Triomma

Family Burseraceae. Order Sapindales.

Emergent trees to large trees. Buttresses present; tall, or short. Spines absent. Stilt roots absent. Bark gray, brown; not peeling in strips. Slash red, brown. Vertical stripes in the inner bark or wood absent. Odor aromatic. 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; with a terminal leaflet; leaflets opposite; all of the same type; not modified into spines; coriaceous, or leathery; not gland-dotted; very asymmetric at the base; not dissected; smooth margined. Epidermis not waxy. Venation pinnate. Secondary veins open; prominent. Smallest veins prominent; net 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 absent. Basal glands absent. Hairs on mature leaf absent.

Inflorescences present; 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 different plants; stalked; with the parts barely visible to the eye, or 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; not stalked; entire. Stamens 5; filaments present; free of each other; joined to the perianth; all equal in size; isomerous; opposite the sepals (when isomerous). Anthers 2 loculed; attached along the side; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 3. Styles absent. Stigmas 3 lobed; distinctive, or not distinctive; disk-like. Fruit capsular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; winged. Seeds 3 per fruit; less than 5 mm, or about 1 cm long; winged; uniform in cross-section; aril absent; non-endospermic.

Leaflets strongly asymmetrical; leaflet stalks not swollen; flowers 5-merous; disk extrastaminal; ovary triangular; fruits 3-winged capsules; seeds winged. Taxon images: triomma.gif gentriom.gif


Cite this publication as: Jarvie, J.K. and Ermayanti (1996 onwards). `Tree Genera of Borneo - Descriptions and Illustrations' URL http://django.harvard.edu/users/jjarvie/Borneo.htm/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.