An evergreen shrub 10 ft or more high, of densely bushy shape; young shoots ribbed and usually more or less (sometimes very) bristly. 'Leaves' (phyllodes) in the form generally cultivated closely set on the twigs, obliquely oblong or linear-oblong with a curved point; 1⁄2 to 1 in. long, 1⁄8 to 1⁄4 in. wide; glabrous, dark green. Each joint of the twigs in the typical form is armed with a forked pair of needlelike spines 1⁄/6 to 1⁄2 in. long which are really modified stipules, but these are often absent in cultivated forms. Flowers rich yellow, produced in balls 1⁄3 in. wide singly or in pairs, each ball on a slender stalk 1⁄3 to 3⁄4 in. long. Pod 11⁄2 to 2 in. long, 1⁄/6 to 1⁄4 in. wide, softly silky. Bot. Mag., t. 1653.
Native of Australia where it is widespread, although absent from Tasmania; introduced in 1803. It is the best known and commonest of pot-grown or greenhouse acacias, requiring little winter heat and always flowering well in spring. It is cultivated out-of-doors, happiest against a wall, in various Cornish gardens. There are quite a number of forms in cultivation, varying chiefly in the size and shape of the phyllodes.
A. acinacea Lindl. – A closely allied species, differing mainly in its non-spiny stipules.