Gramineae

Common names

Rock three-awns

Arundinoideae, Aristideae. There are 290 species of Aristida in temperate and subtropical parts of the world.

Endemic to South Africa, where it occurs on rocky outcrops in savanna vegetation in the north-eastern parts of the country.

A densely tufted perennial that grows to a height of 700 mm tall. Leaf blades are up to 150 mm long. Spikelets 15-30 mm long (including awns). Plant branched at all the upper nodes; lower glume (including awns) 2/3 length of upper glume, awned; lemma without articulation; column of variable length; central awn sometimes solitary, lateral awns absent or weakly developed being very much shorter and more slender; callus tip naked, swollen, obtuse to truncate.

This is a hard unpalatable grass with no grazing value. It is one of the best grasses for making brooms.

Chromosome base number, x = 11 & 12.

C₄ photosynthetic pathway.

None reported and considered to be non-toxic.

Endemic to the Savanna biome of South Africa, where it is most commonly found in Sour Bushveld (Acocks 1988). Grows in shallow soils in between rocks and in rock crevices, and pockets on dry rocky outcrops and hillsides. Rainfall is approximately 600-900 mm per annum where this species occurs and the environment it is hot despite the altitude (1,200-1,500 m above sea level). It usually occurs with Faurea saligna, Protea caffra, Englerophytum magalismontanum, Vangueria infausta, Diheteropogon amplectens, Canthium mundianum, C. gilfillanii, Rhus magalismontana, Cymbopogon validus, Ancylobotrus capensis and Themeda triandra (Acocks 1988, Panagos 1999) on outcrops of sandstone of Witwatersrand Group geological origin.

Requires sandy soil.

Not cultivated.

Flowers from December to May.

None known

Slow-growing, but persistent once it is established.

Acocks, J.P.H. 1988. Veld types of South Africa (3rd edn.). Mem. Bot. Surv. S. Afr. No 28. Government printer, Pretoria.

Gibbs-Russell, G.E., Watson, L., Koekemoer, M., Smook, L. Barker, N.P., Anderson, H.M., Dallwitz, M.J. 1989. Grasses of southern Africa. Memoirs of the Botanical Survey of South Africa, No. 58, National Botanical Institute, Pretoria.

Low, A.B. & Rebelo, A.G. (eds.) 1996. Vegetation of South Africa, Lesotho and Swaziland. Companion to the vegetation map of South Africa, Lesotho and Swaziland. Dept. of Environmental Affairs and Tourism, Pretoria.

Panagos, M.D. 1999. A scale phytophysiognomic classification of the Suikerbosrand Nature Reserve. Unpublished report for Directorate of Nature Conservation, ARC-Range & Forage Institute, Pretoria.

Van Wyk, E. & Van Oudtshoorn, F. 1999. Guide to grasses of southern Africa. Briza Publications, Arcadia, South Africa.