Acacia

Family Fabaceae. Order Fabales.

Large trees to shrubs, or climbers. Buttresses absent. Spines present, or absent; on branches. Stilt roots absent. Bark gray; not peeling in strips. Slash cream, yellow. 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 (phyllodes), or compound; pinnate, or bipinnate; without a terminal leaflet; leaflets opposite; all of the same type; not modified into spines; coriaceous, or leathery; not gland-dotted; very asymmetric at the base, or symmetric at the base; not dissected; smooth margined. Epidermis waxy, or not waxy. Venation pinnate. Secondary veins open; not prominent, but visible to not visible. Smallest veins not prominent, but visible, or not visible; net like. Intramarginal vein present, or absent. Stalk of blade absent to less than a quarter the length of the blade; winged, or not winged; 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, or spiny; not fringed; small; not persistent, or persistent. Domatia absent. Basal glands absent. Hairs on mature leaf present, or absent; dense, or sparse.

Inflorescences present; terminal, or axillary; the flowers from a single point on the stem, or on an unbranched axis, or on a branched axis; specialized inflorescence units present, or absent; specialized inflorescence units heads; numerous and persistent inflorescence bracts absent. Flowers bisexual, or at least some flowers unisexual; with male and female flowers on different plants; not stalked, or stalked; about 0.5 cm long or across; round; with male or female parts raised on a column, or not raised on a column; with the female parts of the flower raised on a stalk. Hypanthium absent. Disk present, or absent; the stamens outside the disk. Perianth present; with distinct calyx and corolla whorls. Sepals 5; partially joined; not persistent in fruit; not growing any further after flowering. Epicalyx absent. Petals present; 5; all joined; not fleshy; deciduous; not stalked; entire. Stamens 15-100 (many); filaments present; free of each other; free of the perianth; all equal in size; triplostemonous, or polystemonous. Anthers 2 loculed; attached along the side; not awned; dehiscing by short slits, or dehiscing by long slits. Ovary superior. Carpels solitary; 1. Locules 1. Styles solitary. Stigmas 1 lobed; not distinctive. Fruit legume-like; non-fleshy; not multiple; splitting, or not splitting; not enclosed in, or sitting on, fleshy perianth parts; wingless. Seeds 100 per fruit (many); less than 5 mm to much more than 1 cm long; wingless; uniform in cross-section; aril present, or aril absent; non-endospermic.

Thorny or non-thorny trees, shrubs or lianas; leaves bipinnate or the petioles modified into phyllodes; generally growing in open sunny places; stamens free. Taxon images: acacia.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.