Cyperus rotundus L.
A rhizomatose, tufted perennial; rhizome with ovate tubers. Stems solitary, triangular, 10 to 50 cm long. Leaves linear, flat, 2 to 5 mm wide. Inflorescence umbel-like, with 3 to 9 unequal rays, and with 3 to 7 very unequal bracts, with the outer ones longer than the inflorescence. Spikelets 8 to 20 mm long; linear to oblong; with up to 35 florets. Glumes dark brown or reddish, 3 to 4 mm long; ovate.
Local: Common in Gibraltar, mainly at North Front Cemetery and Alameda Gardens, but also as a weed in cultivated plots around Gibraltar.
Global: Found throughout Mediterranean Europe, west Asia and tropical parts of Africa and America.
Flowers from (April) May, June, July, August to September (October).
Grows in damp, sandy places, often near the sea.