An evergreen small tree or shrub 15 to 30 ft high, of vigorous growth; young shoots angular, usually glabrous. Phyllodes leaf-like, leathery, oblong-lanceolate, blunt or more or less pointed, tapered at the base; 3 to 6 in. long, 3⁄8 to 3⁄4 in. wide; dark green. Flowers bright yellow, produced from the axils of the phyllodes in cylindrical spikes 11⁄2 to 2 in. long, 1⁄4 to 3⁄8 in. wide. Pod 3 to 4 in. long, 1⁄/6 to 1⁄3 in. wide. Bot. Mag., tt. 1827, 2166.
Native of the Australian mainland, and (if interpreted in a wide sense) of Tasmania; introduced in 1792 and ever since a popular cool greenhouse shrub. It can usually be recognised by its large, narrowly oblong 'leaves' and its long, rather slender flower-spikes, which open in spring. It has been grown in many Cornish gardens, and the late Sir F. Stern once had a plant against his house at Highdown, Worthing, eventually killed by frost. It is one of the most lime-tolerant species, and for that reason used on the French Riviera as a stock for other species. It is popular as a street tree in California.
var. sophorae (Labill.) F. v. Muell. Mimosa sophorae Labill. – Distinct in its spreading habit and short, broad phyllodes, often widest above the middle. It is found wild in Tasmania on sand dunes, and in S. and E. Australia; said to be very resistant to sea-winds. It is sometimes given specific rank as A. sophorae (Labill.) R. Br.
var. floribunda (Vent.) F. v. Muell. Mimosa floribunda Vent. – Phyllodes very narrow, 1⁄4 in. or less wide and 3 to 5 in. long, with prominent parallel veins.
A. mucronata Willd. – This is best considered as an independent species, although it is closely allied to A. longifolia, and has been considered a variety of it. It is widespread in Tasmania and is also found on the mainland in Victoria. Typically, this species has very narrow phyllodes, to about 1⁄5 in. wide at the most, with three to five rather prominent nerves; but in foliage characters it is very variable. Bot. Mag., t. 2747.
From the Supplement (Vol. V)
A. mucronata – This species is hardier than the related A. longifolia. Indeed, Messrs Hillier consider it to be the hardiest of the genus.