55 



of Caucasian Alts, and Transcaucasia generally, especially 

 Armenia. 



\ . I\r. platy carpa. Firs, yellow. Pods large and flat. Stems 

 hard and smooth, almost trailing. Central & S. C. Siberia. 



\'I. AI. ruthenica. Firs, yellow. Pods flat and oval, tapering 

 toward both ends. Low growing type. Distribution, in general, 

 north of AF sativa grows in dry. stony soils, almost pure sand. 

 Lake Baikal, Siberia, to Pacific Ocean. 



VIF M. arborea (L). Large bright yellow flrs. Largest 

 representative of genus M. Over 10 feet high. Native of ]\Ied. 

 region of Europe, Asia and Africa. Mentioned in ancient Greek 

 and Roman writers as "cytisus." Less productive, becomes 

 woody too (juickly. A'alue in hot dry places. Remarkable vigor 

 of growth. 



VIFF 'S\. radiata. This plant is placed in the genus Trigo- 

 ncllo by all recent botanists." 



GENERAL STRUCTl-RE OF M. .SATI\'.\. 



Roots. The alfalfa plant has a very strong, tough and deeply 

 penetrating root system, descending five feet in six months and 

 from ten to twenty feet or more where the conditions are favor- 

 able. It has been recorded that alfalfa roots penetrated 129 

 feet below the surface of a tunnel in Nevada. The tap root is 

 usually less than one-half inch in diameter below the crown, 

 though very old plants have reached the size of a man's ankle. 

 The large secondary roots extend directly downward with a slight 

 lateral tendency and bear numerous rootlets which in turn bear 

 elongate oval root tubercles, sometimes appearing in large 

 clusters. 



However, it should be noted tbat in some of our shallow Fla- 

 Vv'aiian soils the typical tap roots are absent and in their places 

 we find well developed branching roots which spread laterally 

 rather than downward. 



Stems. The young seedling has a single erect slightly hair\- 

 stem, but the older plant has a great number of stems arising from 

 the large crown and clipped stems. There are generally 20 to 30 

 stems six to sixty inches tall (usually 18" to 30''), while solitary 

 plants may have 150 to 200 stems and even more. 



A plant seven months old of the common L^tah variety grown 

 on the College Farm had 308 stems by actual count, and the 

 writer has seen a photograph'* of a six months old plant grown 

 imder irrigation at sixtv feet below sea level in southern Cali- 

 fornia which vvas a little less than eleven feet in height. 



Alfalfa sometimes has underground stems," some of which 

 may take root and produce new plants. 



Lcat'cs. The dark green leaves are pinnate, with three ovate- 



■ IT. S. D. AsrJc. B. p. I., Bui. 131. 



8 "Book of Alfalfa" — F. P. Cobnrn. 



» U. S. D. Agri., B. P. I., Oir. U.t. 



