14 BURSA BURSA-PASTORIS AND BURSA HEEGERI : 



Ohio, May 28 and June 2, 1905. The climax leaves of the parent were of 

 the most pronounced heteris form. From seeds sown June 26, 1905, 39 

 specimens were grown, all of which agreed with the parent and with each 

 other in the character of lobes as described, though there was some fluctu- 

 ation in general aspect due to difference in elongation of the rachis by 

 means of which the lobes were more or less crowded, some variation in the 

 attenuation of the primary lobes, in the degree of lobation of the upper 

 rosette leaves, in the angle which the rosette leaves made with the hori- 

 zontal, and in the prominence of the rounded secondary lobe. This sec- 

 ondary lobe was characteristic, however, and in not a single individual was 

 it absent in the climax leaves of the rosette. 



The significance of several of these variations was tested by using their 

 best representatives as parents of a second generation. From 3 of these 

 (053.30, 053.31, 053.32) have been raised 839 specimens, all but the 

 54 offspring- of one individual being strictly like the grandparental and 

 parental form. The one aberrant family (053.30), the parent of which had 

 the upper leaves of the rosette less deeply lobed than usual, showed com- 

 plete suppression of lobes in 5 individuals, and in the remaining' 33 which 

 were noted the primary lobes were broader than usual and the secondary 

 lobes less prominent. It is desirable to test the possibility that these char- 

 acteristic secondary lobes may be rendered completely latent by selection, 

 and, if this is possible, to discover by what means they may be again made 

 manifest. 



At least two other pure-bred cultures coming in from nature belong- to 

 B. bp. heteris, but were considered for two generations to represent two 

 very distinct elementary forms. It has been the striking modifications ob- 

 served in these two pedigrees which have led me to suspend judgment on 

 all my cultures except those whose behavior in hybrid combinations has 

 left no possible question as to their distinctness and permanence. 



The basis for the assumption that these two pedigrees represented dis- 

 tinct elementary species was the facts that the aspect of each of these fam- 

 ilies was very different from that of any other culture and that there was 

 great uniformity among the individuals belonging to either single family, 

 i. e. , while there was a strong break between the families there was almost 

 no variation within the family. This was presumably the basis of Alm- 

 quist's estimates as to the distinctness of his forms, and the following ac- 

 count of these two families supports my attitude of doubt as to the soundness 

 of his results. 



040.15: This specimen was found growing in Jackson Park, Chicago, 

 by Charles A. Shull, who collected the seeds in the summer of 1905. Climax 

 leaves taken from the rosette show only a slight development of the heteris 

 characters as described above (fig. 3 ) . Though the sinuses reached the mid- 

 rib, the primary lobes were not sharply attenuate, and the secondary lobes, 



