Acacias of Australia

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Acacia undulifolia A.Cunn. ex G.Lodd.




Scattered across the higher Blue Mtns of N.S.W., from the vicinity of Mt Monundilla in the north to the Megalong Valley in the south and from the Coxs R. area eastwards into the Watagan Ra. and the Bucketty area.


Open shrub to 2 (–3) m high, with few primary branches; branches erect to inclined, distally upwardly curved to straight. Branchlets ridged or angled becoming somewhat terete, reddish brown or sometimes green, smooth to sparsely subtuberculate, moderately to sparsely hairy. Phyllodes with lamina rotated to 30º–60º from plane of branchlet or rarely vertical, slightly asymmetric, flat or sometimes convex, broadly ovate to sometimes broadly elliptic, very occasionally orbicular, (13–) 17–25 (–35) mm long, (10–) 12–16 (–22) mm wide, l:w = 1.1–2, green to grey-green or blue-green, sparsely hairy or glabrous, except usually with a few hairs on margin and midrib, particularly towards base; base obliquely obtuse or sometimes acute to truncate; margin undulate; apex acuminate to acute or obtuse and mucronate; gland usually inserted up to 1/8 length of margin from base, occasionally basal. Inflorescences with peduncles inclined upwards, 6–16 mm long, hairy; heads 8–9 mm diam., usually 20–26 (–30)-flowered, pale yellow. Corolla lobes glabrous or hairy; hairs long. Pods narrowly oblong to oblong, straight, 40–80 mm long, 16–24 mm wide, firmly coriaceous, subglossy, blackish; margin barely constricted between seeds.


Mostly on stony sandy loams derived from sandstones.


N.S.W.: 400 m NE of corner of Backmans Creek road and Great Western Hwy, Hartley, D.Benson 1817 & D.Keith (NSW); 6 km NE of Mt Monundilla, T.M.Tame 491 & T.Williams (NSW); near Flat Rock, Mt Face, W of Wollombi, T.M.Tame 1836 (NSW); Apple Tree Ck, T.M.Tame 2689 (NSW); Bucketty, T.M.Tame 3853 (NSW).


Branchlet hairs are slightly inclined to patent, straight or wavy, 0.2–0.5 mm long, and white or hyaline. The inflorescence hairs are patent and hyaline.

In the east of the distributional range, particularly in the Bucketty to Wollemi Ck area, the plants generally have larger phyllodes which are more sparsely hairy (phyllodes 17– 25 (–35) mm long) than the more western and northern populations (phyllodes 10–18 (–21) mm long). In the north of its range, A. undulifolia is parapatric with A. piligera, and sympatric with it in the Howes Mtn to Bulga area. The phyllodes of A. undulifolia are nearly always ovate and the heads are pale yellow, whereas the phyllodes of A. piligera are broadly elliptic to obovate and the heads are yellow to dark yellow.

FOA Reference

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


B.J.Conn, T.M.Tame