Acacias of Australia

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Acacia incognita Maslin & Buscumb

Common Name

False Sugar Brother




Occurs in the Mullewa and Yalgoo areas, S to Karara Stn (c. 80 km E of Morawa), W.A.; often locally common.


Obconic shrub or tree 3–5 m high, stems slightly crooked and not fluted. Bark fissured on main stems and normally also upper branches. New shoots resinous, glabrous except often with scattered, caducous, reddish glandular hairlets. Branchlets glabrous or obscurely appressed-puberulous between obscure, non-resinous ribs. Phyllodes slender, sub-terete to flat, sometimes terete, innocuous to coarsely pungent, straight to shallowly incurved, (4–) 7–12 cm long, (0.8–) 1–1.2 (–1.5) mm wide, not especially rigid, green or sometimes greyish green; longitudinal nerves fine, numerous and close together. Inflorescences simple, 1 (–2) per axil; peduncles usually (3–) 4–6 (–7) mm long, slender, glabrous or sometimes sub-glabrous; heads globular to short-obloid, 4–6 mm long, 4–5 mm diam., golden. Flowers 5-merous; sepals free to 1/4 united. Pods straight to shallowly curved, terete, mostly slightly constricted between seeds, 3.5–10 cm long, 1–2 mm wide, thinly coriaceous-crustaceous, ±obscurely longitudinally nerved. Seeds longitudinal, narrowly elliptic or narrowly oblong, 3–5 mm long, shiny, brown; aril white to creamy white.


Flowers erratic between Jan. and Oct.


Grows in loam or loamy clay on plains or low rises, in woodland dominated by Eucalyptus spp. or shrubland dominated by Melaleuca spp.


W.A.: 36 miles [58 km] S of Yalgoo, J.S.Beard 7189 (PERTH); Karara Station, c. 1 km W of Mount Karara, D.Coultas, F.Obbens & C.Anderson AS-02 (AD, PERTH); 48 km W of Yalgoo on the road to Mullewa, B.R.Maslin 7110 (CANB, NSW, NY, PERTH).


A member of the ‘A. coolgardiensis group’ and sometimes sympatric/parapatric with other group members, A. effusifolia and A. latior.

Collections previously noted by R.S.Cowan, Fl. Australia 11B: 329 (2001), from Carey Downs, Byro and Curbur stns, W.A. have been provisionally referred to A. incognita but differ from typical representatives of the species in having terete phyllodes and longer peduncles (5–12 mm long) and receptacles (to 7 mm long); further study is required to assess the status of these plants, see B.R.Maslin & C.Buscumb, Nuytsia 18: 118 (2008), for discussion.

Most closely related to A. coolgardiensis which differs in having fluted stems, mostly smooth bark, often resin-ribbed branchlets, never flat phyllodes, generally larger heads that are normally obloid to short-cylindrical and mostly paired in axils and shorter, stouter peduncles; see B.R.Maslin & C.Buscumb, Nuytsia 18: 117 (2008) for further discussion. Superficially similar to A. resinosa which is most readily recognised by its resinous heads, united sepals and flat, non-striate pods, and a variant with close affinities to A. balsamea that occurs near Lake Giles.

FOA Reference

Flora of Australia Project


J.Reid, B.R.Maslin