Slender, tufted perennial, with slender, short rhizome. Culms very slender, acutely trigonous, usually smooth, (10–)15–40 cm high, 0.3–0.7 mm diam. Leaves thin, flat or folded, slightly keeled, the keel and margins scabrous above the middle, usually shorter than culms, (0.6–)0.8–2 mm wide. Inflorescence ± loose, 1.5–3 cm long including male portion 6–11 mm long; female glumes deciduous, acute, straw-coloured, membranous, faintly several-nerved, 4–5 mm long; stamens 3; utricles trigonous, ovoid to ellipsoid, 4.5–5.5 mm long, 1.5–1.8 mm diam., gradually narrowed to base, with 2(–4) prominent nerves, smooth and shining between nerves, obliquely spreading at maturity, about as long as glumes, yellow-brown; rachilla produced far beyond mouth of utricle, strongly hooked at the top, up to ca. twice as long as the utricle. Nut ellipsoid, dark grey-brown, glistening, rather smooth, minutely isodiametrically reticulate, c. 3 mm long, c. 1.5 mm diam. Flowers summer.
EGU, HSF, HNF, Strz, VAlp. Also NSW, ACT, Tas. In alpine areas, commonly beside rocks.
Carex austroflaccida was published as a replacement name for Uncinia flaccida Blake, in the belief that the name flaccida was unavailable in Carex because of the earlier combination Carex flaccida Sw. However, Swartz’s name is invalid, and therefore the epithet flaccida is currently available in Carex. The new combination was recently published by Wilson (2020).
