Cyperus rotundus
L. NutgrassRhizomatous perennial with slender rhizomes forming ovoid to ellipsoid, woody tubers 0.5–1 cm diam., which annually shed their grey-brown, fibrous coat. Culms triquetrous, smooth, 15–30(–60) cm high, 1–2 mm diam. Leaves not septate-nodulose, shorter than culms, 2–6 mm wide. Inflorescence mostly simple with 3–9 primary branches to 10 cm long; spikes short, ovoid, to 2.5 cm long, to 3 cm diam.; involucral bracts leaf-like, 2–4 not or slightly exceeding inflorescence. Spikelets flattened, 3–10 per spike, 10–40-flowered, 10–25(–30) mm long, 1.5–2.5 mm wide in side view; rachilla broadly winged, persistent; glumes obtuse, with sides 1–3-nerved, 3–3.5 mm long; stamens 3; style 3-fid. Nut rarely maturing in Victoria, trigonous, narrowly obovoid to ellipsoid, dark grey-brown, less than one-half as long as glume, c. 1.5 mm long, c. 0.5 mm diam. Flowers spring–summer.
MuM, Wim, VVP, VRiv, MSB, RobP, MuF, GipP, CVU, NIS. Naturalised in all mainland States. Native to Africa, Asia. A locally common and troublesome weed in disturbed situations, mostly around habitation but occasionally infesting crops.
Wilson, K.L. (1994). Cyperaceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons, pp. 238–356. Inkata Press, Melbourne.
Spinning
