|
''Tragus'', commonly called burr grass or carrot-seed grass, is a genus of plants in the grass family. It is native to Eurasia, 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: 203〕〔(Tropicos, ''Tragus'' Haller )〕〔(Ausgrass2, 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.〔(RLEM 610 grass taxonomy tragus )〕〔(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''.〔http://herbarium.usu.edu/treatments/Tragus.htm〕 ''Tragus'' species utilize C4 photosynthesis. They prevent erosion, but make for poor grazing and in larger numbers indicate overgrazing.〔(Tragus koelerioides )〕 ;Species〔(Kew World Checklist of Selected Plant Families )〕〔(The Plant List search for ''Tragus'' )〕 # ''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 pedunculatus'' - Namibia, Botswana # ''Tragus racemosus'' - Africa + Eurasia from France and Canary Islands to South Africa to Kazakhstan ;formerly included〔 several species now regarded as better suited to other genera: ''Brachypodium Bromus Festuca Leptothrium Lolium Pseudechinolaena'' ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tragus (plant)」の詳細全文を読む スポンサード リンク
|