Cymbopogon mekongensis A. Camus

Cymbopogon mekongensis is very close to C. caesius (Nees ex Hooker & Arnott) Stapf, which occurs down the eastern side of Africa through Arabia to Pakistan and in S India and Sri Lanka. Cymbopogon caesius differs by the markedly swollen, barrel-shaped pedicel of the homogamous spikelet pair, which is fused to the swollen adjacent internode. It also tends to have greenish yellow rather than reddish inflorescences.

Perennial. Culms densely tufted, wiry, 30–80 cm tall. Leaf sheaths glabrous; leaf blades linear, glaucous, 10–25 × 0.2–0.6 cm, glabrous, base narrowly rounded, apex filiform; ligule 0.7–3 mm. Spathate compound panicle narrow, 10–30 cm, spathes densely clustered; spatheoles reddish brown, 1.4–2 cm; racemes reddish brown, 0.7–1.4 cm; rachis internodes and pedicels ca. 1.5 mm, ciliate on margins; pedicel of homogamous pair linear to columnar, not or only very slightly swollen, not fused to internode. Sessile spikelet oblanceolate, 3–4.3 mm; lower glume flat, deeply grooved below middle (appearing as a line or keel on inside), keels broadly winged above middle, veinless or obscurely 2-veined between keels; upper lemma deeply 2-lobed; awn 1.1–1.5 cm. Pedicelled spikelet 3–4 mm. Fl. and fr. Jul–Sep.

Roadsides, hill slopes. Guangdong, Guangxi, Guizhou, Hainan, Hunan, Sichuan, Yunnan, Zhejiang [Laos, Thailand, Vietnam].

Cymbopogon mekongensis là một loài thực vật có hoa trong họ Hòa thảo. Loài này được A.Camus mô tả khoa học đầu tiên năm 1920.