WATTLE

Acacias of Australia

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Acacia nicholsonensis Cuff

Family

Fabaceae

Distribution

Known only from the Waanyi/Garawa Aboriginal Land Trust and adjacent Benmarra Stn, N.T.

Description

Obconic shrub or small tree 3–6 m tall. Bark ‘Minni Ritchi’, red to red-brown. Branchlets appressed hairy. Phyllodes linear to narrowly linear, (85–)100–150(–185) mm long, 1.1–1.5 mm wide, flat (narrowly transversely elliptic to sub-terete or flat when young), normally straight to shallowly incurved, ascending to erect, not rigid, with short, appressed hairs between nerves and longer, ascending hairs on nerves and margins, pale green to grey-green, apices terminated by a short, hard, innocuous point; longitudinal nerves normally 5–8, conspicuous, sub-distant, not anastomosing. Inflorescences simple; spikes 15–25 mm long; peduncles 3–9 mm long, with dense, appressed, yellow-gold hairs. Flowers 5-merous; calyx gamosepalous, dissected for c. 1/3-1/4 its length. Pods linear to narrowly oblong, 40–110 mm long, 2.4–4 mm wide, coriaceous to sub-woody, straight to moderately curved, flat, resinous (especially when young), densely lanate by golden brown hairs. Seeds longitudinal, ovate to elliptic, 3–4.5 mm long, pleurogram prominent and encircling raised areole, arillate.

Phenology

Phenology uncertain but flowers seemingly June.–Sept., possibly related to quality of preceding wet season.

Habitat

it occurs in fine red-brown loamy sands on lower levees and banks of the upper reaches of the South Nicholson R. Estimates indicate that less than 12 500 mature plants exist in nature, but further survey is needed.

Notes

Perhaps most closely related to A. cyperophylla which differs in having is most readily readily recognized by its glabrous, normally terete phyllodes and glabrous pods. Superficially similar to A. fauntleroyi and A. oncinophylla from SW W.A., but the relationship is not likely to be close. See Cuff, Nuytsia 28: 156 (2017) for further discussion of relationships.

FOA Reference

Flora of Australia Project

Author

B.R. Maslin