Ailanthus

Family Simaroubaceae. Order Sapindales.

Large trees to small trees. Buttresses absent. Spines absent. Stilt roots absent. Bark green, brown; not peeling in strips. Slash yellow, brown. 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 present; dense, or sparse.

Leaves spiral; not scale-like; compound; pinnate; without a terminal leaflet, or with a terminal leaflet; leaflets opposite, or leaflets alternate; all of the same type; not modified into spines; coriaceous; not gland-dotted; very asymmetric at the base, or symmetric at the base; not dissected; smooth margined, or with small to large teeth on margin. Epidermis not waxy. Venation pinnate. Secondary veins open; prominent, or not prominent, but visible. Smallest veins not prominent, but visible, or not visible; net like. Intramarginal vein present, or 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 present, or absent; pit-like; scattered along midrib, or scattered across lamina. Basal glands present, or absent. Hairs on mature leaf present; dense.

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 the same plant, or with male and female flowers on different plants; stalked; about 0.5 cm long or across, or to about 3 cm long or across; round; with male or female parts not raised on a column. Hypanthium absent. Disk present; the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 2, or 5-6; free; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 5-6; free; not fleshy; deciduous; not stalked; entire. Stamens 10; filaments present; free of each other; free of the perianth; all equal in size; diplostemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by short slits, or dehiscing by long slits. Ovary superior. Carpels separate; 2-5. Locules 1. Styles free. Stigmas 1 lobed; not distinctive. Fruit a samara; non-fleshy; not multiple; not splitting; not enclosed in, or sitting on, fleshy perianth parts; winged, or wingless. Seeds 1 per fruit; less than 5 mm; winged; uniform in cross-section; aril absent; non-endospermic.

Taxon images: genailan.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.