Flora of Australia Online

Acacia rostellifera Benth., London J. Bot. 1: 356 (1842)

T: Swan R., W.A., J.Drummond 103 ; probable holo: K, fide A.R.Chapman & B.R.Maslin, Nuytsia 8: 272 (1992).

Acacia subbinervia Meisn., in J.G.C.Lehmann, Pl. Preiss. 1: 16 (1844). T: Rottnest Is., W.A., 20 Aug. 1839, L.Preiss 924 ; lecto: LD, fide B.R.Maslin & R.S.Cowan, Nuytsia 9: 412 (1994); isolecto: C, G, GOET, HBG, L, M, NAP, NSW, P, STR, W; Swan R., W.A., J.Drummond 285 ; paralecto: BM (sheet labelled herb. Shuttleworth), G, K, P, W.

Acacia cyanophylla var. dorrienii Domin, Vestn. Král. Ceské Spolecn. Nauk, Tr. Mat.-Prír. 2: 46 (1923). T: Yallingup and Cape Naturaliste, W.A., 1900, A.A.Dorrien-Smith ; holo: PR.

[Acacia salicina auct. non Lindl. (1838): B.P.G.Hochreutiner, Candollea 2: 375 (1925), as to Hochreutiner 2880 , Z]

Illustrations: M.Simmons, Acacias Australia 153 (1981); A.R.Chapman & B.R.Maslin, 8: 250, fig. 1d & 271, fig. 5c (1992).

Dense shrub or tree to 6 m high, often clonal. Bark dark grey and fissured on main trunks. Branchlets glabrous, scurfy. Phyllodes linear to linear-elliptic or narrowly oblanceolate, 4.5–11.5 cm long, 3–17 mm wide, l:w = 4–30, uncinate to subuncinate, sometimes excentrically rostellate, thin, frequently puncticulate, glabrous, 1-nerved or imperfectly 2-nerved; lateral nerves obscure; glands not prominent, 4–12 mm above pulvinus, often also at base of mucro. Inflorescences 3–9 headed racemes; raceme axes 1–3 cm long; peduncles 3–8 mm long, glabrous; heads globular, 5–7 mm diam., to 10 mm when fresh, subdense, 15–25-flowered, golden. Flowers 5-merous; sepals united into a shallowly lobed or sinuate-toothed calyx. Pods ±erect, submoniliform, to 9 cm long, 5–7 mm wide, firmly crustaceous, breaking readily at constrictions. Seeds longitudinal, oblong to widely elliptic, 4–6 mm long, dull or shiny, dark brown; aril prominent, twice-folded, orange or red. Fig. 46C–E.

Occurs in coastal areas of south-western W.A. from Shark Bay S to Cape Naturaliste and from Bremer Bay E to Israelite Bay. At the northern end of the range it extends inland to Latham. Grows in sand, frequently on dunes, where it may form monotypic stands. Map 245.

W.A.: 24.2 km S of Billabong on North West Coastal Hwy, M.E.Ballingall 1896 (BRI, PERTH); 6 km inland of Point Malcolm, R.Hnatiuk 761133 (PERTH); 8 km S of Geraldton towards Perth, B.R.Maslin 75 (PERTH); near Fitzgerald R. crossing, Fitzgerald R. Natl Park, B.R.Maslin 3480 (PERTH); Cape Naturaliste Lighthouse, L.Nunn 544 (PERTH).

A member of the ‘A. bivenosa group’. Although A. rostellifera is somewhat variable in phyllode shape and size (e.g. see A.R.Chapman & B.R.Maslin, Nuytsia 8: 250 (1992)) it is distinguished from its closest relatives by a combination of the following characters: branchlets scurfy, phyllodes thin, green, frequently puncticulate (i.e. possessing minute brown peltate glandular hairs which seem to leave obscure shallow depressions in the phyllode surface), 1-nerved or with a very faint second nerve, uncinate to subuncinate and with a distinct mucro. Specimens from around the Murchison R. have distinctly 1-nerved, narrow phyllodes (3–6 mm wide) and shorter racemes with consistently fewer flower-heads than normal. This variant extends to Shark Bay where it can be confused with A. ligulata . Also closely related to A. xanthina , with which it appears to hybridise near Jurien Bay. Narrow, green phyllode forms of A. blakelyi may resemble A. rostellifera , but are readily distinguished by their horizontally flattened phyllodes with the gland situated on the adaxial surface (not on the adaxial margin as in A. rostellifera ).

(A.R.Chapman, B.R.Maslin)