Large trees to small trees. Buttresses present; tall, or short. Spines absent. Stilt roots absent. Bark gray, brown; not peeling in strips. Slash yellow. Vertical stripes in the inner bark or wood absent. Odor absent. Exudate absent. Terminal buds not enclosed by leaves.
Complex hairs present; star-like. 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; prominent. Smallest veins prominent; 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, or swollen; swollen at one end. Stipules present; free from one another; laterally placed; not encircling the twig; scale-like; not fringed; large; not persistent to persistent. Domatia absent. Basal glands absent. Hairs on mature leaf present; dense.
Inflorescences present; 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; 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; free; not fleshy; deciduous; not stalked; entire. Stamens 25-30(-100) (many); filaments present; free of each other; free of the perianth; of different sizes; polystemonous. Anthers 2 loculed; attached by the base; awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 3. Styles solitary. Stigmas 1 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 to much more than 1 cm long; wingless; uniform in cross-section; aril absent; endospermic.
No intramarginal vein; inflorescences cymose; leaf base heart-shaped; leaf covered in stellate hairs. Taxon images: upuna.gif upuna2.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.