Family

Fabaceae

Distribution

Occurs from Ravensthorpe WSW to the Fitzgerald R. (c. 30 km due E of Jerramungup), south-western W.A.

Description

Prostrate or semi-prostrate shrub to 0.5 m high and 2 m across. Branchlets slightly to prominently flexuose, glabrous. Stipules persistent. Phyllodes continuous with branchlets, bifariously decurrent and forming opposite wings with each one extending to the next below, 1–3.5 cm long, 4–10 mm wide, coriaceous, green to subglaucous, glabrous except axils densely and minutely resin-haired; margins occasionally undulate; free portion of phyllode with obviously rounded adaxial margin, 5–15 mm long, excentrically mucronate, with main nerve ±obscure or superficially absent; gland not prominent. Inflorescences rudimentary, 1-headed racemes with axes 0.5–1.5 mm long; peduncles 2–12 mm long, glabrous, sometimes descending in fruit; heads globular, 16–23-flowered, light golden. Flowers 5-merous; sepals ±free; petals nerveless. Pods strongly curved to twice-coiled, ±terete, to 2 cm long, 2–3 mm wide, thinly crustaceous, black, ±glabrous. Seeds longitudinal, oblong, c. 3 mm long; aril terminal, conical.

Habitat

Grows in clay, loam and sand, in scrub, mallee communities and woodland.

Specimens

W.A.: Fitzgerald R. crossing on Jerramungup–Ravensthorpe road, B.R.Maslin 802 (AD, CANB, K, MEL, MO, NSW, PERTH); c. 7 km from Ravensthorpe towards Lake King, B.R.Maslin 2577 (AD, B, BRI, MEL, PERTH).

Notes

Closely related to A. glaucoptera which is most readily distinguished by its glaucous phyllodes which have a dense tuft of white hairs in their axils (minutely resin-haired in A. bifaria) and heads 30–80-flowered; also, in A. glaucoptera the free portion of the phyllode is generally longer, broader and commonly with an acute or acuminate apex. Acacia bifaria has a more restricted distribution than A. glaucoptera and although both are common around Ravensthorpe it is not known if they are ever sympatric.

The phyllodes on some specimens from around Ravensthorpe are occasionally undulate as in the Bremer Bay variant of A. glaucoptera.

FOA Reference

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

Author

B.R.Maslin