Cyperus difformis, L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1980, Flora Europaea. Volume 5. Alismataceae to Orchidaceae (Monocotyledones), Cambridge: Cambridge University Press : 286-287

12. C. difformis L. , Cent. Pl. 2: 6 (1756).

Caespitose annual; stems 20-75 cm. Leaves 2-7 mm wide, shorter than the stems. Bracts 2-4, exceeding the inflorescence. Inflorescence a simple or compound umbel of dense heads; rays 3-8, up to 5 cm. Spikelets 2 -8 xc. 1mm, linear, with 10-40 flowers, patent. Rhachilla not winged. Glumes 0-5-0-7 x 0-5 mm, obovate or suborbicular, obtuse, reddish or brownish with paler centre. Stamen 1 (2-3). Nut subequalling the glumes, pale yellow or yellowish-green. 5. Europe. Al Bu Co Ga Gr Hs lt Ju Lu Rm Rs (W) SiTu [Az.]

Widespread as a weed in rice-fields; its European distribution as a native is for this reason uncertain.