Cyperus rotundus L.

Etymology	Genus	After the Greek common name of the sedge, "kuperos"
	Species	Round or fat; perhaps referring to its tubers
Family		Cyperaceae
Synonyms		Chlorocyperus rotundus (L.) Palla, Pycreus rotundus (L.) Hayek, Cyperus maritimus Bojer
Common Names		Nut Grass, Coco Grass, Purple Nut Sedge
Status		Native: Least Concern
Form		Herb
Native Distribution		Eurasia

Diagnostics

Cyperus rotundus is a very common sedge found in lawns and scrublands. The flowering stem is triangular while its leaves which wrapped around the stem at the base are grooved at the mid-vein. The inflorescence is most distinctive, where the linear spikelets are reddish-brown in colour.

Interesting Facts

The Nut Grass is so known because it has a swollen underground tuber, resembling the shape of a peanut (note that the peanut itself is a fruit, not a tuber). It is regarded as one of the world's worst weeds in agricultural areas (Holm et al., 1977).

References

Holm LG, Plucknett DL, Pancho JV & Herberger JP. (1977) The world's worst weeds: distribution and biology. East-West Center, University Press of Hawaii. 609 pp.