CHAPTER XI 



LEGUMINOSAE 

 MEDICAGO SATIVA 



THE large pea family is widespread and contains a number of 

 species of economic plants, among which are Pisum sativum 

 L., Phaseolus vulgaris L., Trifolium pratense L., Medicago sativa 

 L., and many others grown for food or decorative purposes. The 

 clovers and medics are important forage plants, and alfalfa is an 

 outstanding representative of the group. A native of southwestern 

 Asia, where it was used as a forage crop centuries before the Chris- 

 tian era, it has spread successively to Greece, Italy, Spain, Mexico, 

 and South America. According to Bailey (i), it was introduced 

 into New York from Europe as early as 1791, and was cultivated 

 there in limited areas. It was brought into California from Chile 

 in 1854; and to Texas from Mexico in the early part of the nine- 

 teenth century. Since introduction, its production has extended 

 over the entire western half of the United States until it is now one 

 of the principal forage crops west of the Mississippi. 



There are approximately 55 species of the genus Medicago, of 

 which seven are perennial and one biennial or perennial. Al- 

 though the commonly grown alfalfa is known as Medicago sativa 

 L., it seems probable that many of the commercial strains are 

 hybrid forms. It has been suggested by Westgate (34), and by 

 Garver (ii), that crossing of M. sativa with the yellow-flowered 

 M. falcata has occurred, and that this has contributed to the 

 hardiness of northern strains of alfalfa such as Grimm, which is 

 classified as M. media by some authorities. Fryer (11) has con- 

 firmed this point on the basis of cytological evidence, stating that 

 "Cytological study has shown the chromosomes of Medicago 

 sativa, M. falcata (3i-chromosome form) and M. media to be the 

 same in number and very similar morphologically"; and he con- 

 cludes that "there is therefore no reason, from cytological con- 

 siderations, to doubt the origin of M. media from interspecific 

 hybridization between M. sativa and M. falcata." 



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