GENERA OF GRASSES OF THE UNITED STATES. 89 



found at altitudes of 12,000 to 14,000 feet. In some species there are 

 two spikelets at the nodes of the rachis. This is especially frequent 

 in A. smithii and allies it with Elymus. 



In general, all the species of Agropyron are forage grasses. They 

 form an important part of the forage on the western range and in 

 the valleys often grow in sufficient abundance to produce hay. 



For a revision of the species of Agropyron found in the United 

 States, see Scribner and Smith, U, S. Dept. Agr., Div. Agrost. Bull. 



4:25-36. 1897. 



34. TBITICUM L. 



Spikelets 2 to 5 flowered, solitary, sessile, placed flatwise at each 

 joint of a continuous or articulate rachis, the rachilla disarticulating 

 above the glumes and between the florets or continuous; glumes rigid, 

 3 to several nerved, the apex abruptly mucronate or toothed or with 

 one to many awns; lemmas keeled or rounded on the back, many- 

 nerved, ending in one to several teeth or awns. 



Annual, low or rather tall grasses, with flat blades and terminal 

 spikes. Species about 10, southern Europe and western Asia; none 

 in the United States except Triticum aestiwum, the cultivated wheat. 



Type species : Triticum aestivum L. 



Triticum * L., Sp. PI. 85, 1753 ; Gen. PI., ed. 5, 37. 1754. Linnaeus describes 

 seven species, T. aestivum, T. hybernum, T. turgidum, T. spelta, T. monocoocum, 

 T. repens, T. caninum. The citation in the Genera Plantarum is to Tournefort's 

 figures 292 and 293 which represent, the first, beardless wheat, and the second, 

 bearded wheat. These two forms, beardless and bearded, are named by Lin- 

 naeus T. aestivum, the bearded wheat, and T, hybernum, the beardless wheat. 

 Triticum aestivum is chosen as the type because it has priority of position in 

 the Species Plantarum. Linnseus divides the genus into two groups, " annua " 

 and " perennia." The latter group, including Triticwm repens and T. caninum, 

 is now referred to Agropyron. 



Zeia Lunell, Amer. Midi. Nat. 4 : 225. 1915. Based on " Triticum spelta 

 Linn." Agropyron Gaertn. is included in the genus proposed. 



The most important species of Triticum is the cultivated wheat, 

 T. aestivum L. (T. vulgare Vill., T. satiwtm Lam.). A large 

 number of varieties are in cultivation, some with smooth lemmas, 

 some with velvety lemmas, some with long awns (fig. 44), some awn- 

 less (fig. 44, A). Durum wheat and club wheat are races, each with 

 several varieties. Triticum monococcum L., einkorn or 1-grained 

 wheat, is grown sparingly in Europe. Triticum dicoccwm Schrank, 

 emmer, is cultivated in this country as a forage plant. In emmer the 

 axis breaks up into joints, each joint bearing a spikelet which re- 

 mains entire, each floret permanently inclosing its grain. 2 



1 In the Species Plantarum the word appears in the plural, Tritica, probably inadvert- 

 ently. 



2 For a classification of wheats, see Jessen, Deutschlands Graser 191, 1863; Kornicke, 

 Handb. Getreidebaues 1: 40, 1885; Hackel in Engl. and Prantl, Pflanzenfam. II, 2: 80, 

 1887 ; True Grasses, translated by Scribner and Southworth, 180, 1890 ; Schulz, Mitt. 

 Natf. Ges. Halle 1: 14. 1911. For an account of T. dicoccoides Korn., recently found by 

 Aaronsohn on Mount Hermon, Palestine, see Aaronsohn, Verb. Zool. Bot. Ges. Wien 59: 

 485, 1909; U. S. Dept. Agr., Bur. PI. Ind. Bull. 180: 38, 1910; Cook, U. S. Dept. Agr., 

 Bur. PI. Ind. Bull. 274. 1913. 



