Acacia retinodes

Acacia retinodes Schltdl., Linnaea 20: 664 (1847)

Shrub or tree 5–10 m high. Branchlets sometimes pendulous, often angled or flattened, glabrous, sometimes lightly pruinose. Phyllodes normally oblanceolate to narrowly oblanceolate, 3–22 cm long, 3–15 mm wide, sometimes uncinate, thin, green to glaucous, glabrous, 1-nerved per face, obscurely penninerved; gland not prominent, 1–16 mm above pulvinus; pulvinus 2–4 mm long. Inflorescences racemose; raceme axes normally 0.7–4 cm long, glabrous; peduncles 2–7 mm long, rather slender, glabrous; heads globular, 18–50-flowered, cream, pale yellow or golden; bracteole laminae 0.3–0.5 mm diam., not prominent in buds. Flowers 5-merous; sepals united to near apex. Pods linear, to 16 cm long, 5–11 mm wide, firmly chartaceous to thinly crustaceous, glabrous. Seeds longitudinal, oblong to oblong-elliptic, 4–6 mm long, dull to slightly shiny, dark brown to black; funicle 3/4 or more encircling seed, red-brown to blackish; aril clavate.

Discontinuous in south-eastern Australia from the Eyre Penin., S.A. to Wilsons Promontory, Vic., also King and Flinders Islands, Tas. Seemingly absent between the Murray and Glenelg Rivers.

See note under A. semperflorens Jacques under Doubtful Names in Fl. Australia vol. 11, 2001.

A member of the ‘ Acacia microbotrya group’ perhaps most closely allied with A. confluens , A. leiophylla and A. rivalis ; also related to A. gillii . Acacia semiaurea is possibly a hybrid involving A. retinodes and either A. argyrophylla or A. brachybotrya (appressed-hair variant) . Acacia provincialis was described as a garden hybrid between A. retinodes and A. cyanophylla (= A. saligna ); the flowering syntypes of this name strongly suggest that this entity is A. retinodes var. retinodes with slightly broader than normal phyllodes (to c. 2 cm wide); they have none of the diagnostic gland or raceme bract characters of A. saligna . Phyllodes sometimes resemble those of A. mabellae .

Details of the breeding system are discussed in the papers of J.Kenrick & R.B.Knox, e.g. Theor. Appl. Genet. 69: 481–488 (1985). A widely cultivated, fast-growing but short-lived hardy species with unobtrusive flowers that occur sporadically throughout much of the year but with the main flush in spring and summer.

Most specimens referable to A. retinodes can be accommodated within the three taxa that are now recognized, namely, var. retinodes (comprising a "typical" and a "swamp" variant) and var. uncifolia .  For the most part the two varieties are allopatric with var. uncifolia occurring on coastal dunes and var. retinodes occurring on hillsides or along watercourses inland. However, in a few places in S.A. their ranges abut, for example, at Normanville where var. retinodes (typical variant) and var. uncifolia appear to hybridize, and on Kangaroo Is. where var. retinodes (swamp variant) and var. uncifolia occur (but do not hybridize). Hybrids between the two variants of var. retinodes are extremely rare.  A key to the recognition of these three taxa follows.

Heads mostly  34–52-flowered, yellow to golden; branchlets often lightly pruinose; phyllodes blue-green to blue-grey, often lightly pruinose, 6-22 cm long

var. retinodes (swamp variant)

Heads mostly 18–30-flowered, cream to pale yellow; branchlets not pruinose; phyllodes green or grey-green, not pruinose

     Phyllodes 3–6 cm long; pods 5–7 (–8) mm wide; coastal habitats

var. uncifolia

     Phyllodes 6–16 cm long; pods 8–11  mm wide; hillside habitats

var. retinodes (typical variant)

Acacia retinodes Schltdl. var. retinodes

Wirilda , Swamp Wattle , Silver Wattle , Ever-Blooming Wattle , and more

Bushy or open shrub or tree 6–8 m high. Branchlets often pendulous, lightly pruinose or not. Phyllodes narrowly elliptic to oblanceolate, 6–22 cm long, 3–25 mm wide, normally gradually narrowed to an acute or acuminate, straight or sometimes subuncinate apex, glaucous to grey-green or green. Heads normally 18–52-flowered, cream, pale yellow or golden. Pods 5–11 mm wide.

Occurs on Kangaroo Is. and Mt Lofty Ra., S.A., and from the Glenelg R. to near Melbourne, Vic.

Two distinct variants have recently been recognized within var. retinodes .

Acacia retinodes Schldl. var. retinodes (typical variant)

Silver Wattle

Typically a small upright tree with an erect branching habit, suckering habit present. Bark rough and furowed, black-brown bark. Branchlets not pruinose. Phyllodes typically narrowly oblanceolate, mostly 6–16 cm long, 3–12 (–16) mm wide, green to grey-green, not pruinose, crowded on branchlets; gland 0–3 (–7) mm above pulvinus. Heads cream to pale yellow, mostly 18–30-flowered. Pods 8–11 mm wide.

Restricted to the Mt Lofty Ranges, S.A., where it extends from Mount Bryan south through the Barossa Valley, Adelaide Hills and to Delamere, Fleurieu Peninsula. Grows in fertile soils and on rocky hillsides and loamy flats, away from water. This species has become locally naturalised near Mt Gambier, south eastern S.A., where original plantings have spread to form small colonies. Flowers in summer.

Type of accepted name

‘Sehr verbreitet auf fruchtbarem Boden in der Nahe des Wassers im den Thalern.’ [Barossa Valley, S.A., perhaps from Schlinckens Ck], H.H.Behr s.n. ; holo: HAL; iso: MEL616152.

Synonymy

Acacia retinodes var. floribunda H.Vilm., J. Roy. Hort. Soc. ser. 2, 16: 84, fig. 2 (1894), nom. inval. (name not accepted by the author in text on p. 85); fide O.Stapf & F.Ballard ser. 2, Bot. Mag . 153: t. 9177 (1929).

Acacia floribunda hort. ex G.Nicholson, Ill. Dict. Gard. , Cent. Suppl. 4 (1900), pro syn. sub A. retinodes , non (Vent.) Willd. (1806).

Acacia fragrans hort. ex Pottier, Jardin 22: t. 72, fig. 2 (1908), nom.nud. , non Ten. (1845); fide O.Stapf & F.Ballard, loc. cit.

Acacia semperflorens horti ex A.Berger, Hort. Mortol. 7 (1912), pro syn. sub A. retinodes .  See also Acacia semperflorens Jacques and Mimosa semperflorens Anon. under Doubtful Names.

Acacia longissima hort. ex Chopinet, Ann. Inst. Natl. Rech. Agron., Ser. B, Ann. Amelior. Pl . 1 (4): 603 (1951), pro syn. sub A. retinodes , non hort. ex H.L.Wendl. (1820).

Acacia provincialis A.Camus pro hyb., Bull. Soc. Dendrol. France 64: 68, figs (1927). Type: cultivated at Pampelonne, commune de Ramatuelle, Mar. 1927, A. Camus ; syn: P, see note below.

 Illustration

C.D.Boomsma, Native Trees of South Australia 76 (1981).

Representative collections

S.A.: Mt Bryan, M.O'Leary 2729 (AD); Tarnma Creek, Tothill Ra., D.N.Kraehenbuehl 5386 (AD); c. 16 km SW of Eudunda, B.Copley 3300 (AD, L, Le, M, MEL); NE of Tanunda, D.N.Kraehenbuehl 1848 (AD, L, NY, PRE, W); Anstey Hill Rec. Park, A.G.Spooner 10577 (AD); Mt. Barker - Wistow Rd., N.M.Smith 2637 (AD, PRE, PTBG); Bull Creek - Ashbourne Rd., 21/1/1975, D.Pethick (AD, NSW).

Acacia retinodes Schldl. var. retinodes (swamp variant)

Swamp Wattle

Tree of variable habit, the crown spreading and either openly branched or dense. Bark smooth, grey. Branchlets often lightly pruinose. Phyllodes 6–22 cm long, (3–) 4–25 (-35) mm wide, narrowly elliptic to oblanceolate, blue-green to blue-grey, often lightly pruinose, less crowded on branchlets than the "typical variant"; glands 0–16 mm above pulvinus. Heads yellow to golden, mostly 34–52-flowered. Pods 5–7 mm wide, often lightly pruinose.

Occurs from near Mt Crawford through the Fleurieu Peninsula, Kangaroo Island and far south-eastern S.A., eastwards to the Grampians, Glenelg R. and near Melbourne in Vic. Grows in damp soils in swamps and along watercourses. Flowering peak is from spring to summer, with scattered flowering occurring throughout the year.

Some plants from western Kangaroo Island have an erect spindly habit, large leathery phyllodes with up to four glands, and more pruinose branchlets and pods.

Illustrations

F.Mueller, Iconogr. Austral. Acacia dec. 5 [pl. 9] (1887); D.J.E.Whibley & D.E.Symon, Acacias S. Australia 2nd edn, 143 (1992).

Representative collections

S.A.: Morialta, 1/2/1924, E.H.Ising (AD); Waterfall Gully, H.J.Eichler 14589 (AD, CANB, P, PRE, NY); Cox's Scrub, B.C.Crisp 60 (AD, PERTH); Finniss R., D.J.E.Whibley 10435 (AD); Flinders Chase, M.O'Leary 2595 (AD). Vic. Victoria Ra., L.Haegi 636 (AD, MEL, CANB, NSW, A, AAU, H, L, SI); Grampians, S.T.Parfett 13 (AD, MEL, NSW, PERTH); Victoria Valley near Halls Gap, Grampians, D.J.E.Whibley 3378 (AD); Banks of Glenelg R. at junction of Moleside Ck, 10 Nov. 1963, J.H.Willis s.n. (MEL).

Acacia retinodes var. uncifolia J.M.Black (as ‘rhetinodes’), Trans. & Proc. Roy. Soc. S. Australia 56: 42 (1932)

Bushy shrub or tree 5–10 m high, often spreading by runners and coppicing to form dense groves. Branchlets not pruinose.  Phyllodes oblanceolate to narrowly oblanceolate, 3–6.5 cm long, 3–10 mm wide, rather abruptly narrowed at the uncinate to subuncinate apex with a distinct and delicate mucro, green. Heads 18–30-flowered, pale yellow or cream. Pods 5–7 (–8) mm wide.

Occurs on the southern Eyre Penin., Kangaroo Is. and Fleurieu Penin., S.A., also Geelong to Wilsons Promontory, Vic., and King and Flinders Islands, Tas. On coastal dunes, and sandy soils over limestone.

Phyllodes sometimes similar to those of A. flocktoniae (N.S.W.). They also resemble some individuals of A. euthycarpa .

A detailed discussion of var. uncifolia in Tasmania is given in A.J.J.Lynch (1993), Conserv. Biol. & Managem. of 16 Rare or Threat. Fabaceae Species Tas. (ANPWS Endangered Species Program Project No. 4: 41–47, 1993). It should be noted, however, that the flowering branch shown in Figure 5.1 of this work depicts the typical variety.

Type of accepted name

Waitpinga Rd, S.A., 25 Jan.1932, J.B.Cleland ; holo: AD; iso: AD, K.

Illustrations

L.F.Costermans, Native Trees & Shrubs SE Australia 319 (1981); D.J.E.Whibley & D.E.Symon, Acacias S. Australia 2nd edn, 143 (1992).

Representative collections

S.A.: near Cygnet R., Kangaroo Is., G.Jackson 473 (AD); Port Lincoln, herb. R.Tate (AD 97422170). Vic.: Cape Schanck area, c. 14 km due W of Flinders, B.R.Maslin 5473A (CANB, MEL, PERTH). Tas.: Currie, King Is., 28 Jan. 1971, P.Barnett s.n. (MEL).

(BRM)

The Fl. Australia treatment of A. retinodes has been modified here in WATTLE to accommodate the two variants which are now recognized as comprising var. retinodes.

The information presented here originally appeared on the WATTLE CD-ROM which was jointly published by the Australian Biological Resources Study, Canberra, and the Department of Parks and Wildlife, Perth; it was produced by CSIRO Publishing from where it is available for purchase. The WATTLE custodians are thanked for allowing us to post this information here.