WATTLE

Acacias of Australia

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Acacia ayersiana Maconochie

Common Name

Ayers Rock Mulga, Broad-leaf Mulga, Uluru Mulga

Family

Fabaceae

Distribution

Wide ranging from W.A. to southern parts of N.T. and S.A.

Description

Rounded or obconic, multi-stemmed shrubs 3–6 m tall and about the same across, sometimes single-stemmed trees 7–12 m tall. Branchlets with dense white appressed-pubescence between red-brown ribs, the ribs sometimes with a thin veneer of translucent resin; new shoots not or scarcely resinous (except for margins of young phyllodes), usually densely sericeous with hairs normally pale yellow. Phyllodes narrowly elliptic to lanceolate, straight but often shallowly recurved at apex or occasionally over entire length, (3–) 5–8 (–10) cm long, (4–) 7–12 (–18) mm wide, acute to acuminate, commonly silvery light grey-green ageing dull green, longitudinal nerves numerous with 3–6 nerves slightly more pronounced than the rest (best observed on young phyllodes); marginal nerve discrete and resinous, light brown to red-brown but often ageing dull yellow. Inflorescences single in axils; peduncles 3–6 (–8) mm long; spikes (10–) 15–35 mm long. Flowers 5-merous; sepals ¼–⅓ length of corolla, free or shortly united at base; corolla 1.3–1.7 (–2) mm long. Pods shortly stipitate, oblong, 1–4 cm long, 10–14 (–17) mm wide including wings 1–2 mm wide, chartaceous, brown, reticulately nerved, glabrous or minutely appressed-pubescent, dehiscent. Seeds transverse to oblique, oblong, 5–6 mm long, 2.5–3 mm wide; aril small, terminal, oblique, pileate, white.

Habitat

Usually grows on sandy soils, often in swales of dunes.

Specimens

W.A.: 38 miles [61 km] E of Mount Magnet, B.A.Barlow 343 (AD); Hamersley Ra., c. 59 km W of Newman on rd to Port Hedland, B.R.Maslin 8031 (CANB, PERTH). N.T.: 19 miles [30 km] W of ‘Curtin Springs’, M.Lazarides 6177 (BRI, CANB). S.A.: S of Musgrave Ranges, Mt Wood-Mt Harriet, 30 Sept. 1955, S.A. Pastoral Board (AD); Flinders Ranges, L.D.WIlliams 11537 (AD).

FOA Reference

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

Author

L.Pedley

Revised by B.R.Maslin