistent columella, the pyrenes strongly compressed and broadly winged in plane perpendicular to radii of fruit axis, the wings rounded at base; seed located toward distal end of pyrene.  Cotyledons shallowly 5-lobed and folded or contortuplicate. Germination epigeal, phanerocotylar, first eophylls alternate, simple, margin serrate.

One sp., T. malaccensis Hook.f., on the Malay Peninsula, Borneo, and Sumatra, and Bihar in India.

Original Publication: Triomma Hook. f., Trans. Linn. Soc. 23: 171 (1860)

Bibliography: Leenhouts, Fl. Males. I, 5: 218–219 (1956).

Web Links:
Tropicos – Triomma

Images: