Acacias of Australia

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Acacia pycnostachya F.Muell. ex Benth.

Common Name

Bolivia Wattle




Occurs on the Northern Tablelands, N.S.W., on the Bolivia Ra., from Bluff Rock to Bolivia Hill. There is a specimen collected from Laidley, Moreton District, Qld, J.King (NSW50214), but according to L.Pedley, Proc. Roy. Soc. Queensland 75: 59 (1964) this is probably labelled incorrectly.


Shrub or tree to 7 m high, pruinose. Bark scaly or slightly corrugated, dark brown over reddish. Branchlets flattened, coarse, 3.5–11 mm wide, purplish, orange-brown or tan, pruinose, sharply angled below phyllodes; ridge decurrent into narrow wing joining abaxial phyllode margin. Phyllodes oblique, elliptic to narrowly elliptic or sometimes slightly obovate or oblong-elliptic, 6–11.5 cm long, 10–30 mm wide, coriaceous, rigid, glabrous, with 3 nerves slightly more prominent; minor nerves mostly 3–4 per mm, longitudinal, conspicuous, rarely anastomosing; lower margin normally continuous with branchlet; gland minute, basal. Inflorescence racemose; raceme axis 1–9 (–15) mm long. Spikes subsessile, 2.5–7.5 cm long, dense, dark yellow. Flowers 5-merous (rarely 4-merous or with reduced fifth sepal amongst predominantly 5-merous flowers); calyx 0.8–1.1 mm long, sinuate, dissected to 1/5, pubescent especially margins and base, with fimbriolate margins; corolla 2.5–3 mm long, dissected to 1/3, with papillose apices; ovary villous. Pods linear, slightly constricted between and slightly raised over seeds, 8–12 cm long, 3–4 mm wide, longitudinally wrinkled; margins paler. Seeds longitudinal, oblong-elliptic, 4–6 mm long, black; pleurogram inconspicuous.


Flowers Aug.–Oct.


Grows amongst boulders on granite slopes in sandy soil, in dry heath and Eucalyptus -Callitris woodland.


N.S.W.: Shiny Ra., Bolivia, E.F.Constable 7084 (NSW, PERTH); 34.2 km S of Tenterfield, N.Hall H84/51 (NSW); Bolivia Mtn, L.Murray 67, R.G.Coveny & W.Bishop (AD, BRI, CANB, MEL, NSW, NY, PERTH, UC); Bluff Rock, 8 miles [12.8 km] S of Tenterfield, H.Salasoo 5470 (NSW).


Characterised by very coarse, sharply ridged but flattened branchlets.

FOA Reference

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


Dr M.D.Tindale and Dr P.G.Kodela with the assistance of M.Bedward, S.J.Davies, C.Herscovitch, D.A.Keith and/or D.A.Morrison

Minor edits by B.R.Maslin & J.Rogers