Large trees to small trees. Buttresses present, or absent; tall, or short. Spines absent. Stilt roots absent. Bark gray; not peeling in strips. Slash red, brown. Vertical stripes in the inner bark or wood present. Odor absent. Exudate absent. Terminal buds not enclosed by leaves.
Complex hairs absent. Stinging hairs absent. Mature twig indumentum present, or absent; sparse.
Leaves spiral; 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; prominent, or not prominent, but visible. Smallest veins not prominent, but visible; net like, or ladder like. Intramarginal vein present, or 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, or leafy; not fringed; large, or small; not persistent, or persistent. Domatia present, or absent. Basal glands present, or absent. Hairs on mature leaf present, or absent; sparse.
Inflorescences present; terminal, or axillary; on an unbranched axis, or 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; somewhat asymmetric; with male or female parts not raised on a column. Hypanthium present. Disk present; the stamens outside 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; not stalked; entire. Stamens 10-20(-100) (many); filaments present; free of each other; free of the perianth; all equal in size; diplostemonous, or polystemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 2. Styles solitary. Stigmas 1 lobed; distinctive; head shaped. Fruit drupaceous; non-fleshy; not multiple; not splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 1 per fruit; less than 5 mm, or about 1 cm long; wingless; with folds like marble, in cross- section; aril absent; non-endospermic.
Slash laminated; leaves glabrous; stipules leathery and subpersistent; stamens on one side of the flower; ovary at mouth of calyx tube. Taxon images: atuna.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.