WATTLE

Acacias of Australia

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Acacia exudans Lindl.

Common Name

Casterton Wattle

Family

Fabaceae

Distribution

Endemic in south-western Vic. in a small area bounded approximately by the towns of Casterton, Hamilton and Dartmoor.

Description

Slightly aromatic, dense rounded shrub 1–4 m tall. Branchlets not or scarcely flexuose, ±angled at extremities but soon terete, glabrous, often thickly resinous between broad, ±flat-topped rib-like bands of yellow tissue. Stipules normally persistent, brittle therefore sometimes absent, (1–) 2–4 mm long. Phyllodes on persistent, raised stem projections, normally narrowly oblongelliptic to narrowly elliptic or oblanceolate, elliptic when phyllodes very broad, (25–) 30–60 (–70) mm long, (5–) 6–17 (–20) mm wide, somewhat shiny, scattered resinous-punctate, normally glabrous, 2-nerved per face, lateral nerves few and obscure; apices acute or obtuse, mucronate (mucro ±central); gland 0–3 (–4) mm above pulvinus. Inflorescences simple, 1 or 2 (3) per axil; peduncles (4–) 5–10 mm long, ±stout, densely tomentose with short, crisped, spreading hairs; basal peduncular bract early caducous or persistent to anthesis, cucullate-rostriform, large (3–4 x 2–3 mm); heads globose, large (6–9 mm wide dry), densely 50–60-flowered; bracteoles exserted in young buds, acute to short-acuminate. Flowers 5-merous; sepals united almost to their apices. Pods narrowly oblong, 20–70 mm long, 5–7 (–8) mm wide, thinly coriaceous-crustaceous, glabrous. Seeds longitudinal, oblong to circular, 3.8–4.3 mm long, dark brown to black; arillate.

Phenology

Flowers Sept. –Oct.; fruits Dec. –Feb./Mar.

Habitat

Grows in low undulating country in heath or low eucalypt woodland in areas that have been extensively cleared for agriculture; most remaining plants are found along degraded road verges.

Specimens

Vic.: East Greenwald Rd 2.2 km from Princes Highway, D.J.Murphy 72 and N.Middleton (MEL, PERTH); about 5 km E of Casterton–Dartmoor main road, along Moonlight Rd (c. 22 km SSW of Casterton), P.S.Short 1316 (BRI, MEL); Winnap, I.B.Wilson 774 (CANB).

Notes

Referred to as the third variant of A. verniciflua by B.R.Maslin, Fl. Australia 11A: 597 (2001). Most closely related to the allopatric, geographically restricted Vic. endemic, A. rostriformis, which is most readily distinguished by its appressed-hairy branchlets, rostriform phyllodes with an excentric mucro, caducous stipules and fewer-flowered heads. Also related to A. verniciflua which has caducous stipules, smaller, caducous basal peduncular bracts and glabrous or sparsely appressed hairy peduncles. Acacia exudans may sometimes resemble A. leprosa var. crassipoda. A hybrid between a cultivated plant of A. howittii and a naturally occurring plant of A. exudans occurs near Casterton, fide B.R.Maslin & D.Murphy, Muelleria 27: 194 (2009).

FOA Reference

Flora of Australia Project

Author

B.R.Maslin