Family

Fabaceae

Distribution

Known only from near Lake King (Lake King is c. 105 km due E of Lake Grace) NE to the Bremer Ra. (c. 105 km WSW of Norseman), also near Ravensthorpe and near Sheoak Hill (c. 80 km due NE of Esperance), south-western W.A.

Description

Spreading shrub 0.15–0.4 m high. Branches striate-ribbed, white-waxy between ribs, hirtellous. Branchlets short, straight, rigid, patent to inclined, spinose. Phyllodes obliquely ovate to elliptic or obovate, 3–6 mm long, 1.5–3.5 mm wide, narrowed to a short acute obliquely subrecurved apiculum, hirtellous, with scarcely prominent midrib, sometimes imperfectly 2-nerved; lateral nerves few or absent. Inflorescences rudimentary 1-headed racemes with axes < 0.5 mm long; peduncles 2.5–4 mm long, glabrous, recurved in fruit; basal bracts brown; heads globular, 9–11-flowered, light golden. Flowers 5-merous; sepals irregularly united for more than half their length, 1/4–1/3 length of petals; petals glabrous, nerveless. Pods rounded over seeds and variably constricted between them, curved, to 3 cm long, 4–4.5 mm wide, firmly chartaceous to thinly coriaceous, dark coloured, glabrous; margins inrolled on one side. Seeds longitudinal, widely ovate, 3 mm long, shiny, dark brown except for yellow-brown tissue enveloping areole and extending to hilum; aril c. 3/4 seed length.

Habitat

Grows in clay, rocky loam or sand, in transition between heath and shrub mallee.

Specimens

W.A.: Frank Hann Natl Park, D.Monk 054 (PERTH); 4.8 km SE of Ravensthorpe, K.Newbey 1615 (PERTH); 20 km WSW of Mt Glasse, Bremer Ra., K.Newbey 5566 (PERTH).

Notes

Inflorescence and flower characters suggest that A. improcera is related to A. bidentata and its allies, differing however in its phyllode shape (phyllodes of A. bidentata are inequilaterally obovate to obtriangular-obdeltate). Other useful distinguishing characters are its striate, spinose, white-waxy branchlets, light golden, few-flowered heads, curved pods and bicoloured seeds. Acacia erinacea is similar to A. improcera, especially in its spinose branchlets and phyllode shape and size, but is distinguished most readily by its glabrous branchlets and phyllodes, 12–22-flowered heads and pod morphology. Although A. improcera superficially resembles A. brachyclada in phyllode shape and size the two are not closely related.

FOA Reference

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

Author

B.R.Maslin

Minor edits by J.Rogers