WATTLE

Acacias of Australia

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Acacia ptychophylla F.Muell.

Family

Fabaceae

Distribution

An uncommon species with a disjunct distribution in northern Australia; it occurs in the eastern Pilbara and south-eastern Kimberley regions of W.A., and extends just into N.T. where it occurs in the Hooker Creek area.

Description

Dense, multistemmed, spreading, flat-topped or somewhat rounded, glabrous shrub 0.5–1 (–1.5) m high. Branchlets resin-ribbed, reddish brown but yellow or light green at extremities. Phyllodes oblong to narrowly oblong-elliptic, ascending to erect, straight or sometimes shallowly incurved, 2–4 (–5.5) cm long, (3–) 4–10 mm wide, usually with a small callose tip at apex, coriaceous, glabrous, with 5–6 (–8) rather prominent longitudinal nerves which appear raised being encrusted by resin; gland 1 small near pulvinus and 1–3 additional variably spaced glands on the upper margin. Inflorescences simple; spikes erect, 2–4.5 cm long, bright golden; peduncles 15–30 mm long. Flowers 5-merous; calyx dissected to ½–3/4 its length. Pods narrowly oblong to oblong-elliptic but narrowed towards the base, straight or shallowly curved, 5–7 cm long, flat, woody, encrusted with resin, obliquely longitudinally nerved; margins distinct, light brown. Seeds oblique, oblong-elliptic, 4–5 mm long, brown; pleurogram dark; areole open, depressed; funicle-aril turbinate, straight, white.

Phenology

Flowers Mar.–Aug. with main flush May–June.

Habitat

Grows mostly on rocky slopes or sand plains, associated with spinifex (Triodia pungens) communities.

Specimens

W.A.: Tom Price, B.R.Maslin 4665 (CANB, K, PERTH); The Pilbara, near S end of Gorge Ra., Great Northern Hwy, 1.5 miles [2.4 km] S of Coongan R., I.V.Newman 686 (NSW, PERTH); 0.8 km from Balgo Mission, Great Sandy Desert, A.R.Peile 7 (PERTH). N.T.: 15 km N of Hooker Creek [Stn], P.L.Wilson 993 (DNA).

Notes

An attractive species when in flower and would make a suitable rockery and/or ground cover plant for inland gardens.

FOA Reference

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

Author

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

Revised by B.R.Maslin