Large trees to shrubs. Buttresses present, or absent; tall. Spines absent. Stilt roots absent. Bark red, gray, brown; not peeling in strips. Slash yellow, red, brown. Vertical stripes in the inner bark or wood present, or absent. Odor absent. Exudate absent. Terminal buds not enclosed by leaves.
Complex hairs absent. Stinging hairs absent. Mature twig indumentum absent.
Leaves opposite; not scale-like; simple; all of the same type; not modified into spines; coriaceous, or leathery; not gland-dotted; symmetric at the base; dissected, or not dissected; palmately lobed; smooth margined. Epidermis waxy, or not waxy. Venation trinerved, or palmate. Secondary veins open; prominent, or not prominent, but visible. Smallest veins prominent, or not prominent, but visible; net like, or box like. Intramarginal vein present, or absent. Stalk of blade a quarter to one half the length of the blade to more than half the length of the blade; not winged; attached to base of leaf blade; not swollen, or swollen; swollen at one end. Stipules absent. Domatia present, or absent; appearing as hair tufts; scattered along midrib. Basal glands absent. Hairs on mature leaf absent.
Inflorescences present; terminal, or axillary; the flowers from a single point on the stem, or on a branched axis; specialized inflorescence units present, or absent; specialized inflorescence units corymbs; numerous and persistent inflorescence bracts present at the bottom of the inflorescence. Flowers at least some flowers unisexual; with male and female flowers on the same plant, or with male and female flowers on different plants; stalked; about 0.5 cm long or across; round; with male or female parts not raised on a column. Hypanthium absent. Disk present, or absent; the stamens inside the disk, or the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 4-5; free; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 4-5; free; not fleshy; deciduous; not stalked; entire. Stamens (4-)6(-10); filaments present; free of each other; free of the perianth; all equal in size; isomerous, or diplostemonous; opposite the sepals (when isomerous). Anthers 2 loculed; attached by the base; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 2. Locules 2. Styles solitary, or free; 2. Stigmas 1-2 lobed; not distinctive. Fruit a samara; non-fleshy; not multiple; splitting, or not splitting; not enclosed in, or sitting on, fleshy perianth parts; winged. Seeds 2 per fruit; less than 5 mm, or about 1 cm long; wingless; uniform in cross-section; aril absent; non-endospermic.
Leaves opposite and long petioled, trinerved at base; monoecious or dioecious; styles two; disk hairy in male flowers; fruit a samara. Taxon images: acer.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.