WATTLE

Acacias of Australia

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Acacia semicircinalis Maiden & Blakely

Family

Fabaceae

Distribution

Restricted to the Wongan Hills, W.A.

Description

Diffuse shrub to 1 m high. Branches wiry and often prostrate (not dividing into short, divaricate branchlets), sometimes coarsely pungent, minutely verruculose at least at extremities, glabrous or hispidulous. Phyllodes oblong-elliptic to narrowly oblong-elliptic, sometimes lanceolate or ±circular, 1–2 cm long, 5–10 mm wide, l:w = 1.5–3, inequilateral at base, ±undulate, acute to obtuse and excentrically ±apiculate, sometimes coarsely pungent, sometimes subglaucous, glabrous or hirtellous with hairs often tubercle-based and confined to margins, 1-nerved per face; lateral nerves obscure. Inflorescences mostly simple and within axils of immature phyllodes at ends of branches; peduncles 5–13 mm long, glabrous or subglabrous; heads globular, c. 25-flowered, golden. Flowers normally 5-merous; sepals free, linear-spathulate. Pods narrowly oblong, shallowly arcuate, raised over but scarcely constricted between seeds, to 6 cm long, 4.5–6 mm wide, glabrous. Seeds longitudinal, oblong-elliptic, c. 6 mm long, arillate.

Habitat

Grows on hills in lateritic, often gravelly, soil on hills in mallee and Acacia shrubland.

Specimens

W.A.: NW of Wongan Hills [township] towards Piawaning, R.Coveny 7841 & B.R.Maslin (K, CANB, NSW, PERTH).

Notes

Sympatric with, and often confused with a related species, A. botrydion, which is a harsher, intricately branched shrub to 1.3 m high with terminal clusters of racemes or panicles that appear much later in the year and coiled pods (see B.R.Maslin, Nuytsia 4: 32 (1982), for discussion). Also sometimes confused with A. aculeiformis.

Conservation

Gazetted a rare species in W.A.

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

Minor edits by J.Rogers