Tragus, commonly called bur gras, burr grass or carrot-seed grass, is a genus of plants in the grass family. It is native to Africa, Australia, and Eurasia with several species on islands in the Atlantic, Indian, and Pacific Oceans plus one species in Argentina.Haller, Albrecht von. 1768. Historia Stirpium Indigenarum Helvetiae Inchoata 2: 203Tropicos, Tragus HallerAusgrass2, Grasses of Australia
Plants are monoecious, stoloniferous, and either annual or perennial depending on the species. The genus has been introduced in subtropical and tropical areas around the world as weeds of disturbed areas. The culms (stems) are ascending or low and mat forming, glabrous, and circular in cross-section. Blades are flat or folded and linear, ligules membraneous and trichomatous. Flowers are born in narrow panicles; the primary branches are spirally arranged, each possessing 2-5 spikelets; each of these spikelets bears a single floret. Each floret has 3 stamens, the anthers of which are pale yellow. The caryopses (grains) are elliptical and golden-brown.Flora of China, Vol. 22 Page 495 锋芒草属 feng mang cao shu Tragus Haller, Hist. Stirp. Helv. 2: 203. 1768. Altervista Flora Italiana, Lappola, European Bur Grass, Klettengras, Tragus à grappes, Carretes, Tragus includes photos and distribution maps
Four species of Tragus have been introduced to North America: T. australianus, T. berteronianus, T. heptaneuron, and T. racemosus.Biota of North America Program 2013 county distribution maps The natural chromosome count is 2n = 20 in T. berteronianus, and 2n = 40 in T. racemosus. Tragus species utilize C4 photosynthesis. They prevent erosion, but make for poor grazing and in larger numbers indicate overgrazing.Tragus koelerioides
Species Seven species are accepted.Kew World Checklist of Selected Plant Families Tragus andicola – Argentina (Catamarca, Jujuy, Salta, Tucuman) Tragus australianus – Australia, New Caledonia Tragus berteronianus – Africa, Arabian Peninsula, Iran, Afghanistan, Pakistan, China; introduced in North America, West Indies, South America Tragus heptaneuron – Somalia, Kenya, Tanzania Tragus koelerioides – Zimbabwe, Namibia, Botswana, Lesotho, South Africa Tragus mongolorum – Mongolia, China, Indian subcontinent, Indochina, Madagascar, Mauritius, Réunion Tragus racemosus – Africa + Eurasia from France and Canary Islands to South Africa to Kazakhstan
formerly included several species have been placed in other genera – Brachypodium, Bromus, Festuca, Leptothrium, Lolium, Pseudechinolaena, etc.
References
External links Plants of Hawaii Gallery: Tragus berteronianus (Non-Native) Flora of America: Illustration of Tragus bertonianus and T. racemosus