Common Name

Norm’s Whorled Wattle

Family

Fabaceae

Distribution

Occurs in the E Kimberley region, SE of Kununurra, in northern W.A.

Description

Spindly, single-stemmed, sparingly branched, erect shrub 1–2 m tall. Branchlets densely pubescent with short, patent or slightly retrorse hairs. Stipules setaceous to linear-triangular, mostly 1.5–2.5 mm long. Phyllodes 14–20 per whorl, 4–10 mm long, 0.4–0.7 mm wide, apices terminated by a setose point 1–1.5 mm long, ascending to erect to patent, mostly flat, straight to shallowly recurved, pubescent by fine, very short hairs to c. 0.1 mm long; longitudinal nerves 1 or 3 on lower surface. Peduncles 10–17 mm long, pubescent with hairs similar branchlets except less dense. Heads 35–45-flowered; bracteoles narrowly lanceolate, 2.5–3.5 mm long, slightly exserted in buds, glabrous, long-acuminate to caudate. Flowers 5-merous; calyx 1/3–2/5 length of corolla, shortly dissected into 5–10, linear to narrowly triangular lobes; petals 5, striate but sometimes obscurely so, glabrous or sparsely short-hairy at apices. Pods sub-sessile, narrowly oblong, 25–50 mm long, 6–7 mm wide, flat but raised over seeds along midline; marginal nerve thickened. Seeds longitudinal, irregularly obloid to cubic or widely ellipsoid, 4–4.5 mm long, black, slightly shiny.

Phenology

Paucity of collections prevents a comprehensive assessment of phenology but seemingly flowers from late ‘wet season’ at the end of Jan., continuing to at least early Apr.; mature pods often occur with flowers.

Habitat

Known from only a single sandstone range.

Notes

Closely related to A. anasilla which is distinguished by its denser and more conspicuous branchlet indumentum, generally longer peduncles and shorter calyx, and phyllodes with longer apical setae and a more conspicuous indumentum of longer hairs. Also related to A. perryi and A. prolata which have ±nerveless phyllodes; A. perryi is further distinguished by its non-setose phyllode mucro, and A. prolata by its normally free sepals that are c. ½ the length of the petals. See B.R.Maslin, Nuytsia 24: 190-191 (2014) for further discussion.

Conservation

Acacia mackenziei is listed as Priority One under Department of Parks and Wildlife Conservation Codes for Western Australian Flora.

FOA Reference

Flora of Australia Project

Author

B.R. Maslin