Tragus (plant)

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Tragus
Tragus australianus
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Embryophytes
Clade: Tracheophytes
Clade: Spermatophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Subfamily: Chloridoideae
Tribe: Cynodonteae
Subtribe: Traginae
Genus: Tragus
Haller 1768 not Panz. 1813
Type species
Tragus racemosus
(L.) All.
Synonyms[1]
  • Echisachys Neck.
  • Echinanthus Cerv.
  • Lappago Schreb.
  • Nazia Adans.

Tragus, commonly called bur gras,[2] 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.[3][4][5]

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.[6][7][8]

Four species of Tragus have been introduced to North America: T. australianus, T. berteronianus, T. heptaneuron, and T. racemosus.[9] The natural chromosome count is 2n = 20 in T. berteronianus, and 2n = 40 in T. racemosus.[10] Tragus species utilize C4 photosynthesis. They prevent erosion, but make for poor grazing and in larger numbers indicate overgrazing.[11]

Species

Seven species are accepted.[12][1]

formerly included[1]

several species have been placed in other genera – Brachypodium, Bromus, Festuca, Leptothrium, Lolium, Pseudechinolaena, etc.

References