1924] Collins: Inheritance in Crepis capillaris (L.) Wallr. 279 



SUMMARY 



1. Plants of Crepis capillaris are largely cross-fertilized, and this 

 mode of reproduction operates to maintain a condition of genotypic 

 heterozygosity. 



2. Inbreeding wild plants thus produced results in the production 

 of a number of pure races which show loss of vigor and reduction 

 in size similar to the effects produced by inbreeding maize. 



3. Four sets of duplicate genes are found to be responsible for 

 the inheritance of four different characters. Two of these characters 

 are shown not to be linked. Duplicated genes do not indicate dupli- 

 cated chromosomes, for each pair is morphologically different from 

 the others, 



4. The recessive character 'bald' has appeared in a number of 

 unrelated strains. This is evidence that a certain locus in one 

 chromosome pair mutates more frequently in the same way than do 

 other loci. The appearance of bald in other species may be due to 

 a similar gene in each of these four species. 



5. Several types of chlorophyll variations have appeared. Some 

 show monohybrid recessive relations when contrasted with the normal 

 condition, while others show more complex relations. 



6. The different forms from widely separated localities show no 

 tendency to approach a common type when grown continuously in 

 the same place. 



It is with pleasure that the author acknowledges the helpful advice 

 given by Professor Babcock and Professor Clausen throughout the 

 progress of the work. 



