Yellow Flatsedge

Annual, or possibly caespitose perennial, 5-60 cm. Stem 0.5-1.5 mm diam., trigonous, obtusely trigonous below, smooth. Leaves shorter than stem; sheaths 20-50(100) mm, reddish-brown or brown, mouth margin slightly concave; blades up to 10 (-20) cm, (0.5-)1-2 mm wide, keeled or flat, grey-green, margins slightly involute, margins and midvein below scabrous, especially towards the acute apex. Inflorescence a globose cluster of spikes or a small anthelodium, primary branches up to 40 mm, cluster of spikes with c. 100 spikes, 15-30 mm diam.; bracts 2-3 foliose, up to 10(-20) cm; tubular prophyll brown. Spikes 5-15 x c. 2.5 mm, compressed, with up to 40 glumes; glume-like prophyll basally swollen; rachis quadrangular, almost straight, angles sharp, not winged, internodes c. 0.5 mm; glumes 2-2.5 mm, cymbiform, blunt mucronate, sides yellow-brown, margins scarious. Stamens 2. Nut 1-1.2 mm, globose or ellipsoid, stipitate, compressed, from yellow-brown to dark-brown, shiny, reticulate with areole twice as long as wide or more, lower ends of areole at same horizontal level, sometimes white protruding.

Distribution: Madeira, S and C Europe (from Portugal to Denmark and the Baltic), S and C Europ. Russia to Caucasus, all Africa (except NE parts and Madagascar), Lebanon, rare in Syria and Iraq, Turkey, Uzbekistan, Tadjikistan, Kazakhstan, from N Iran to Pakistan and Kashmir; introduced to E Australia; N and S America; the record from Vietnam is erroneous (Kern in Blumea 10: 641. 1960).

Fl. Per.: August - September.

Rice fields, moist alluvial meadows.

Cyperus flavescens L., Sp. Pl. 1: 46. 1753; C.B.Clarke, l.c. 589; R.R.Stewart, l.c. 89; Nyárády, Fl. Rep. Soc. România 11: Pl. 120, 3. 1966. K.M. Matthew, Fl. Tamilnadu Carnatic 4: Pl. 692. 1988.