Acacia aneura

Acacia aneura F.Muell. ex Benth., Linnaea 26: 627 (1855)

Mulga

Shrub or tree to 18 m tall. Branchlets with white-appressed and red-glandular hairs between resinous ribs that sometimes become beaded with age; new growth dark (red-) brown, sometimes fuligneous, resinous. Phyllodes straight or ± curved, terete to flat, 2.5–9 (–12.5 ) cm, long, 0.8–9 mm diam./wide, striate with longitudinal nerves, appressed pubescent between them, often glabrescent, occasionally resinous. Inflorescences single in axils; peduncles 3–10 mm long; spikes 7–30 mm long. Flowers 5-merous; sepals spathulate or oblong, 0.5–1.1 mm long, free or united in basal ring or rarely with extremely short tube usually with a few hyaline hairs at top; corolla 0.9–1.8 mm long, glabrous or rarely with sparse short-appressed hairs towards lobe tips; stamens 2–3.5 mm long; ovary with dense scale-like appressed hairs, occasionally resinous and apparently glabrous. Pods stipitate, oblong, flat, straight, to 10 cm long, 7–17 mm wide, chartaceous or somewhat crustaceous, often brown and resinous when mature, reticulately nerved, sometimes only faintly so, with resinous marginal nerves or a wing to 2 mm wide, glabrous or subglabrous. Seeds oblique to transverse, oblong or oval, 3–6 mm long, 2.2–4.5 mm wide; aril distinct, small, obliquely terminal, pileate, creamy white.

Widely spread in all mainland States except Vic., mainly S of 20° latitude from the Indian Ocean almost to the Great Dividing Ra. in central Qld and in N.S.W.; usually on loamy or sandy soils in areas of low relief or on shallow rocky soils on hills. Often in pure stands forming open forests, woodlands and shrublands or predominant in vegetation with eucalypts, often with shrubby understory. A prominent and conspicuous element of the landscape that has given rise to such terms as ‘mulga country’, ‘mulga lands’ or merely ‘the mulga’. Of great economic importance, particularly to the pastoral industry, most variants being palatable to grazing animals, native and exotic.

A species with a bewildering degree of variability that requires detailed investigation, both in the field and in the herbarium. A single stand may contain several distinct variants, but intermediates between these variants can often be found in other, more distant, stands. The situation is possibly similar to that of Senna artemisioides and S. glutinosa treated as 'form taxa' and discussed at some length in the Flora of Australia 12: 104, 105 (1998). A. aneura also intergrades over wide areas, particularly in the western half of its range, with other species of the complex, notably A. ayersiana and A. minyura , and hybrids with other species occur, particularly A. ramulosa and A. craspedocarpa . (Specimens usually referred to A. brachystachya in the west of W.A. are for the most part, hybrids between A. aneura and A. ramulosa .) In view of the variability within the species and the common occurrence of intergrades with other species, it could be argued that the circumscription of A. aneura should be widened to include not only A. ayersiana and A. minyura but also A. paraneura . Over most of their geographic ranges these species are, however, distinctive and easily distinguished from A. aneura , and recognising one hugely polymorphic species would have no practical or scientific value. Although A. catenulata was included in the Mulga complex by L.Pedley, Trop. Grasslands 7: 4 (1973) it is probably more closely related to A. shirleyi . Acacia coolgardiensis is probably related to the A. aneura group of species.

Ten varieties of A. aneura are recognised, however, and others will probably be described when suitable herbarium material is available. The following key is merely a guide to the identification of the varieties recognised, and may be found deficient, especially for plants from W.A. where the variation within the species and the intergrades among varieties have proved difficult to accommodate in an orthodox taxonomic treatment. It is important that mature intact phyllodes be used when measurements are taken, as damaged ones are often seriously distorted.

Key

1 Phyllodes terete or slightly flattened laterally, usually 0.6–1.2 mm diam, or if up to 1.8 mm diam. slightly hooked at tip; pods not winged or wings to 1 mm wide

2 Phyllodes crowded towards ends of branches, some in 2s and 3s arising from single point; mature trees with horizontal branches (‘pine-tree’ habit)

var. conifera

2: Phyllodes single, not crowded towards ends of branches; mature trees usually with obliquely ascending branches, not with ‘pine-tree’ habit

3 Pods to 10 cm long, 10–20 mm wide, often with a distinct marginal rim, not winged. Seeds c. 6 mm long, 5 mm wide

var. macrocarpa

3: Pods to 6 cm long and 10 mm wide, wing to 1 mm wide or wing lacking; seeds smaller, either shorter or narrower

4 Pods 5.5–8.5 mm wide, including wing 0.6–1 mm wide; phyllodes straight to strongly curved, usually slightly hooked at apex

var. microcarpa

4: Pods to 10 mm wide, wing lacking or to 0.5 mm wide; phyllodes straight to strongly curved, not hooked at apex

5 Branchlets brown with strongly resinous ribs; pod to 3 cm long, 7–10 mm wide with resinous marginal nerves or wing to 0.5 mm wide, shining at or slightly before maturity

var. tenuis

5: Branchlets yellowish, not strongly resinous; pod to 6 cm long, c. 7 mm wide (not seen mature), not winged

var. pilbarana

1: Phyllodes flat, 1–13 mm or more wide, apex not hooked, or if less than 1.8 mm wide then sometimes slightly hooked; pods not winged or wings to 3 mm wide

6 Phyllodes crowded towards ends of branches, some in 2s and 3s arising from a single point; mature trees with horizontal branches (‘pine-tree’ habit)

var. conifera

6: Phyllodes not particularly crowded towards the end of the branches, arising singly

7 Pods with wing 1 mm or more wide; corolla glabrous

8 Branchlets densely appressed pubescent, hairs usually obscuring ribs; phyllodes usually (2.5–) 3–8 (–13) mm wide, 3.5–20 (–25) times longer than wide

var. major

8: Branchlets pubescent, but indumentum not obscuring ribs; phyllodes 1–4.5 (–6) mm wide, 20–95 times longer than wide

9 Phyllodes 2.5--4.5 (--6) mm wide, 20--40 (--45) times as long as wide, not hooked at apex

var. intermedia

9: Phyllodes 0.8--1.8 mm wide, (20--) 30--95 times as long as wide, usually hooked at apex

var. microcarpa

7: Pods not winged or wing to c. 0.4 mm wide; corolla sometimes with a few short appressed hairs on lobes

10 Phyllodes to c. 2.2 mm wide; corolla glabrous; pod wing absent or rarely to 0.4 mm wide

var. aneura

10: Phyllodes 3 mm or more wide. Corolla sometimes with a few appressed hairs on lobes; pods with resinous marginal nerves, not winged

11 Foliage not markedly silver-grey; new growth conspicuously dark red-brown with dense glandular hairs persisting on developing phyllodes; phyllodes usually 3–6 mm wide, 6–20 times longer than wide. Corolla c. 2 mm long, sometimes with appressed hairs on lobes

var. fuliginea

11: Foliage silvery grey; new growth dark red-brown for only a short period, glandular hairs not persisting on developing phyllodes; phyllodes usually 5–8 mm wide; corolla to 1.6 mm long, glabrous

var. argentea

 

Acacia aneura F.Muell. ex Benth. var. aneura

Shrub or tree to 4 (–6) m tall. Branchlets with white appressed and red-glandular hairs between resinous ribs. Phyllodes straight or curved, flat or rarely subterete, 3–9.5 cm long, 1–2 (–2.2) mm wide. Flowers with sepals 0.7–1 mm long; corolla 1.3–1.5 mm long; stamens 2–3 mm, occasionally to 3.5 mm, long. Pods flat-oblong, to 4 cm long, 6–10 mm wide, with resinous rim or rarely with wings to 0.4 mm wide, chartaceous, brown, sparsely minutely appressed-pubescent, reticulately nerved, usually resinous. Seeds obliquely transverse, oval in outline, 3--4.5 mm long, 2.2--3.5 mm wide; aril oblique, cupular, pale yellow.

Widespread in all mainland States except Vic. between 20° and 34° latitude, usually on shallow or gravelly soils on hills, often associated with A. aneura var. tenuis and/or A. aneura var. intermedia .

Often associated with A. aneura var. tenuis and/or A. aneura var. intermedia . The three varieties are closely related, intergrade and, on occasions, may be difficult to distinguish from each other.

Type of accepted name

Cudnaka, S.A., F.Mueller s.n .; holo: MEL; iso: MEL & ex herb. Sonder MEL.

Synonymy

Racospermum aneurum (F.Muell. ex Benth.) Pedley, Austrobaileya 2: 344 (1987). Type: as for accepted name.

Representative collections

W.A.: flats between Rhodes Ridge and Pamelia Hill, between Hamersley and Ophthalmia Ranges, M.E.Trudgen 440 (PERTH). N.T.: 15 miles [24 km] N of Alice Springs, D.J.Nelson 2232 & 2233 (BRI, NT). S.A.: Anginoora Ck, c. 30 km NE of Hawker on Chace Ra., D.N.Kraehenbuehl 6304 (AD). Qld: near ‘Buckingham Downs’, c. 50 km S of Dajarra, L.Pedley 5296 (BRI). N.S.W.: 8 km NE of Louth, L.Pedley 4706 (A, BRI, ILL, L, MEXU, MO, PERTH).

 

Acacia aneura var. conifera Randell, J. Adelaide Bot. Gard . 14: 122 (1992)

Tree to 8 m tall with horizontal branches giving general appearance of a pine tree. Branchlets with white-appressed and red-glandular hairs between resinous ribs. Phyllodes clustered along branchlets, two or three arising from single point, straight or curved, terete or flat, 3–5 (–7) cm long, 0.8–2 mm wide. Flowers with sepals 0.5–0.9 mm long; corolla 1.2–1.5 mm long; stamens 2.5–3 mm long. Pods flat, oblong, to 4.5 cm long, 6–10 mm wide, chartaceous, yellowish brown, sparsely appressed-pubescent, obscurely reticulately nerved, with resinous suture; aril cupular, pale yellow.

Widely distributed from near the W coast of W.A. through the N of S.A. and the S of N.T. to north-western Qld, with an isolated occurrence in SW Qld; there are some problematic records from the S of the species range in the Gairdner-Torrens and Northern Eyre Peninsula regions of S.A. The problem of identification of herbarium specimens of the taxon, considered below, has resulted in the uncertainty of its distribution in the S of its range. Usually associated with other variants of A. aneura on loamy and sandy soils in areas with low topography.

Herbarium specimens of A. aneura var. conifera are difficult to identify. Collectors’ notes on the plant’s habit are useful though they can be equivocal. Some collectors refer to a ‘Christmas tree’ form, which appears to be merely a growth form and not characteristic of A. aneura var. conifera . Chippendale NT4691 (15 miles SE of Anningie HS, N.T., 29 July 1958) cited in the protologue, has phyllodes less crowded than usual and to 8.5 cm long, beyond the range usually found in the variety: it is better referred to A. aneura var. tenuis . Maslin 2273a (also cited in the protologue) has a distinctly winged pod. It is described as a ‘shrub with cone-shaped habit’ and is A. paraneura .

Type of accepted name

c. 25 km NNW of Yuendumu, N.T., 25 Aug. 1981, P.K.Latz 8804 ; holo: PERTH; iso: CBG n.v. , DNA.

Representative collections

W.A.: Warburton Ra. area, 27 Dec. 1966, R.A.Gould s.n. (PERTH). N.T.: 4 km W of Hill of Leaders Mine, Kurundi Stn, P.K.Latz 9796 (NT, PERTH); Hermannsburg Road, 7 miles [11 km] W of Alice Springs, D.J.Nelson 2234 (BRI, K, NT). S.A.: Ernabella [Pukatja], L.B.Young comm. R.A.Black herb. no 252.039 (MEL); Tarcoola, E.H.Ising 1413 (AD). Qld: Barkly Downs Stn, S.T.Blake 17949 (BRI, K, MEL).

 

Acacia aneura var. macrocarpa Randell, J. Adelaide Bot. Gard. 14: 121 (1992)

Rounded shrub to 3 m tall. Branchlets with white-appressed and red-glandular hairs between resinous ribs. Phyllodes somewhat curved, terete, 6–9 cm long, 0.8–1 mm diam. Flowers with sepals 0.7–1 mm long; corolla 1.5–1.6 mm long; stamens 3.5 mm long. Pods oblong, to 10 cm long, 10–20 mm wide not winged, crustaceous, yellow at maturity, subglabrous, coarsely reticulately nerved, often with a distinct marginal rim. Seeds ± transverse, oval, c. 6mm long, 5 mm wide; aril cupular, pale yellow.

Scattered through the ‘mulga region’ of W.A., mainly towards the northern part, with one collection from the extreme NW of S.A., recorded from red sandy soil with spinifex ( Triodia spp.) and near drainage lines on heavier soils.

Differs from other varieties of A. aneura in its large pods and seeds, and long phyllodes but it shows some affinity with A. aneura var. pilbarana . A variant ( Maslin 2183 ) has flat phyllodes 2 mm wide and long narrow pods strongly longitudinally reticulately nerved. B.R.Randell ( op. cit . 122) suggested it might be derived from A. paraneura but is possibly an A. aneura var. macrocarpa ´ A. ramulosa hybrid.

Type of accepted name

Upper Rudall R., W.A., 13 Sept. 1971 , B.R.Maslin 2084 ; holo: PERTH; iso: BRI, CANB, K, MEL, NSW.

Representative collections

W.A.: upper Rudall R. area, B.R.Maslin 2216 (BRI, PERTH); 0.4 km S of Carrowina Ck, P.G.Wilson 956 & R.Rowe (NSW); 5 miles [8 km] W of Meekatharra, N.H.Speck 561 (BRI, CANB). S.A.: Mt Agnes, 25 Sept. 1955, S.A. Pastoral Board (AD).

 

Acacia aneura var. microcarpa Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Shrub or tree to 5 m tall. Branchlets with white-appressed and red-glandular hairs between resinous ribs. Phyllodes flat or subterete, thick, 4.5–8 (–9 ) cm long, 0.8–1.8 mm wide, usually slightly hooked at tip. Flowers with sepals 0.7–0.8 mm long; corolla 1.5–1.6 mm long; stamens c. 2.5 mm long. Pods flat, oblong, to 4 cm long, 5.5–8.5 mm wide, including wings, 0.6–1 mm wide, chartaceous, pale brown, glabrate when mature, with prominent longitudinally anastomosing nerves. Mature seeds not seen.

Extends from the Meekatharra–Mt Magnet region of W.A. with an isolated occurrence in the Pilbara region W of Newman, extending eastward with scattered occurrences in S.A. and southern N.T.; reported from red loamy and loamy-clay lateritic soils, sometimes on stream lines.

The variety is characterised by the wings of its pods which are uniform in width around the pods and wide in relation to the overall width of the pods. It is probably most closely related to A. aneura var. aneura , differing in its winged pods and its rather thicker phyllodes that are slightly hooked at the tips.

Type of accepted name

16 miles [26 km] SW of Nannine, Eremean Province, W.A., 8 Sept. 1957, N.H.Speck 726 ; holo: PERTH; iso: AD, CANB.

Representative collections

W.A.: Cue, K.F.Kenneally 52A (PERTH); 41.8 km S of Mt Magnet towards Paynes Find, B.R.Maslin 3573 (PERTH); 9 km S of Teutonic Bore Mine on Leonora–Agnew Road, S.J.Forbes 1546 (MEL, PERTH); 23 miles [37 km] N of Warburton Mission, A.S.George 8191 (PERTH). N.T.: c. 2.5 km NE of Mereenie Bore, Allambi Stn, W.A.Low 256 (NT). S.A.: Tarcoola Outstation, J.A.Mattner 49 (AD).

Acacia aneura var. tenuis Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Tree to 8 m tall. Branchlets brown, often with strongly resinous ribs, especially in northern part of the species’ range. Phyllodes straight or somewhat curved, terete or subterete, 3.5–11.5 cm long, 0.7–1.2 (–1.4) mm wide. Flowers with sepals 0.6–0.9 mm long; corolla 1.2–1.6 mm long; stamens 2.5–3 mm. Pods flat, oblong, to 3 cm long, 7–10 mm wide, with resinous rim or wings to c. 0.5 mm wide, chartaceous, yellowish brown, glabrous or with sparse appressed hairs, shining at or slightly before maturity, with only obscure reticulate narves. Seeds oblique to transverse, obloid, 4--5 mm long, c. 3 mm wide; aril cupular, pale yellow.

Widely ranging in all mainland States except Vic., though confined to the extreme W of N.S.W. It is especially common in the south of S.A. and in N.T., apparently absent from north-central S.A.

Most closely related to A. aneura var. aneura , differing in its terete or subterete phyllodes, conspicuously resinous branchlets and pods with valves shining at maturity.

Type of accepted name

Lorne Creek Desert, N.T., 20 Sept. 1947, C.J.Mulhearn 6713 ; holo: AD ex ADW.

Representative collections

W.A.: 11 km W of Wiluna on road to Meekatharra, B.R.Maslin 7074 (PERTH). N.T.: 53 miles [85 km] E of Harts Range Depot, G.Chippendale NT3167 (BRI, NT). S.A.: Mt Fitton, 30 Aug. 1972, B.Copley (AD, MEL, NSW). Qld: ‘Nerrigundah’ c. 60 km SW of Quilpie, L.Pedley 4204 (BRI). N.S.W.: 4.5 km S of Olive Downs HS, Sturt Natl Park, R.G.Coveny 13450 et al . (BRI, MEL, NSW).

 

Acacia aneura var. pilbarana Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Bushy rounded shrub to c. 4 m tall. Branchlets yellow-brown, white-appressed and red-glandular hairs between ribs, not strongly resinous. Phyllodes straight to strongly curved, terete or somewhat laterally flattened, (4–) 4.5–7.5 cm long, 0.6–1 (–1.2) mm diam. Flowers with sepals 0.7–1 mm long; corolla 1.3–1.6 mm long; stamens 2.5–3 mm long. Pods oblong, to 6 cm long, c. 7 mm wide, not winged, chartaceous, pale brown, glabrate, obscurely reticulately nerved, with marginal nerves conspicuous. Developed seeds not seen.

Common in the Pilbara region of W.A. where it is reported to occur on red loamy or clayey flats near watercourses with spinifex ( Triodia spp.).

The long pods and rather large seeds distinguish this variety from the others. Its wingless pods and ±terete phyllodes suggest an afinity with A. aneura var. tenuis .

Plants from farther S in the Meekathara–Mt Magnet region have shorter, stiffer phyllodes and there is little information on specimen labels on their ecology.

Type of accepted name

11 km NW of Newman on road to Rhodes Ridge , 8 July 1980, B.R.Maslin 4589 ; holo: BRI; iso: MEL, PERTH.

Representative collections

W.A.: Newman, K.Walker M.N.M. 215 (PERTH); 11.2 km W of Packsaddle Camp, Fortescue, L.A.S . Johnson 9312 & B.G.Briggs (BRI, NSW); c. 30 km E of Juna Downs HS, A.A.Mitchell PRP669 (BRI, PERTH); Boolardy Stn, Yalgoo, D.G . W [ ilcox ] M16 (PERTH).

 

Acacia aneura var. major Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Tree to 14 m tall. Branchlets densely pubescent, with hairs obscuring ribs when young. Phyllodes straight, flat, 2–6.5 (–8) cm long, (2.5–) 3–8 (–13 ) mm wide, densely pubescent when young. Flowers with sepals 0.6 mm long, rarely to 0.8 mm, free or occasionally united in a short tube; corolla 1–1.3 (–1.5 ) mm long; stamens c. 2.5 mm, rarely to 3 mm long. Pods oblong, to 5 cm long, 7–17 mm wide with wings 1–2 mm wide or wider, chartaceous, brown, densely pubescent when young, becoming glabrate, reticulately nerved. Seeds oblique to transverse, oval to oblong in outline, 3--4.5 mm long, 2.5--3.5 mm wide; aril obliquely cupular, pale yellow.

Occurs in all mainland States except Vic. In south-central Qld and central N.S.W. it is usually found on deep loamy soils often in situations where it receives run-on water from adjacent hills, often forming open forest and woodland communities alone or with Eucalyptus populnea , E. intertexta or other eucalypts. In more arid regions it occurs in lower, more open communities such as low woodlands and shrublands.

Acacia aneura var. major and A. aneura var. intermedia are closely related and one may prove merely an ecotype of the other. Both, however, are clearly distinguished from A. aneura var. aneura by their wide phyllodes and winged pods. Plants from the vicinity of the eastern end of the Hamersley Ra., W.A. (e.g. B.R.Maslin 4620 & 7235 , S.van Leeuwen 838 ) are placed here with doubt. Their phyllodes (6.5–8 cm) and spikes (to 4 cm) are both longer than is normal in A. aneura var. major . B.R.Randell (J. Adelaide Bot. Gard . 14: 125, 1992) referred material of A. aneura var. major to A. ayersiana var. latifolia (see, however, A. ayersiana ).

Type of accepted name

33 miles [53 km] from Cunnamulla on Bollon road, 8 Sept. 1967, L.Pedley 2420 ; holo: BRI; iso: AD, MEL, MEXU, MO, NT, PR.

Representative collections

W.A.: 31 km E of Newman on road to Port Hedland, B.R.Maslin 7235 (BRI, PERTH). N.T.: 27 miles [43 km] N of L. Amadeus, G.Chippendale NT6345 (BRI, MEL, NT). S.A.: 21 km W of Mt Christie, F.A.Mowling 66 (AD). Qld: Charleville, C.E.Hubbard 8633 (BRI, K). N.S.W.: 7 miles [11 km] S of Cobar, E.J.McBarron 16851 (MEL, NSW).

 

Acacia aneura var. intermedia Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Shrub or tree to 5 m tall. Branchlets pubescent but hairs not obscuring ribs. Phyllodes straight or somewhat curved, flat, 3–7 (–9) cm long, 2.5–4.5 (–6) mm wide, pubescent when young. Flowers with sepals 0.5–0.8 mm long; corolla 1.2–1.6 mm long; stamens 2.2–3 mm long. Pods oblong, usually to 3.5 cm long, 8–12 mm wide, including wings usually at least 1 mm wide, chartaceous, brown, sparsely appressed-pubescent. Seeds oblique, 4--6 mm long, 2.5--3 mm wide, obloid; aril obliquely cupular, pale yellow.

Occurs throughout the range of the species but absent or uncommon in N.T. north of about 22° latitude, on shallow or gravelly loams on hillsides (at least in the east of its range). Where it occurs with A. aneura var. major it is often found on shallower less moisture-retentive soils (‘hard mulga soils’) sometimes with Corymbia tumescens . Occurrences near L. Buchanan, Qld and a little W of Scone, N.S.W. represent the eastern extremity of the range of ‘mulga’.

Closely related to A. aneura var. major which has similar small flowers and widely winged pods. It differs in its less densely pubescent branchlets, usually narrower phyllodes and pods with narrower wings. Some specimens from W.A. have grey-resinous branchlets characteristic of A. minyura and some the chocolate-brown growing points characteristic of A. aneura var. fuliginea , perhaps indicating intergrades with these taxa.

Type of accepted name

Hiraji Bore, Napperby [Laramba], 100 miles [160 km] NW of Alice Springs, N.T., 27 Jan. 1950, S.L.Everist 4226 ; holo: BRI.

Representative collections

W.A.: ‘Four Mile Hill’, c. 4 miles [6 km] NE of ‘Kanowa’, B.R.Maslin 1875 (PERTH). N.T.: 47.6 km E of Curtin Springs, B.G.Thomson 2278 (DNA, NT). S.A.: c. 10 km W of Italowie Gorge, c. 30 km E of Copley, T.R.N.Lothian 2557 (AD). Qld: 25 km W of Bollon, T. & J.Whaite 3814 (CBG, MEL, NSW). N.S.W.: foothills of Gunderbooka Ra., 25 miles [56 km] by road S of Bourke, E.F.Constable 4549 (MEL, NSW).

 

Acacia aneura var. fuliginea Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Tree to 7 m tall. Branchlets with white appressed and red-glandular hairs between resinous ribs; new growth conspicuously dark chocolate brown with dense glandular hairs persisting on developing phyllodes. Phyllodes flat, ±straight, 3.5–7.5 (–9) cm long, 3–6 mm wide, 6–20 (–30) times longer than wide, resinous, the marginal nerve sometimes prominent. Flowers with sepals 0.6–1.1 mm long, free; corolla stout, c. 2 mm long; stamens c. 3.5 mm long. Pods (not seen mature) to 4 cm long, 8–9 mm wide, with resinous marginal nerves, not winged, coarsely reticulately veined, sparsely pubescent, probably glabrescent.

Occurs in the extreme west of the range of A. aneura between about 25° and 30° latitude, on reddish clayey loams and occasionally sand.

Closely related to A. aneura var. argentea , differing in its often narrower phyllodes, larger flowers and especially by its dark chocolate brown young foliage with dense red-glandular trichomes persisting until the phyllodes are well-developed.

Type of accepted name

2 km W of Mid Shiner Well, Milly Milly Stn, W.A., 28 Apr. 1956, R.J.Cranfield 5383 ; holo: PERTH.

Representative collections

W.A.: ‘Belele’, Meekatharra, A.W.Humphries M31 (PERTH) & May 1974, M.Kerkhoff s.n. (PERTH); L. Austin, 31 May 1966, B.M.Allender s.n. (PERTH); Lennonville, c. 10 km N of Mt Magnet, B.R.Maslin 3585 (PERTH); 48 miles [77 km] E of Mt Magnet, J.W.Green 1625 (PERTH).

 

Acacia aneura var. argentea Pedley (ms), to be published in Appendix to Fl. Australia vol. 11 (2001)

Tree to 7 m tall, with silvery or silver-grey foliage. Branchlets densely appressed-pubescent between ribs. Phyllodes flat, ± straight, 3–5.5 (–6.5) cm long. 5–8 mm wide, 3.5–9 times longer than wide, rarely longer; nerves sometimes capped with grey resin and marginal nerve occasionally prominent (as in A. ayersiana ). Flowers with sepals 0.8–1.1 mm long, free or occasionally united in a short tube; corolla 1.4–1.6 mm long, appressed pubescent near lobe tops, sometimes with only a few hairs; stamens 2.5– 3 mm long. Pods to 3.5 cm long, 9–12 mm wide, with resinous rim, without wings, chartaceous, brown, coarsely reticulately nerved, minutely appressed pubescent Mature seeds not seen.

Occurs towards the western limit of the range of A. aneura , apparently most common in the Mt Magnet–Leonora region, sometimes forming pure stands on sandy or clayey loams.

Closely related to A. aneura var. fuliginea and intergrades with it, but often has wider phyllodes with nerves capped with grey resin, smaller flowers and, above all, lacks the conspicuously dark chocolate brown, new growth. It also resembles A. aneura var. major , most common in eastern Australia, but is distinguished mainly by its wingless pods.

Type of accepted name

Near Edah, W.A., Mar. 1938, A.Stewart 197 ; holo: PERTH.

Representative collections

W.A.: 10 miles [16 km] E of Paynesville, J.W.Green 1626 (PERTH); 8 km ENE of Yuinmery HS, J.Dell JD 46 (PERTH); Carnarvon Ra. and vicinity, A.A.Burbidge 4 (PERTH); south of Menzies, L.Diels 5122 (PERTH ex B).

(LP)

 

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