WATTLE

Acacias of Australia

Print Fact Sheet

Acacia williamsonii Court

Common Name

Whirrakee Wattle

Family

Fabaceae

Distribution

Occurs from Inglewood E to Rushworth, Vic.; it is especially common in the Bendigo ‘Whipstick’. The few specimens from N.S.W. are assumed to represent introductions (e.g. intersection Hynes Land and South Coree Rd, 10 Oct. 1995, M.F.Porteners s.n. & E.M.Ashby (CANB, NSW, PERTH).

Description

Bushy shrub to 2 m high. Branchlets glabrous. Phyllodes narrowly linear, normally shallowly incurved, 4–9 cm long, 1.5–3 (–4) mm wide, narrowed at base, not rigid, glaucous and inclined to ascending, often green or subglaucous and patent at ends of flowering branchlets, glabrous; midrib not prominent; lateral nerves absent; gland 7–27 mm above pulvinus, often absent. Inflorescences racemose; racemes usually 1–3 cm long, glabrous, normally drying dark reddish brown; peduncles 2–3 mm long, rather stout, glabrous, sometimes appressed-puberulous, drying dark reddish brown to blackish; heads globular, subdensely 15–20-flowered, bright golden; bracteole laminae ±circular, dark brown to blackish, white-fimbriolate. Flowers 5-merous; sepals c. 5/6-united. Pods normally ±moniliform, to 9 cm long, 3–3.5 mm wide, firmly chartaceous to somewhat crustaceous, black, glabrous. Seeds longitudinal, oblong to elliptic, 3.5–4 mm long, somewhat shiny, black; aril clavate.

Habitat

In the Bendigo ‘Whipstick’, it grows in stony gravel or clay loam, in open Eucalyptus forest and mallee open scrub.

Specimens

Vic.: Bendigo Whipstick, c. 12 km due N of Bendigo township, B.R.Maslin 5848 (PERTH); Whipstick, 0.8 km N of Eaglehawk Rifle Ra., 23 Aug. 1959, W.Perry (MEL); Inglewood, J.Stuwe 825 (MEL).

Notes

Closely allied to the less floriferous A. hakeoides which differs especially in its wider, green phyllodes, usually 20–27-flowered heads and 4–6 mm wide pods with dull seeds 5–7 mm long. Its flowers and bracteoles are similar to those of A. hamiltoniana.

Putative hybrids between A. pycnantha and A. williamsonii occur in the Bendigo ‘Whipstick’, and superficially resemble A. hakeoides.

A variant from near Rushworth, c. 50 km E of Bendigo (e.g. 4 Sept. 1974, J.H.Willis, MEL) differs especially in its very long racemes (to 9 cm long), and its linear pods (few seen) which are only slightly constricted between the seeds.

Very decorative shrubs with a neat rounded or obconic shape and a profusion of bright golden inflorescences in the upper axils; admirably suited as an ornamental.

FOA Reference

Data derived from Flora of Australia Volumes 11A (2001), 11B (2001) and 12 (1998), products of ABRS, ©Commonwealth of Australia

Author

Minor edits by B.R.Maslin & J.Rogers

B.R.Maslin