Acacia extensa Lindl., Sketch Veg. Swan R. xv (1839)
Spindly, open, glabrous shrub to 3 m high, occasionally semi-weeping. Branchlets angled, often flattened at apices, sometimes narrowly winged, green, with yellowish ribs. Phyllodes often few, distant and resembling the branchlets, frequently filiform, slender, normally pentagonal in section, rarely flat, 6–24 cm long, 0.8–1.8 mm wide, with somewhat indurate mucro, with 5 prominent, yellowish nerves, the adaxial 2 forming a broad upper margin. Inflorescences comprising racemes resembling the branchlets, sometimes simple; peduncles 3–8 mm long; heads globular, 12–24-flowered, light golden. Flowers 5-merous; sepals united to near apex; petals 1-nerved. Pods linear, submoniliform, straight to shallowly curved, to 9 cm long, 3–4 mm wide, firmly chartaceous to thinly coriaceous. Seeds longitudinal, oblong to oblong-elliptic, 4–5 mm long, shiny, dark brown; aril apical.
Widely distributed from near Mogumber S to Albany, south-western W.A. Grows in sand, laterite, sand over laterite, sandy loam and gravelly sand, in the understorey of mainly eucalypt forest along watercourses.
Besides the names given in synonymy below, a number of other names, presumably unpublished, appear on specimens of A. extensa at various European herbaria, viz. A. balsamea (WU), A. balsamifera (FI), A. caetinsa (MPU) and A. howardii (L).
Included in sect. Pulchelloidea by J.Vassal, Bull. Soc. Hist. Nat. Toulouse 108: 1- 127 (1972); this section combined both phyllodinous and bipinnate-leaved species.
Type of accepted name
Swan R., W.A., J.Drummond s.n. ; syn: CGE; isosyn: K. Vasse River, G.Molloy s.n .; syn: CGE; isosyn: K.
Acacia graminea Lehm. ex Meisn., in J.G.C.Lehmann, Pl. Preiss . 1: 5 (1844); A. graminea Lehm., Del. Sem. Hort. Hamburg 1842: 3 (1842), nom.nud. Type: near Mahogany Creek, Darling Ra., W.A., L.Preiss 984 ; lecto: LD, fide B.R.Maslin & R.S.Cowan, Nuytsia 9: 406 (1994); isolecto: A, G, NY; Swan R., J.Drummond 304 ; paralecto: BM, OXF, P.
Acacia pentaedra Regel, Flora 35: 417 (21 July 1852); Gartenflora 1: 228 t. 24 (Aug. 1852). Type: cultivated at Zurich Botanic Garden under the name A. odorata and A. viminea, probably originating from the Swan R., W.A. Synonymy following G.Bentham, Fl. Austral . 2: 340 (1864).
Acacia calamistrata hort. ex Jacques, J. Soc. Imp. Centr. Hort . 8: 344 (1862). Type: cultivated, hort. Paris, flowering in Feb. 1862; n.v.
J.Lindley, loc. cit .; E.Regel, loc. cit. ; O.Stapf & F.Ballard, Bot. Mag. 153: t. 9172 (1929); M.Simmons, Acacias Australia 81 (1981).
W.A.: 3 km S of Porongurup Ra., R.H.Kuchel 1955 (PERTH); c. 3.5 km below Mundaring Weir, Helena R. Valley, B.R.Maslin 671A (CANB, PERTH); Darling Ra., L.Pritzel 532 (B, BM, E, G, L, LY, M, NY, P, PR, Z).