Croton

Family Euphorbiaceae. Order Euphorbiales.

Small trees to shrubs. Buttresses absent. Spines absent. Stilt roots absent. Bark gray; not peeling in strips. Exudate present, or absent; red; flowing, or spotty; not blackening on exposure to air. Terminal buds not enclosed by leaves.

Complex hairs present, or absent; disk-shaped, or star-like. Stinging hairs absent. Mature twig indumentum present, or absent; dense, or sparse.

Leaves spiral; not scale-like; simple; of different sorts on a single twig, or all of the same type; not modified into spines; coriaceous; gland-dotted, or not gland-dotted; symmetric at the base; not dissected; smooth margined, or wavy margined, or with small to large teeth on margin. Epidermis not waxy. Venation pinnate, or trinerved. Secondary veins open; prominent, or not prominent, but visible. Smallest veins not prominent, but visible; net like, or ladder like. Intramarginal vein absent. Stalk of blade less than a quarter the length of the blade to a quarter to one half the length of the blade; not winged; attached to surface of leaf blade, attached to base of leaf blade; not swollen, or swollen; swollen at one end. Stipules present; free from one another; laterally placed; not encircling the twig; scale-like; not fringed; small; not persistent. Domatia absent. Basal glands present, or absent. Hairs on mature leaf present, or absent; dense, or sparse.

Inflorescences present, or represented by solitary flowers only; terminal; 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; not 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. 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 (male), or absent (female); 5; free; not fleshy; deciduous; not stalked; entire. Stamens 100; filaments present; free of each other; free of the perianth; all equal in size; polystemonous. Anthers 2 loculed; attached by the base; not awned; dehiscing by long slits. Ovary superior. Carpels joined; 3. Locules 3. Styles solitary, or free; 3. Stigmas 6 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, or about 1 cm long; wingless; uniform in cross-section; aril absent; endospermic.

Two glands usually found at lamina base; large variation in leaf shape on a single shoot common; leaves often turn conspicuously red before falling. Taxon images: gencroto.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.