Alstonia

Family Apocynaceae. Order Gentianales.

Emergent trees to small trees. Buttresses present, or absent; tall. Spines absent. Stilt roots present, or absent. Bark white, cream, brown, black; not peeling in strips. Slash cream, yellow. Vertical stripes in the inner bark or wood absent. Odor absent. Exudate present; white; flowing; not blackening on exposure to air. Terminal buds enclosed by leaves, or not enclosed by leaves.

Complex hairs absent. Stinging hairs absent. Mature twig indumentum absent.

Leaves whorled; 3-10 per whorl; 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, or closed; prominent, or not prominent, but visible. Smallest veins not prominent, but visible, or not 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 absent. Domatia absent. Basal glands absent. Hairs on mature leaf present, or absent; dense.

Inflorescences present; terminal; on an unbranched axis, or on a branched axis; specialized inflorescence units absent; numerous and persistent inflorescence bracts absent. Flowers bisexual; stalked; about 0.5 cm long or across, or to about 3 cm long o