Plants perennial. Culms to 250 cm; nodes
often swollen. Basal sheaths glabrous, smooth, purplish-red; ligules
3-6 mm, acute; blades to 100 cm long, 3-16 mm wide, surfaces smooth or
scabrous. Inflorescences to 100 cm, linear, interrupted; rames
10-17 mm; internodes and pedicels pilose on the margins, glabrous
dorsally. Sessile spikelets of heterogamous pairs 3-4.5(6) mm; lower
glumes with narrowly winged keels; upper lemmas unawned or awned,
awns 6-10 mm. 2n = 20, 40, 60.
Cymbopogon nardus has been cultivated in the United States,but the variety
involved is not known. Cymbopogon nardus (L.) Rendle var. nardus,
which is native to Sri Lanka, is the common citronella grass. It differs from
C. nardus var. confertiflorus (Steud.) Stapf ex
Bor, which is native to both Indian and Sri Lanka, in having
unawned spikelets and 2n = 20, rather than awned spikelets and 2n
= 40, 60. Both varieties have been widely introduced beyond their native range.