Acacia disticha Maslin
Acacia disticha Maslin
An uncommon species principally confined to the Fitzgerald R. Natl Park in the vicinity of Thumb Peak and Mid Mt Barren, Corackerup Ck, c. 100 km to the WSW, and in the Ravensthorpe Ra., c. 40 km to the NE, south-western W.A.
Glabrous shrub c. 1 m high, to 2 m in sheltered situations. Branchlets roughened by raised leaf bases where phyllodes have fallen. Phyllodes distichous on flattened branchlet extremities, spiral with age where branchlets are terete, elliptic, variable in size, 15–43 mm long, 4–22 mm wide, l:w = 2-4, obtuse, thin, green, imperfectly 2-nerved; lateral nerves absent or few and obscure; gland not prominent, 2–5 mm above pulvinus. Inflorescences simple or 2-headed racemes; raceme axes normally c. 4 mm long; peduncles 7–11 mm long; heads globular, loosely 6- or 7-flowered, cream. Flowers 4-merous; sepals c. 1/4 length of corolla, united into a ±truncate to sinuolately lobed calyx. Pods spreading to subretrorse by a strongly recurved stipe, narrowly oblong, to 4 cm long, 5–5.5 mm wide, crustaceous to subwoody; margins thick. Seeds (slightly immature) longitudinal, oblong, 4 mm long, slightly shiny, brown; aril terminal.
Grows along watercourses in loamy clay or sand and silt, normally in tall shrubland or Eucalyptus eremophila closed scrub where it dominates the low shrub stratum.
W.A.: Corackerup Ck, Feb. 1934, E.T.Bailey s.n. (PERTH); c. halfway between Kundip Mine and Elverton Mine, Ravensthorpe Ra., G.Craig 2011 (PERTH); Thumb Peak, Fitzgerald R. Natl Park, K.Newbey 3419 (BRI, CANB, K, MEL, NY, PERTH); 1 km N of Twin Bay, in gully leading from SW slopes of Thumb Peak, Fitzgerald R. Natl Park, B.R.Maslin 5553 (CANB, K, MO, PERTH).
A member or the ‘A. myrtifolia group’, perhaps most closely related to A. pygmaea. Sometimes sympatric with A. myrtifolia which can be distinguished by its prominently ribbed, angular branchlets, non-distichous, thicker, prominently 1-nerved phyllodes with a more prominent gland, and longer pods with clearly undulate margins.
Phyllodes vary considerably in size, even on a single specimen. On upper branchlets they are 15–30 mm long and 4–15 mm wide, whereas lower down they may reach 45 mm long and 25 mm wide.
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Minor edits by J.Rogers
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