Family

Fabaceae

Distribution

Restricted to the upper catchments of eastern tributaries of Nourlangie Ck, Kakadu Natl Park, N.T.

Description

Tree or large shrub to 5 m high, branches sometimes sprawling. Branchlets dark red, angular, glabrous. Phyllodes narrow, lanceolate-falcate, widest above middle, 7–13 cm long, 4–8 mm wide, glabrous; apex with callus point, sometimes oblique; longitudinal nerves 8–14, widely spaced, (2–) 3–5 per mm, with an occasional anastomose; gland basal; pulvinus 1.5–2.5 mm long. Spikes paired in upper axils, interrupted, 3.5–4.5 cm long, yellow; peduncles 1–2 mm long, glabrous. Flowers 4-merous; calyx 0.5 mm long, shortly lobed, glabrous except for a few hairs on lobes; corolla lobed to level of calyx, c. 1.5 mm long, strongly reflexed; stamens c. 2.5 mm long; ovary glabrous. Pods glabrous, linear, straight or slightly curved, to 9 cm long, 2–3 mm wide, reticulately nerved, with thickened margins, raised over seeds. Seeds longitudinal, obloid, 2–2.5 mm long, 1.5–1.7 mm wide; aril small, cupular, yellow.

Phenology

Flowers collected Jan. & Apr.; fruits collected Mar. & Apr.

Habitat

Found in sand and gravel on gentle slopes and in crevices on sandstone pavements.

Specimens

N.T.: Radon Ck, Mt Brockman, C.R.Dunlop 4679 (BRI, DNA); Deaf Adder Gorge, R.E.Fox 2433 (BRI, DNA); Arnhem Land Plateau, upper catchment of Magela Ck, I.D.Cowie 5616 & K.Brennan (BRI, DNA, PERTH); Mt Brockman Outlier, 15 km SE of Jabiru, R.W.Johnson 4797 (BRI, CANB, DNA, MEL, NSW).

Notes

Related to A. diastemata. These two species may have affinities with 4-merous, juliflorous taxa of the ‘A. longifolia group’ from SE Australia; see B.R.Maslin, Nuytsia 23: 557–558 (2013), for discussion. In general appearance A. scopulorum resembles A. spirorbis and A. leptostachya, and has been distributed from DNA as the latter, but differs from both in its small 4-merous flowers.

FOA Reference

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

Author

L.Pedley

Minor edits by B.R.Maslin & J.Rogers