THE TRITICUM REPENS. 93 



an umbel, and give the grass, when in bloom, a very peculiar 

 and characteristic aspect. 



But if the Cynodon dactylon is rare in cultivated fields, 

 the Triticum repens commonly called couch-grass, but, in 

 our opinion, the true and, genuine dog's-tooth is particularly 

 abundant. (See Fig.^2^.') Its long subterranean stems in- 

 crease with astonishing rapidity, and if the smallest frag- 

 ment be left in the soil, it will vegetate, and speedily extend 

 itself, until it becomes almost impossible to extirpate it. 

 It is a kind of wild barley, with stiff leaves of a moderate 

 length, and of a bluish tint, and a double spike, composed 

 of clusters of four to six flowers, each crowned by a narrow 

 ridge. We must not confound the Triticum repens with the 

 Elymus caninus of Linnaeus, which has no trailing under- 

 ground roots like the former. It differs also from the 

 latter in the roughness of each side of its leaves, only one 

 side of the leaf of the Triticum repens being rough, and in 

 the crests which rise above the flowers. 



Was the dog's-tooth known to the ancients? Undoubt- 

 edly, for the dog's-tooth flourishes in all climates, is truly 

 cosmopolitan. But it is difficult to decide whether their 

 Agrostis and their Gramen apply to the above-mentioned 

 species. 



According to Diodorus, the primitive Egyptians lived 

 upon herbs. "They also eat," he says,* "the stems and 

 roots which grow in the marshes. Especially did they 



* Diodorus, i. 43. 



