Large trees to small trees. Buttresses present, or absent; tall, or short. Spines absent. Stilt roots absent. Bark white, cream, gray; not peeling in strips. Slash yellow, brown. Vertical stripes in the inner bark or wood absent. Odor absent. Exudate absent. Terminal buds not enclosed by leaves.
Complex hairs absent. Stinging hairs absent. Mature twig indumentum absent.
Leaves spiral; not scale-like; compound; pinnate; without a terminal leaflet; leaflets opposite, or leaflets alternate; all of the same type; not modified into spines; coriaceous; not gland-dotted; symmetric at the base; not dissected; smooth margined. Epidermis not waxy. Venation pinnate. Secondary veins open; prominent, or not prominent, but visible. Smallest veins prominent, or not prominent, but visible; net like, or box like. Intramarginal vein absent. Stalk of blade less than a quarter the length of the blade; not winged; attached to base of leaf blade; not swollen. Stipules absent. Domatia present; pit-like; scattered along midrib. Basal glands absent. Hairs on mature leaf absent.
Inflorescences present, or represented by solitary flowers only; axillary; on a branched axis; specialized inflorescence units absent; numerous and persistent inflorescence bracts absent. Flowers at least some flowers unisexual; with male and female flowers on the same plant; stalked; with the parts barely visible to the eye to about 0.5 cm long or across; round; with male or female parts not raised on a column. Hypanthium absent. Disk present; the stamens inside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 5; free; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 5; free; not fleshy; deciduous; stalked; entire. Stamens (7-)8(-9); filaments present; free of each other; free of the perianth; all equal in size; diplostemonous. Anthers 2 loculed; attached by the base; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 3. Styles solitary. Stigmas 3 lobed; not distinctive. Fruit capsular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 3 per fruit; about 1 cm long to much more than 1 cm long; wingless; uniform in cross-section; aril absent; non-endospermic.
Fruits 3-angled, apex sharp; no aril. Taxon images: trigonac.gif
Cite this publication as: Jarvie, J.K. and
Ermayanti (1996 onwards). `Tree Genera of Borneo – Descriptions and
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.