any of the 40 species of the genus Cymbopogon (family Poaceae), aromatic, oilcontaining grasses cultivated in the tropics of Asia and Africa and introduced into tropical America. Most species are densely tufted, with long, narrow, flexible leaves.

Lemon-oil grass or sweet rush (Cymbopogon citratus) contains citral, obtained by steam distillation of the leaves and used in scented cosmetics, food flavouring, and medicine. Citronella grass (C. nardus) contains geraniol ( citronella oil), used in cosmetics and insect repellents.