TWO TYPES OF PROLIFERATION IN ALFALFA. 13 



to indicate vegetative propagation. Later in the season other plants 

 were found at Highmore having root proliferation remarkably de- 

 veloped, but they were all from seed bearing the S. P. I. number 

 mentioned, and all conform in a general way to the same type with 

 respect to growth aboveground. There is no definite evidence re- 

 garding the period in the plant's life in which proliferous roots are 

 first developed. There are some data, how T ever, to indicate that these 

 roots are not produced until the plant is at least 2 years old. 



The production of proliferating roots in alfalfa seemed so ab- 

 normal as to indicate a possible pathogenic condition such as might 

 be caused by crown-gall. The external symptoms of this disease, 

 however, are not visible, and a careful microscopic examination of 

 live material failed to disclose the presence of pathogenic organisms 

 of any kind. 1 



Critical studies are now under way to determine as fully as pos- 

 sible the conditions which induce the roots to produce new plants. 

 In this connection the point of origin of the later roots, the swell- 

 ings on the roots, and the buds on the swellings and other portions 

 of the roots are being aiven careful consideration. Field studies are 

 also being made to determine the life history of these shoot-bearing 

 roots, the conditions favorable to their development, and the possibil- 

 ity of utilizing the character which they represent in the development 

 of strains of alfalfa particularly adapted to severe conditions. No 

 prediction is ventured regarding the agronomic value of the pro- 

 liferous root character, especially since it is not know r n to what 

 extent this character is transmitted or whether cultural conditions 

 influence its development. Close and open fertilized seed has been 

 secured from plants possessing proliferous roots and will be sown in 

 the spring of 1913. New plants have already been produced from 

 stem and root cuttings, so that abundant material should soon be 

 available for use in determining many of the points that are now 

 unsettled. 



1 Dr. Ei-win F. Smith, of the Bureau of Plant Industry, examined the material for crown- 

 gall and other disease-producing organisms. He found nothing to indicate that the 

 production of proliferous roots in the specimens which he examined was in any way 

 pathological. 



[Cir. 115] 



