BIOTYPES AND HYBRIDS. 35 



saved as a seed-plant under the number 05184.145, and whose progenj- is 

 next described. 



05184.145 : This plant had the climax leaves of B. bp. /leteris, but in the 

 later rosette-leaves the rounded secondary was lost and the lobes then had 

 one to several rather sharp incisions on both proximal and distal margins. 

 Seeds of this plant were sown Jiine 20, 1906, and gave a progeny consist- 

 ing of 158 B. bp. heteris and 58 B. bp. tenuis, or 2.72 : 1. 



054.185 : This plant was selected as nearly the equivalent of its parent 

 (040.4). It had the lobes about evenly tapering and equally serrated on 

 both margins. Its seeds were sown February 23, 1906, and gave a large 

 progeny, which at one time suffered greatly from unsatisfactory conditions 

 for growth during the summer months. Of these stunted specimens 236 

 were discarded as modifications of B. bp. tenuis, but 50 equivalent speci- 

 mens transferred to larger pots showed that this determination was wholly 

 unsatisfactory. Well-grown specimens belonging to this family were later 

 shown to consist of 33 B. bp. heteris, 48 B. bp. tenuis, 5 B. bp. rhomboidea, 

 and 14 B. bp. simplex. It is plain that the manipulation of this family was 

 such that nothing of value can be derived from the ratios, but it is worth 

 noting that this plant, which was considered the equivalent of its parent, 

 produced a family composed of the same four forms which had appeared in 

 the parental famih^ 



054.186 : This plant had the lobes divided into rather narrow secondary 

 lobes by deep incisions on both distal and proximal margins. It had some 

 of the characters of both B. bp. heteris and of B. bp. rhotnboidea, but the 

 resemblance to neither was very striking. The seeds were sown February 

 23, 1906, and produced a progeny which was judged to consist of 30 B. bp. 

 heteris, 22 B. bp. rhomboidea, and 45 intermediate between these two. 

 These intermediate specimens differed from B. bp. heteris in the prominent 

 incisions on the proximal margin of the primary lobes. As these interme- 

 diate forms pretty completely bridged the gap between the two parental 

 biotypes, the wide departure from the ratio 1:2:1 was doubtless only ap- 

 parent, being due probably to the uncertainty of the judgment in separating 

 the several classes. This shows that B.bp. heteris is not always completely 

 dominant over ^. bp. rhomboidea, and the same fact will be noted in several 

 other cases. 



054.190: This was a well-marked specimen of B. bp. rhomboidea. Its 

 seeds were sown February 28, 1906, and gave a progeny of nearly a thou- 

 sand. Owing to the limitations of space in the propagating-house, only 

 123 of these plants were potted up for observation. One of these died. Of 

 the remainder, all but 1 were B. bp. rhomboidea: 1 differed from the rest 

 of the family in the elongation of the terminal portion of the lobes, this 

 being recognized as the character of the heterozygous condition of the 



