234 



MISCELLANEOUS STUDIES 



discovered; the occurrence of the various types suggests a random 

 distribution among the progeny lots. This conclusion is confirmed, 

 and extended to CG2, by the field-sown lots of 1911. 



Various parents belonging to mutant types have given other 

 mutant types among their progeny. There is some reason, as table 4 

 indicates, to suppose that parents of the early type have a more 

 marked tendency to produce these other types than have Snowflake 

 parents. 8 



TABLE 4 



1910 and 1911F; sown in greenhouse. Apparent mutants among descendants 



of WG9-C10 and other ancestors, comparing early parents (pure or 



heterozygous) with SnowftaTce parents. 



a For the calculation of these probable errors the percentages on the last line 

 are used as p. 



CHARACTERISTICS AND HEREDITY OF MUTANT TYPES 

 1. THE EAELY TYPE 



So far as is known, "WG9-C10 (figs. 1, 2) was the only apparent 

 mutant of the early type in the cultures. Since, however, this 

 type visibly differs from Snowflake only or mainly in quantitative 

 characters, it cannot be positively identified without comparative 

 progeny tests, and therefore may have been represented by mutant 

 individuals not used as parents. WG9-C10 was much smaller pro- 

 portionately than were its progeny; this difference was probably due 

 to an embryonic abnormality, early blind termination of the main 

 axis, which was occasionally observed elsewhere and probably occurred 

 in this case. Plants of this type, as compared with Snowflake, are, in 

 general, fewer-noded, smaller, and earlier in blooming. 



The principal data from the cultures of 1908 are shown in tables 

 5 and 6, which also indicate the later conclusions as to the segregation 

 of the early type in the cultures of this year ; figures 3 and 4 illustrate 



8 Inspection of the data in detail indicates that this difference is not due to 

 the possible tendency in parents grown in the warm house to more frequent 

 apparent mutation. 



F921 





