Sebastiania

Family Euphorbiaceae. Order Euphorbiales.

Large trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark yellow, gray, brown; not peeling in strips. Slash green, orange. 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 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 waxy, or not waxy. Venation pinnate. Secondary veins open; prominent. Smallest veins prominent to not prominent, but visible; net like. Intramarginal vein present. 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; not fringed; small; not persistent. Domatia absent. Basal glands absent. Hairs on mature leaf absent.

Inflorescences present, or represented by solitary flowers only (female in S. borneensis); terminal, or axillary; the flowers from a single point on the stem, or on an unbranched 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; round; with male or female parts not raised on a column. Hypanthium absent. Disk absent. Perianth present; with all whorls looking like sepals. Sepals 5; free; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals absent. Stamens 3; filaments present; free of each other; free of the perianth; all equal in size; anisomerous. Anthers 2 loculed; attached by the base; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 3. Styles solitary. Stigmas 3 lobed; not distinctive. Fruit capsular; non-fleshy; not multiple; splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 3 per fruit; less than 5 mm; wingless; uniform in cross-section; aril absent; endospermic.

Taxon images: sebast.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.