Themeda

Themeda is a small genus of grasses in the family Poaceae, subfamily Panicoideae, and the tribe Andropogoneae. It comprises two widely accepted species, Themeda triandra and Themeda quadrivalvis, native to tropical and subtropical regions of Africa, Asia, and Australia. The genus is characterized by tufted perennial growth and inflorescences that are open panicles bearing spikelets.

Species in Themeda form dense tussocks with slender to lanceolate leaves. The inflorescence is a branched panicle that matures to brownish or reddish-brown seed heads. Spikelets are typical of Andropogoneae with two glumes at the base. Themeda grasses are adapted to warm climates and often tolerate drought and poor soils once established.

Native ranges vary by species, with Themeda triandra occurring across Africa, Asia, and Australia in savannas, grasslands, and open woodlands; Themeda quadrivalvis occurring in tropical Asia and Australia, commonly found in disturbed areas and pastures. Both species can thrive in sunny conditions and are frequently found along roadsides and in disturbed habitats.

In ecological and practical terms, Themeda triandra is notable for its role in native-plant restoration and as fodder in some grazing systems in Australia; it also contributes to soil stabilization and biodiversity in grassland ecosystems. Some populations of Themeda quadrivalvis have been described as weedy or invasive in non-native regions, prompting management in certain landscapes.

Taxonomic placement places Themeda within the Andropogoneae, with some sources recognizing taxonomic nuances and synonyms. The circumscription of species may vary among botanists.