16 ' BURS A BURSA-PASTORIS AND BURS A HEEGERI : 



though present, were not strongly marked. The seeds were sown in the 

 propagating-house December 27, 1905, and produced 106 offspring, all of 

 which had a peculiar grayish aspect, owing to the fact that the leaves were 

 freely dotted with small specks of red. The rosettes were very lax, the 

 relatively few leaves made a rather wide angle with the horizontal, and the 

 leaves, while possessing both the primary and secondary lobes, had the 

 latter small and angular and little more marked than serrations borne by 

 the primary lobe, which all experience up to the present time indicates are 

 of only fluctuating value. (See fig. 4.) All had simple slender stems 

 which came to bloom in 3 to 4 months from the time the seeds were sown 

 as compared with 8 months required by the above-described family of 

 typical B. dp. heteris. 



Self-fertilized seeds of two of these plants (0515.95 and 0515.96) were 

 sown in May, 1906, and gave uniform progenies, but having an aspect quite 

 different from that of the parent generation just described. Although the 

 rosettes in this second generation were strongly ascending and were few- 

 leaved, as in the preceding generation, the texture of the leaves was much 

 less firm, the grayish aspect was wholly lost, owing to the absence of the 

 red specks, and secondary lobing was also much reduced, giving a condition 

 resembling the grandparent as it grew in nature (cf . figs . 3 and 5 ) . The con- 

 ditions in the propagating-house during the development of these families 

 were unsatisfactory, and their great change from the characteristics of the 

 preceding generation did not shake my faith in their distinctness from my 

 other types, since within the family there was still great uniformity, seem- 

 ing thus to demonstrate that whatever differences were observed were due 

 to the differences in environment during the time of development of these 

 two generations. 



An average specimen from one of these two families was chosen as the 

 parent of a third generation. The pollination of this plant (0695.158) was 

 unguarded, but it was grown well separated from all other Burs a cultures. 

 The seeds were sown on November 1, 1906, and produced 213 plants, all 

 of which possessed well-marked the characteristics of B. bp. heteris , having 

 completely lost all the peculiarities which had led me to believe that this 

 pedigree belonged to a distinct biotype. (See fig. 6.) Other proofs that 

 040.15 was a specimen of B. bp, heteris were derived from hybrid families 

 formed by crossing its offspring with plants belonging to other biotypes. 

 Except in one case only the F x hybrids from these crosses have been 

 studied and they will not be considered in detail at this time, but these first- 

 generation hybrids showed the characteristics which they should have pos- 

 sessed if typical B. bp. heteris had been used . The one F 2 family (0693 . 203 ) 

 which has been reared from these hybrids will be considered later. (See 

 p. 42.) 



