8 BXJLLETIK 428, U. S. DEPARTMENT OF AGRICULTURE. 



10,000 and 11,000 feet, in a region surrounded by glaciers and cov- 

 ered with snow during the winter months. 



With regard to temperature, there are few perennial species that 

 are found growing naturally under the extremes of heat and cold 

 that occur throughout the natural range of Medicago falcata. In 

 parts of India and southwest Asia it is subjected to extremely high 

 summer temperatures, but is exposed to only a moderate winter 

 climate. In the vicinity of Yakutsk, Siberia, it meets with hot, dry 

 summers and temperatures as low as — 84° F. during the winter. Be- 

 tween these extremes it is found growing naturally under equable 

 climatic conditions in parts of western Europe, notably in Spain 

 and France and in the Scandinavian Peninsula. 



Growing as it does under such a great variety of conditions — m 

 many cases remote from the influence of agriculture or commerce — it 

 is not surprising that the species has developed many forms and that 

 it exhibits a tendency toward the production of types peculiar to the 

 various natural geographic regions. That such is the case is strongly 

 indicated by the many introductions made by the Department of 

 Agriculture from numerous localities. However, it will require care- 

 ful and extensive investigations to determine to what extent in this 

 species plant type is correlated with natural conditions. The mate- 

 rial which the department has succeeded in obtaining shows rather 

 clearly that the forms from the high steppe regions of Russia and 

 Siberia are in general quite different from those commonly found in 

 northern India and from at least some of the forms found in south- 

 ern Russia. 



From the vicinity of Irkutsk, Siberia, the department has obtained 

 a distinct form, apparently peculiar to that region, which is character- 

 ized by its broad crown and very fine decumbent stems. This region, 

 it will be noted, has a normal annual precipitation of 13 to 19 inches, 

 fairly well distributed throughout the year. The extremely broad- 

 crowned decumbent forms have been procured only from southern 

 Russia in the general region represented by the Provinces of the Don 

 Cossacks and Kharkof. The forms commonly found in India ap- 

 proach sweet clover {Melilotus alba) -in general appearance, espe- 

 cially in color and texture of foliage, and are quite distinct from 

 those of the high steppes of Russia and Siberia. So far as the ma- 

 terial in the possession of the department indicates, the closest re- 

 semblance to the forms from India is found in certain forms pro- 

 cured from southern Austria and said to be native to that region. . 



BOTANICAL HISTORY. 



The accounts of Medicago falcata appearing in old literature are 

 chiefly botanical, and in most cases very brief. However, they are 

 sufficiently clear to indicate that the species was well known, at least 



