Common Name

Southern Rock Wattle

Family

Fabaceae

Distribution

Occurs from Coolgardie E to Karonie (c. 100 km E of Kalgoorlie) and S to the vicinity of Norseman, W.A.

Description

Spreading shrub or tree 2.5–6 m tall. Bark dark grey, fibrous, longitudinally fissured. Branchlet ribs sometimes overlain by resin, glabrous or appressed-hairy at extremities. Phyllodes narrowly elliptic, acute to acuminate, 5–8.5 cm long, 4–7 mm wide, l:w = 8–21, falcately recurved, wide-spreading, finely multi-striate with central nerve slightly more pronounced than others, marginal nerve brown to red-brown and overlain by a ±thin to thick layer of light grey, opaque resin; gland basal. Inflorescences simple or rudimentary racemes to c. 1 mm long; peduncles (1–) 2–6 mm long, densely ±appressed puberulous when in flower; spikes obloid to short-cylindrical, 5–9 (–12) mm long, golden. Flowers 5 merous; sepals ±free. Pods linear to narrowly oblong, 4–8 cm long, 4–6 mm wide, ±thinly coriaceous-crustaceous, ±straight-edged, dark brown to dark red-brown (due to dense layer of glandular trichomes within a resin matrix), marginal nerve not or scarcely raised above face of valve. Seeds longitudinal in pods, mostly obloid, (3–) 4–6 mm long, with heart-shaped differentiated tissue at centre, aril creamy white.

Phenology

Flowers Apr. –Aug.; mature pods Nov.–Dec.

Habitat

Grows in shallow sandy clay-loam on rocky hills, commonly in Open Tall Shrubland or Open Low Woodland comprising scattered eucalypts, e.g. Eucalyptus griffithsii, E. longicornis.

Notes

A variant from Banded Ironstone Formation ranges about 150–200 km NE of Coolgardie probably belongs to this species, see B.R.Maslin, Nuytsia 24: 151 (2014) for discussion.

Related to A. quadrimarginea which has wider, ±woody pods with an obvious perpendicular marginal flange, larger seeds, commonly longer spikes and phyllodes that are often longer with a higher l: w ratio and which lack opaque resin on top of the marginal nerve.

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 and minor edits by P.G. Kodela