i>r>s 



MISCELLANEOUS STUDIES 



narrow ; under unfavorable weather conditions the flowers are often few 

 and defective, while the leaves are resistant and long-lived (fig. 11). 

 Figures 12 and 13 show well the coarse leaves and lateness of well 

 developed large-leaved plants in the 1915-16 cult'ures, the plants in 

 the latter figure being several weeks the older. 



The results of the progeny tests are given in tables 26 and 27. All 

 the twenty large-leaved individuals tested have given mixed progeny; 

 the proportion of the mutant type, though much larger than with 



TABLE 27 

 Large-leaved type: heredity. Summary. 



Mainly from unguarded flowers; see table 26. 



b Eespectively 72.2 and 37.3 per cent of the numbers of seeds planted. 



smooth-leaved, approximates to 50 per cent, not 75 per cent, with little 

 indication of selective elimination with poor germination. 10 



Here plainly, as with smooth-leaved, no pure mutant-type parent 

 has yet been tested. Since this is also true of the other types, aside 

 from early, that have been somewhat extensively tested, and fifty-three 

 mutant-type parents in all have given Snowflake progeny, it is prob- 

 able that homozygous individuals of these types seldom or never 

 develop. The actual adult ratio with large-leaved is plainly not 2 : 1. 

 but rather 1 : 1, a fact that would suggest absence of the mutant-type 

 factor or factors from the pollen. The small trial cultures started 

 in 1917, however, show that the type is carried by both sperm and 

 eggs. 



is Since hybrids are of the mutant type in appearance, the possible cross 

 pollination by Snowflake parents could hardly give Snowflake progeny with any 

 pure large-leaved parent. It may, however, have reduced slightly the proportion 

 of large-leaved progeny from heterozygous parents of this type. 



[1261 



