MEDICAGO FALCATA, A YELLOW-FLOWERED 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 
falcata, 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. 
Fie. 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. sativaXfalcata 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 Medicago 
falcata have been based chiefly on the fact that it grows naturally in 
very dry situations and possesses certain characteristics which are or- 
dinarily considered as drought-resisting adaptations. Nocritical data 
are available from plants grown under cultivation, but the general 
results leave little doubt that most of the forms of Medicago falcata 
are relatively drought resistant, and certain forms at least will endure 
drought conditions too severe for Medicago sativa. 
The factors that are potent in enabling it to resist drought are its 
extensive root development, its ability to produce rhizomes well be- 
