Acacia olgana Maconochie
WATTLE
Acacias of Australia
Common Name
Mount Olga Wattle
Family
Fabaceae
Distribution
Occurs in southern N.T. from the Petermann Ranges and from around Mt Olga and Uluru / Ayers Rock in Uluru Natl Park. An anomalous record from Coward Springs, S.A. is possibly based on incorrect locality data.
Description
Shrub or small tree to 6 (sometimes 15) m high. Bark rough, slightly fissured, grey or grey-brown. Branchlets angular or flattened towards apices, light brown to reddish, mostly glabrous. Phyllodes linear to very narrowly elliptic, flat, often curved at apex, 6–18 cm long, 2–4 (–6) mm wide, coriaceous, with marginal nerve discrete, yellowish and not resinous, golden-pubescent when young, soon becoming glabrous, green, with 1 prominent central nerve; minor parallel nerves 6–11 per mm, nonanastomosing; gland 1, basal, inconspicuous. Peduncles 0–3 mm long; spikes 1.5–4 cm long, densely flowered, bright or golden yellow. Flowers 5-merous; calyx 0.5–1 mm long, dissected to at least 4/5. Pods linear, straight to slightly curved, 3.5–10 cm long, 3–4.5 (–5) mm wide, chartaceous to thinly coriaceous-crustaceous, glabrous; margins nerve-like. Seeds longitudinal to slightly oblique, broadly oblong to broadly elliptic, dorso-ventrally flattened, 2.5–3 (–3.5) x 2–2.8 mm, dark brown; areole small, pale.
Phenology
Flowers May–Sept.
Habitat
Often grows along watercourses, in gorges, crevices on rocky ranges, on sedimentary or conglomerate rocks, sometimes on sand dunes, in shrubland and woodland.
Specimens
N.T.: Valley of the Winds, Mt Olga, B.G.Briggs 3526a (CANB, NSW); Base of Ayers Rock, R.Hill & T.R.N.Lothian 740 (AD, K, NT); Petermann Ranges, P.K.Latz 1793 (DNA, NT); Olga Gorge, J.R.Maconochie 1931 & 2532 (BRI, DNA, NSW, PERTH). ?S.A.: Coward Springs, due W of Eyre Basin, 1 Sept. 1950, Knox College Exped. (no. 7 partim) (NSW).
Notes
This species has distinctively smooth, narrow, chartaceous mature pods. The ‘allied taxon with slightly broader pods’ from Kulgera and elsewhere, noted by NSW in Fl. Australia 11B: 307 (2001), is now provisionally referred to as A. subcontorta.
FOA Reference
Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia
Author
Revised by B.R.Maslin & J.Reid
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
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