Large trees to small trees. Buttresses present, or absent; tall, or short. Spines absent. Stilt roots present, or absent. Bark red, gray; not peeling in strips. Slash brown. Vertical stripes in the inner bark or wood absent. Odor resinous. Exudate absent. Terminal buds not enclosed by leaves.
Complex hairs absent. Stinging hairs absent. Mature twig indumentum present, or absent; dense, or sparse.
Leaves spiral, or two-ranked; not scale-like; simple; 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, or closed; prominent, or not prominent, but visible. Smallest veins not prominent, but visible, or not visible; net like, or ladder 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 present; free from one another; laterally placed; not encircling the twig; scale-like; not fringed; small; not persistent. Domatia present, or absent. Basal glands absent. Hairs on mature leaf present, or absent; dense, or sparse.
Inflorescences present; terminal, or axillary; on a branched axis; specialized inflorescence units absent; numerous and persistent inflorescence bracts absent. Flowers bisexual; stalked; about 0.5 cm long or across, or to about 3 cm long or across; round; with male or female parts not raised on a column. Hypanthium absent. Disk absent. Perianth present; with distinct calyx and corolla whorls. Sepals 5; free, or partially joined; persistent in fruit; with at least some sepals becoming wing-like; 2 becoming wing-like. Epicalyx absent. Petals present; 5; all joined; not fleshy; deciduous; not stalked; entire. Stamens 10-38(-100) (many); filaments present; free of each other; free of the perianth; all equal in size; diplostemonous, or triplostemonous, or polystemonous. Anthers 2 loculed; attached by the base; awned; dehiscing by long slits. Ovary superior, or partly inferior. Carpels joined; 3. Locules 3. Styles solitary. Stigmas 3 lobed; not distinctive. Fruit a nut; non-fleshy; not multiple; not splitting; not enclosed in, or sitting on, fleshy perianth parts; winged. Seeds 1 per fruit; about 1 cm long, or much more than 1 cm long; wingless; uniform in cross-section; aril absent; endospermic.
Large to medium trees; fruit usually with two wings; nut not adnate to calyx tube. Taxon images: genhopea.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.