1924] Collins: Inheritance in Crepis capillaris (L.) Wallr. 271 



in which this gene was present ; the former is, however, more probable, 

 for it has been shown in Drosophila (Sturtevant, 1921) that certain 

 loci are more mutable than others. Additional evidence that this is 

 the case is found in the fact that a similar variation, bald, has been 

 found to oecur in at least four other species, C. hiorsifolia, C. biennis, 

 C. aspera, and C. dioscoridis. A similar germinal diversity among 

 local races of Drosophila melanogaster from equally widely separated 

 localities has not been found, and Sturtevant suggests that this may 

 be due to a frequent transportation of individuals from one locality 

 to another. The chances are probably as great for transportation of 

 Crepis seeds along with agricultural seeds as for the transportation 

 of Drosophila among fruits. 



It is possible that some of these variations might have arisen from 

 mutations occurring in the cultures under observation. A study of 

 the wild plants in the fields about Eureka, however, disclosed the 

 fact that some of the forms obtained in the greenhouse by inbreeding 

 were also appearing there among wild plants. In tliis material it is 

 impossible to say whether any new recessive variation appeared as the 

 result of a recent gene mutation or the segregation of a recessive from 

 a heterozygous parent stock. 



Variations in Chlorophyll 



A number of different variations involving a loss of chlorophyll 

 have appeared. These variations are evident in the seedling stage, 

 but, unlike the usual albinic condition in seedling plants, most of these 

 albino types develop sufficient chlorophyll as the plant grows to enable 

 the plant to live. One type of pure white seedling always dies in the 

 seedling stage. The other types are either pure yellow or yellowish 

 green. The percentage of seedling mortality in these classes is higher 

 than in pure green seedlings. 



A complete analysis of the genetic relations of these different types 

 has not yet been possible, but a sufficient study has been made to 

 warrant a preliminary report in this general account of variations in 

 Crepis capillaris. 



CHLOEINA (C) 



Chlorina signifies a chlorophyll deficiency in seedling and mature 

 plants. The middle portion of the leaves of chlorina plants is yellow- 

 ish, but both tip and base contain more or less chlorophyll and thus 

 it is possible for the plant to function. This character first appeared 



