Recent Papers on CEnothera Mutations. 302 



only corroborated the independent results of Miss Lutz and Gates 

 regarding the constancy of the fifteen chromosomes in O. mut. lata, 

 but have found the same number constantly in semilata and also in 

 two cases in which lata foliage, occurring as a mutation, is combined 

 with other characters inherited from the parents.' 



Thus 0. biennis mut. lata appeared in a race of normal O. 

 biennis , having lata foliage and biennis flowers (15 chromosomes). 

 Again. 0. mut. lata rnbricalyx occurred in the F^ of 0. rubricalyx 

 X 0. grandiflora. The great bulk of these plants were blends and 

 combinations of the characters of the parents, but lata rubricalyx 

 had lata foliage and habit together with the red pigmentation of 

 rubricalyx. The possession of fifteen chromosomes by this plant 

 also shows that whenever a meiotic irregularity leads to the 

 formation of an individual having an extra chromosome, such a 

 plant will have the leaves and habit of lata or semilata.^ It further 

 shows the sharp contrast which must be drawn between sporadic 

 mutations and the regular processes of inheritance either in pure 

 races or in hybrids. 



We may conclude that the work of De Vries and other students 

 of CEnothera has resulted in showing that really new characters 

 may and do arise by a germinal change, and are not merely 

 recombinations of the characters of hybrids. The importance of 

 this conclusion is very great at a time when we have been asked to 

 suppose that all evolution has been accomplished by the shuffling 

 and successive loss of fixed Mendelian unit-characters. 



' Evidence which shows that Mutation and Mendelian splitting are 

 different processes. Section K, British Association, Birmingham. 



' It is possible that one of two other mutants also have an extra 

 chromosome. 



