WATTLE

Acacias of Australia

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Acacia microcarpa F.Muell.

Common Name

Manna Wattle

Family

Fabaceae

Distribution

Occurs in SE Australia from the Eyre Peninsula near Wudinna, S.A., E to Mallee Cliffs Natl Park, N.S.W., and to Gunbower, Vic., with an isolated occurrence farther E in N.S.W. in the Goolgowi–West Wyalong area.

Description

Glabrous shrub to 2.5 m high. Branchlets somewhat angled at extremities. Stipules insignificant. Phyllodes normally oblanceolate, sometimes oblong-oblanceolate, elliptic or elliptic-oblanceolate, straight to shallowly incurved, (1.6–) 2–5.5 (–7) cm long, (3–) 4–10 (–19) mm wide with l:w = 4–10, obtuse but frequently obliquely so, often retuse, slightly thickened, smooth; midrib not prominent; lateral nerves absent or obscure; glands 2, with apical gland adjacent to mucro, and lower one near or below phyllode middle, 0.5 mm long and normally shallowly concave. Inflorescences rudimentary 1-headed racemes with axes c. 0.5 mm long, 2–5 per node; peduncles 4–10 (–12) mm long, drying yellow or blackish; heads globular, 14–25-flowered, bright mid-golden. Flowers 5-merous; sepals free. Pods linear, prominently raised over seeds, slightly to prominently curved, to 8 cm long, 2–5 mm wide, firmly chartaceous. Seeds longitudinal, elliptic to widely elliptic-oblong, 3–4 mm long, subnitid, dark brown; aril ±clavate, 1/4–1/3 length of seed.

Habitat

Found in a variety of vegetation formations and soil types.

Specimens

S.A.: Wudinna, R.H.Kuchel 3302 (AD, PERTH); between Cambrai and Sedan, D.J.E.Whibley 4474 (AD). N.S.W.: 5 km NE of Goolgowi, G.M.Cunningham 3347 & P.L.Milthorpe (NSW, PERTH). Vic.: Big Desert, 21 km N of Broken Bucket bore, M.G.Corrick 6344 (MEL, PERTH); Gunbower, Oct. 1913, Anon. s.n. (MEL1500691).

Notes

Acacia halliana was formerly included within this species, fide B.R.Maslin, Nuytsia 6: 35–46 (1987). Bentham’s description in Fl. Austral. 2: 357 (1864) contains elements of both species as does the Mueller illustration which is cited above.

Similar to A. praemorsa which has much narrower phyllodes. Short phyllode forms (i.e. c. 2 cm long) may resemble A. triquetra which has branchlets more obviously angled, phyllodes usually with only an apical gland and straight to shallowly curved pods. Short phyllode forms may also resemble A. acinacea.

Acacia microcarpa together with A. acinacea, A. imbricata, A. praemorsa and A. triquetra comprise the ‘A. microcarpa group’; see B.R.Maslin, Nuytsia 6: 39 (1987) and P.Lang & B.R.Maslin, J. Adelaide Bot. Gard. 13: 118 (1990). Putative hybrids between A. microcarpa and A. triquetra occur on the Eyre Peninsula.

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia

Author

Minor edits by B.R.Maslin & J.Rogers

B.R.Maslin