MEDICAGO FALCATA, A YELLOW-FLO WEBED ALFALFA. 45 



directly; that is, by determining the relative hardiness of their 

 hybrids with Medicago sativa, since many of them are of themselves 

 not of sufficient agronomic importance to justify the expense of 

 extensive tests of hardiness. Several introductions, however, includ- 

 ing two lots from India, which have been tested at the University 

 of Saskatchewan, Saskatoon, Saskatchewan, for three or more years, 

 show no perceptible difference in their ability to survive the winter 

 conditions. 



Taking into consideration the geographical range of Medicago 

 fdlcata^ the provisions made by its various forms for the protection 

 of the buds during the dormant season, and the results of tests in 

 this country and elsewhere, it is fair to assume that the species may 

 well be considered hardy as compared with the commercial strains 

 of Medicago sativa. Through this physiological characteristic the 

 various forms of the species will aid in solving the alfalfa problem 

 in the colder and drier portions of the United States. 



Fig. 19. — The hill plantings of alfalfa shown in figure 22. Photographed in May, 1911. 

 The solid plantation in the background is of Medicago falcata varieties. The scatter- 

 ing plants in the foreground are M. sativa and M. sativaX falcata strains. The 

 difference in winterkilling between the last two and the first was very marked. 



DROUGHT RESISTANCE. 



Within recent years the relation existing between drought resist- 

 ance and cold resistance has become more definitely recognized. The 

 adaptations of the plant which make it resistant to cold are now 

 believed to enable it in a large measure to endure or evade drought. 

 The prevailing opinions regarding the drought resistance of 7l!/(3^i(7«(7(9 

 falcata have been based chiefly on the fact that it grows naturally in 

 very dry situations and possesses certain characteristics Avhich are or- 

 dinarily considered as drought- resisting adaptations. No critical data 

 are available from plants grown undei- cultivation, but the general 

 results leave little doubt that most of the forms of Medicago falcata 

 are relatively drought resi.stant, and certain forms at least will endure 

 drought conditions too severe for Medicago .sativa. 



The factors tliiit nva potent in enabling it to resist drought are its 

 extensive root development, its ability to produce rhi/omes well be- 



