Acacias of Australia

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Acacia atopa Pedley




Restricted to a small area in the Gascoyne R. basin in the vicinity of Gascoyne Junction, W.A.


Tree to 4.5 m tall, slender, occasionally weeping. Branchlets slender, with white appressed hairs between brown resinous ribs. Phyllodes linear, terete, 6–12 cm long, 0.7–1 mm diam., striate with longitudinal resinous ribs, appressed-pubescent between them. Inflorescences single in axils; peduncles 4–8 (–10) mm long; spikes c. 20 mm long, rather loose. Flowers 5‑merous; calyx c. 0.7 mm long, with oblong lobes and a distinct tube 0.1–0.2 mm long, with a few hairs on lobes; corolla c. 1.2 mm long, with a few hairs on tips; stamens c. 2.5 mm long; ovary with dense appressed longish hairs. Pods linear, not stipitate, straight, square in transverse section, to 3.5 cm long, 2–4 mm wide, with narrow longitudinal wings 0.5 mm wide on angles, pale brown, upper and lower surfaces with coarse irregular longitudinal ribs and yellowish nerves between them, appressed-pubescent, dehiscent. Seeds longitudinal, narrowly oblong, to 8 mm long and 1.7 mm wide; aril not developed (absent?).


Recorded from red clay and red clay-loam, sometimes in rocky situations. ‘Mulga’, Acacia ramulosa, Eremophila spp. and Senna spp are reported to be associated woody species.


W.A.: Gascoyne R., Kennedy Ra., C.A.Gardner 6082 (PERTH); same locality, J.S.Beard 4489 (PERTH); Injinu Spring in Injinu Hills on Dalgety Downs Stn, G.Johnstone 1/84 (PERTH).


The narrow geographic range of this species overlaps the ranges of A. ramulosa var. linophylla and A. subtessarogona. It possibly originated as a result of hybridism between the two taxa. Its phyllodes resemble those of A. ramulosa and its pods are structurally similar to those of A. subtessarogona although much smaller.

FOA Reference

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



Minor edits by J.Reid & J.Rogers