Acacias of Australia

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Acacia subsessilis A.R.Chapm. & Maslin




Occurs in disjunct localities from Mount Farmer HS to Yalgoo and Fields Find, W.A.


Shrub 1–2 m high, rounded or funnel-shaped, straggly. Branchlets with raised stem-projections where phyllodes have fallen, lenticellular, glabrous. Phyllodes sessile to subsessile, mostly narrowly linear, flat to ±terete, 1–3 cm long, 0.8–1.5 mm wide, pungent, rigid, glabrous, dull green or pale reddish; with 8 nerves in all, 3 nerves per face when phyllodes flat; gland to 0–2 mm above base. Inflorescences simple, 1 per axil; peduncles 2–6 mm long, glabrous or sparsely puberulous; heads obloid to short-cylindrical, 7–15 mm long, 4–6 mm diam., subdense. Flowers 5-merous; sepals united for 3/4–4/5 their length. Pods submoniliform, to 8 cm long, 5–6 mm wide, thinly coriaceous to thinly crustaceous, glabrous. Seeds (few seen) longitudinal, elliptic, 3.5–4 mm long, ±shiny, black; aril cream.


Grows in shallow red sand and stony gravel, often on rocky slopes in open shrubland.


W.A.: 4.2 km E of Yalgoo, R.J.Cumming 1978 (CANB, NSW, PERTH); Mount Farmer Stn, P.J.Curry 1052 (CANB, MEL, PERTH); between Ningham Stn and Fields Find, B.R.Maslin 4246 (CANB, PERTH).


Like its close relative, A. diallaga, an unusual feature of this species is that its phyllodes change colour (from green to pale reddish) when water becomes limiting during periods of drought. Unless the phyllodes die they revert to their normal green colour when conditions improve with the advent of rainfall.

One collection with flat phyllodes has been seen (P.J.Curry 1052) from the northernmost extent of the range.

Superficially resembles A. colletioides and A. chapmanii subsp. chapmanii but these two are readily distinguished by their globular to subglobular heads, consistently terete phyllodes and strongly curved to coiled pods.

FOA Reference

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


A.R.Chapman, B.R.Maslin