WATTLE

Acacias of Australia

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Acacia gonocarpa F.Muell.

Family

Fabaceae

Distribution

Occurs in northern N.T. from Melville Is. S to Darwin and Kakadu Natl Park, and in the Kimberley region of W.A.

Description

Shrub to 2 m high, sometimes a tree to 3.5 m high, erect, many-stemmed, spindly or spreading, often with drooping branches and sparse canopy. Bark smooth but finely fissured at base of trunk. Branchlets angled or flattened, later terete; ridges minutely convoluted, translucent. Phyllodes single or sometimes in 2s or 3s, linear to narrowly elliptic, straight or upcurved, (1.2–) 5–12 (–14.5) cm long, 0.7–1.8 mm wide (2–5 mm wide in variants), with minute apical mucro, moderately stiff, with prominent longitudinal midnerve. Spikes 1–3 in phyllode axils, to 3 cm long, interrupted, pale yellow or cream. Flowers 5‑merous, rarely 4‑merous; sepals free, 0.4–0.7 mm long, spathulate, glabrous; corolla 0.7–1 mm long, dissected to c. 1/2; petals recurved, with distinct midribs and thickened apices. Pods straight or curved, 2–8.5 cm long, 3–6 (–10) mm wide, ±woody, dark brown, with wings 2–4.5 mm wide and often convoluted. Seeds oblique, brown; funicle-aril straight, conical.

Phenology

Flowers Oct.–Feb.

Habitat

Grows in open eucalypt or mixed woodland, sometimes with Melaleuca nervosa, on top of sandstone escarpments or on the lower slopes or alluvial fans, sometimes on laterite, on sandy, gravelly soil.

Specimens

W.A.: Mitchell Plateau, 9 km W of Mitchell Falls, B.R.Maslin 5087 (CANB, NSW, PERTH). N.T.: near Jabiru, W.Bishop 812 (AD, B, K, MEL, MO, NSW, TL, US); Melville Is., N.Byrnes 2793 (BRI, CANB, DNA, NSW); Cox Peninsula, Port Darwin, N.Holtze 2027 (NSW); near the end of Arnhem Hwy, Jabiru, M.D.Tindale 10007, K.Brennan & P.Munns (BRI, MEL, NSW, PERTH).

Notes

There are several variants allied to A. gonocarpa from W.A. and the N.T. requiring investigation; some of these resemble A. richardsii which is distinguished by its phyllodes having a rather well-developed reticulum between the few longitudinal nerves (nerves all parallel or occasionally a few anastemoses developed in A. gonocarpa).

FOA Reference

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

Author

Minor edits by J.Rogers

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