Citation: G. Don, Gen.Syst. 2:403 (1832).

Derivation: rigens (Latin)stiff or rigid, referring to the stiff unbending needle-like phyllodes.

Synonymy: Racosperma rigens (A. Cunn. ex G.Don)Pedley, Austrobaileya 2:355 (1987).

, Acacia chordophylla

Common name: Nealie, Needle bush wattle

Description:
Erect, spreading, much-branched, glabrous or minutely hairy shrubs 2-3 m high, sometimes developing a small tree-like form and attaining heights of 4-6 m; branchlets striate with yellow ribs; bark greyish-green.

Phyllodes linear, 3-13 cm long, 1-2.5 mm broad, straight or curved, ascending, terete or compressed, striate, rigid, tough, not snapping easily, young phyllodes pubescent, glabrous or slightly pubescent when mature, veins longitudinal, c. 15, yellowish, some appearing more prominent than others, apex ending in a short straight or curved innocuous point; glands basal.

Inflorescences simple and axillary, solitary or twin, sometimes in clusters up to 4 heads; flower-heads globular, mid-yellow, 20-30-flowered; peduncles hoary, 3-6 mm long; flowers 5-merous.

Legumes linear, 5-7 cm long, 2-3 mm broad, curved and loosely coiled, hoary, constricted between seeds. Seeds longitudinal in legume, ellipsoid; funicle filiform, with several folds below the seeds and thickened into a conical aril.

Distribution:  Eyre Peninsula, Yorke Peninsula, Northern and Southern Lofty regions, the Flinders Ranges, Murray and South-Eastern (upper part) regions; usually in open scrub, associated with Eucalyptus socialis and E. gracilis or E. incrassata and Melaleuca uncinata. Soils: mainly sandy alkaline yellow duplex, dark or grey-brown calcareous loamy earths, or brown calcareous earths. Rainfall 200-250 mm. Also Qld., N.S.W. and Vic. S.Aust.: NW, NU, GT, FR, EP, NL, MU, YP, SL, SE. Flowering time: July — December.

SA Distribution Map based on current data relating to specimens held in the State Herbarium of South Australia

Biology: No text

Related taxa: Often confused with Acacia havilandii which differs in having brittle phyllodes with more numerous fine inconspicuous veins. Acacia gilesiana is similar as to phyllodes but has flower-heads in racemes.

Taxonomic notes: The only species of mistletoe recorded on A. rigens has been a single collection of Amyema quandang, grey-leaved mistletoe.

A. rigens is a plant food for the larvae of the butterfly Nacaduba biocellata, Fisher (1978).

Cultivation: A very useful shrub for planting in dry inland areas. Moderate to fast growth rate.

Author: Not yet available

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