Acacia hopperiana Maslin
Acacia hopperiana Maslin
Occurs in the Carnamah–Watheroo area, N of Wubin and from Nerren Nerren Stn S to near Murchison River, N of Geraldton, in south-western W.A.
Shrub 1–3 m high, occasionally tree to 4 m high. Branchlets sericeous between ribs at extremities, glabrescent. Phyllodes ascending to erect, straight to shallowly incurved, terete, 6–14 cm long, 0.7–1 mm wide, innocuous to coarsely pungent, subrigid, light green, appressed-puberulous when young, glabrous or hairs confined to furrows with age; nerves 10, broad, ±flat-topped and of uniform width, each separated by a shallow, narrow, dark-coloured (when dry) furrow; not prominent, sometimes absent, 10–60 mm above pulvinus. Inflorescences simple, 1 or 2 per axil; peduncles 1–3 mm long, appressed-hairy; spikes 10–20 (25) mm long, subdensely flowered, golden. Flowers 4-merous; sepals 1/2–3/4 united. Pods flat, moderately to deeply constricted between seeds, 5–9 cm long, 2–3 mm wide, thinly coriaceous-crustaceous to firmly chartaceous, greyish brown, glabrous or antrorsely strigulose. Seeds longitudinal, oblong-elliptic or discoid, 2–3 mm long, glossy, mottled or not mottled; aril ±conical, white.
Grows in sand on plains or in swales between sand dunes, occasionally found in loam near rock.
W.A.: 20 km ESE of Coorow, 9 Aug. 1987, A.Doley (PERTH); 70 km N of Northampton, R.Hnatiuk 760473 (PERTH); Buntine Rock, NNW of Wubin, B.R.Maslin 7605 (CANB, K, MEL, PERTH); Nerren Nerren Stn, 6 km N of Kalbarri Natl Park, S.Patrick & A.Brown SP1999 (PERTH).
Specimens of A. hopperiana from N of Geraldton have clearly discoid seeds with readily detaching arils, while those S of Geraldton have obloid-ellipsoid seeds with arils not so readily detaching.
Most closely related to, and easily confused with, A. isoneura which is most reliably distinguished by its 8-nerved phyllodes with obscure gland 0–3 mm above the pulvinus, reddish brown pods and ellipsoid to obloid-ellipsoid seeds (never discoid).
This species was noted under A. isoneura by A.R.Chapman & B.R.Maslin, Fl. Australia 11B: 355 (2001) but was formally recognized too late to be fully described in that volume.
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
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