Tennessee Flora. 41 



in the Caucasus and adjoining territories. First vestiges of 

 its culture are found in the Swiss lake dwellings. M. 



TRITICUM L. 



Triticum sativum L. Wheat. The origin of culture of the 

 wheat in several varieties reaches back into prehistoric times. 

 Grains are found embedded in Egyptian and Assyrian tiles. 

 Indian and Hindoo myths relate its early use, as do likewise 

 the sacred writings of the Hebrews. In our time we distin- 

 guish the following varieties, some of which are extensively 

 cultivated in this State : 



T. sativum hibernum L. Winter wheat. 



T. sativum aestivum L. Summer wheat. 



T. sativum nudum L. Unbearded wheat. 



T. sativum album L. White wheat. 



T. sativum rubrum L. Red or Mediterranean wheat. 



The following species and varieties are less common in cul- 

 tivation and hav^e, perhaps, never been tried in Tennessee : 



T. turgidum and T. compositum L. Turgid wheat. The 

 latter is only a subvariety. The spikes of T. compositum are 

 compound or ramified. It yields very heavy crops, and is 

 best adapted to warm climates. 



T. durum Desf. T. rubrum Kunth. Hard or horny wheat. 

 Cultivated principally in Northern Africa and in Southern 

 Spain. 



T. Polonicum L. Grown mainly in Russia. 



T. Spelta (L.) Spelt. This species is extensively culti- 

 vated in Southern Germany, Hungaria, and Russia in the fer- 

 tile heavy red clay soils of these countries. It forms very 

 large and heavy grains which adhere to the chaff from which 

 they have to be separated like the chaff of the rice. 



T. dicoccum Schrank. Two-grained wheat; adapted to 

 high altitudes, resisting severe cold. 



T. monococcum L. Single-grained wheat, reserved for the 

 poorest rocky soils which would not support other varieties. 



HORDEUM L. 



Hordeum nodosum L. H. pratense Huds. Wild barley. 

 Dry, rocky places. O. S. May, June. 



Hordeum pusillum Nutt. Similar localities like the former. 

 O. S. May, June. 



H, distichum I^. Two-rowed barley. Long-eared barley. 

 Heads flattened and two-ranked, husk attached to the grain. 

 Cult. 



H. distichum Zeocriton L. Battle-door barley^ a variety of 

 the former. Cult. 



