Tetractomia

Family Rutaceae. Order Sapindales.

Large trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark not peeling in strips. Vertical stripes in the inner bark or wood 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; leathery; 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 prominent, or not prominent, but visible; 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, or swollen; swollen at one end. 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 bisexual; 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. Perianth present; with distinct calyx and corolla whorls. Sepals 4; partially joined; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 4; free; not fleshy; persistent; not stalked; entire. Stamens 4; filaments present; free of each other; free of the perianth; all equal in size; isomerous. Anthers 2 loculed; attached along the side; not awned; dehiscing by long slits. Ovary superior. Carpels partially joined, by base, or partially joined, by styles; 4. Locules 1-4 (1 or 4). Styles solitary. Stigmas 1 lobed; distinctive; head shaped. Fruit follicular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; winged. Seeds 1-2 per fruit; less than 5 mm; winged; uniform in cross-section; aril absent; endospermic.

Leaves simple, opposite; 4 staminodes per flower. Taxon images: tetrac.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.