Family: Fabaceae |
Trees or shrubs, sometimes sprawling or climbing, often with prickles or stipular spines. Leaves bipinnately compound or modified into phyllodes of petiolar origin (in A. koa both types together in saplings), often with extrafloral glands on leaf rachises. Flowers mimosaceous, often mixed with sterile, clavate flowers, perfect or both staminate and perfect, in spikes or heads, these often arranged in racemes or panicles, bracteoles absent; calyx campanulate, truncate or obscurely 4-5-toothed; corolla 4-5(-7)-lobed, the lobes shorter than the tube; stamens 30 to more than 200, distinct; anthers ± with a gland. Pods very variable, flat to compressed, rarely cylindrical, ovate to linear, straight, curved, coiled, or contorted, sometimes moniliform, dehiscent or indehiscent. Seeds several, subglobose, lenticular, or ellipsoid, faces with a horseshoe-shaped pleurogram. [Bentham, 1842; Cambage, 1924; Degener & Degener, 1983; Gray, 1854a; Hochreutiner, 1925; Pedley, 1975, 1986; Rock, 1919b; St. John, 1979f; Vassal, 1969; Whitesell, 1964] A genus of about 1,200 species, widespread but with a large number in Australia. Acacia is divided into 3 subgenera (Vassal, 1981): Acacia, plants with stipular spines and leaves bipinnately compound (A. farnesiana); Aciileiferum Vassal, plants without stipular spines but sometimes with prickles and leaves bipinnately compound (A. mearnsii, A. parramattensis); and Heterophyllum, plants without prickles, rarely with stipular spines or branches spinescent, and leaves bipinnately compound or reduced to phyllodes of petiolar origin (A. confusa, A. koa). Name derived from akakia, the Greek name for Acacia arabica (Lam.) Willd. [= A. nilotica (L.) Delile subsp. tomentosa (Benth.) Brenan], ultimately derived from akisy Greek word meaning a sharp point, in reference to the thorns of the plant. Acacia melanoxylon R. Br. ex Aiton, with phyllodes 7-13 cm long, 0.7-2 cm wide, flower heads in racemes, and pods coiled and 3-7 mm wide, has been planted by State for¬esters at least on Kaua‘i, 0‘ahu, Moloka‘i, and Maui. During the final stages of preparation of this manuscript it was learned that this species has definitely become naturalized at least on East Maui, and may become a pest. |