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THE AMERICAN NATURALIST [Vol. XLV 



plants which answer the description of the variety men- 

 tioned in the Prodr omits, more or less. It is more than 

 probable that these plants, the flowers of which exhibit 

 a great variation in color, are to be included under the 

 "variegated alfalfas," for which Westgate 31 suggests 

 the designation "Medicago falcata X (M. sativa), to 

 indicate that "the hybrids have been recrossed several 

 times with ordinary alfalfa and also among themselves." 

 Hybridization, however, does not explain the white 

 color of the flowers. That white-flowered plants and 

 those with flowers of a yellow or cream color are not of 

 rare occurrence is shown by the data furnished by 

 Westgate* 8 who notes such plants among four, respect- 

 ively five of the forms experimented with. On the other 

 hand, in view of the known existence of white-flowered 

 forms the assumption of the formation of the white- 

 flowered plants at Ann Arbor, through recent mutation, 

 does not seem warranted. At the same time, such a 

 possibility is not excluded, for while we do not believe 

 that hybridization can have as its direct result the pro- 

 duction of a new character, or the loss of one, 33 it is 

 not at all improbable that hybridization indirectly may 

 cause a plant to initiate a mutation period. It is ex- 

 pected that the seed gathered from the white-flowered 

 plants will, in the course of a generation or two, yield a 

 pure white offspring. This seems to be the experience 

 of others. Mr. C. V. Piper, of the Bureau of Plant In- 

 dustry, U. S. D. A., in a reply to a recent letter concern- 

 ing alba varieties of Medicago sativa says: "Some of 



Westgate, J. M., "Variegated Alfalfa," U. S. D. A., B. P. I., Bull. 



