Acacias of Australia

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Acacia diallaga Maslin & Buscumb




Restricted to discontinuous populations over c. 30 km on Karara Stn and Warriedar Stn, E of Morawa, W.A.


Dense, spreading, intricate shrub 0.5–1.5 (–3) m high. Branchlets obscurely ribbed, lenticellular, glabrous. Phyllodes narrowly elliptic to narrowly oblong-elliptic or lanceolate, slightly asymmetric, straight to shallowly recurved, ±patent, (11–) 15–36 mm long, (3–) 5–6 (–7) mm wide, pungent, rigid, glabrous, glaucous to subglaucous (green on new shoots) or red-purple; 3-nerved, minor nerves openly anastomosing; pulvinus much reduced. Inflorescences simple; peduncles 2–4 mm long, ±glabrous, basal bract often persistent; spikes 5–10 mm long, light golden. Flowers 5-merous; sepals united for ¾ their length. Pods narrowly oblong, not or slightly constricted between seeds, 2.5–5.5 cm long, 4–4.5 mm wide, thinly coriaceous, glabrous, light brown. Seeds longitudinal, oblong, 3–4 mm long, black; aril creamy white.


Grows in skeletal soils on slopes or crests of low rocky hills in open Acacia and Allocasuarina shrubland.


W.A. [precise locality withheld for conservation reasons]: Karara Stn, C.Godden GIND opp 29 (PERTH); near Mt Mulgine, B.R.Maslin 9126 (CANB, PERTH); Warriedar Stn, 24 Apr. 2007, Woodman Environmental Consulting (PERTH).


An unusual feature of this species is that its phyllodes change colour (from glaucous/sub-glaucous to purple-red) when water becomes limiting during periods of drought. Unless the phyllodes die they revert to their normal glaucous/sub-glaucous colour when conditions improve with the advent of rainfall.

Related to A. subsessilis, which differs most obviously in its narrower, symmetrical, dull green phyllodes that lack anastomosing minor nerves and its broader pods that are shallowly to moderately constricted between the smaller seeds. The two species grow close to one another but are not known to be sympatric.

FOA Reference

Flora of Australia Project


J.Reid, B.R.Maslin