Acacias of Australia

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Acacia sessilispica Maiden & Blakely




Occurs from Ballidu SE to Ravensthorpe with one collection from near Higginsville (c. 200 km NE of Frank Hann Natl Park), south-western W.A.


Shrub 0.8-2.5 m high, spreading, rounded. Branchlets slightly angular, glabrous, sometimes resinous. Phyllodes ascending to erect, slightly incurved, terete to slightly compressed, 5-11.5 cm long, 1-1.3 mm diam., acuminate, coarsely pungent with straight to subuncinate tip, ±rigid, glabrous, with 8 closely parallel nerves separated by deep furrows as wide as or wider than nerve-width. Inflorescences simple; spikes sessile, often tapering towards apex when in bud, 10-28 mm long, 3-5 mm diam., densely flowered, pale golden to dark golden; receptacle glabrous; bracteoles peltate. Flowers 4-merous; sepals free or rarely joined basally. Pods deflexed, linear, strongly and sharply raised over but not usually constricted between seeds, straight, to 7 cm long, (2.5-) 3-4.5 mm wide, ±chartaceous, longitudinally ±wrinkled, glabrous. Seeds longitudinal, broadly elliptic to oblong-elliptic, depressed laterally, 3-4 mm long, smooth, glossy, black; aril apical, white.


Grows in granitic loam and sand, often near granite outcrops, mostly in shrubland and mallee communities.


W.A.: Wiacubbing Hill, 8 km due SE of Bencubbin, B.R.Maslin 1995 (AD, PERTH); 8 km from Hines Hill towards Nungarin, B.R.Maslin 2342 (CANB, K, PERTH); 14 km SE of Mt Gibbs, Frank Hann Natl Park, K.Newbey 6577 (CANB, K, MEL, PERTH); Wingarni Well, c. 40 km NNW of Norseman, K.Newbey 8573 (PERTH); Fitzgerald R. bridge on main road between Ravensthorpe and Jerramungup, M.D.Tindale 3832 (BRI, K, MEL, NSW, PERTH).


As discussed by R.S.Cowan & B.R.Maslin, Nuytsia 10: 45 (1995), A. sessilispica is closely related to A. multispicata which has phyllodes with 8-20 nerves that are not separated by deep furrows, spikes in bud that are not apically narrowed, puberulous receptacles, broadly fan-shaped bracteoles, at least half-connate sepals and pitted and/or verruculose seeds. Also related to A. jibberdingensis and superficially similar to A. synoria. The phyllodes of A. sessilispica have a superficial resemblance to those of A. ephedroides which is readily distinguished by its 5-merous flowers and densely hairy pods.

Some collections from the southern end of the distribution range have narrower pods (c. 2.5 mm wide) somewhat constricted between the seeds but otherwise are apparently this species (e.g. c. 41 km ENE of Lake King, K.Newbey 6577, PERTH).

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 B.R.Maslin & J.Reid