Erect rhizomatous shrub to 1.2 m high, ±glabrous, new growth often sparsely hairy; branches flattened and winged, ultimate branches of cladodes 2–10 mm wide, recess at nodes absent or very shallow, greyish green (green when young). Leaves reduced to scales 2–4 mm long, up to 1 mm wide from midrib to margin, venation obscure. Flowers usually solitary, 7–10 mm long; pedicels c. 2 mm long; bracts several, conspicuous, reddish-brown, distichous, 2–3 mm long, persistent; bracteoles inserted near base, caducous; calyx 4–5 mm long, glabrous; standard ± equal in length to other petals, deep yellow, sometimes suffused with red on inner surface; ovary shortly stipitate, glabrous, 4–6-ovuled. Mature pods very rarely produced. All known occurrences are clonal. Flowers Oct.