MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 

 B. Second generation 



263 



The splitting into three types in the cross Oe. suaveolens x La- 

 markiana is obviously analogous to that of the first generation of 

 Oe. Lamarckiana x Oe. grandiflora and points to a mass mutation 

 as discussed above. 



Summary 



1. Oenothera suaveolens Desf. has produced in my cultures, since 

 1912. half a dozen of different mutants, some of which are the same 

 as those observed in allied species. The coefficients of these changes 

 were 1 — 3 percent or lower. These phenomena happen in the same 

 manner as in the other mutating species of Onagra and evidently 

 depend upon the same internal and external causes. 



2. The mutations, parallel to those of related species, were called 

 lata, sulfurea and lutescens. The first occurs also in Oe. Lamarckiana, 

 the second in Oe. biennis and the third in Oe. grandiflora. Their 

 coefficients of mutation were 0.7, 0.1 and 1—3 percent. 



3. Among the special mutations one is of a taxonomic nature, viz., 

 Oe. suaveolens mut. apetala, with flowers without petals. This charac- 

 ter is specific in some species of the allied genus Fuchsia. The mutant, 

 however, had the characteristics of a half-race, having also flowers 

 with four petals besides all the intermediates. 



4. Two narrow-leaved types occurred: Oe. mut. fastigiata with 

 erect branches, and Oe. mut. jaculatrix with almost linear leaves. 

 Their coefficients of mutation were 0.5 and 1 percent. 



5. The mutant lata is an inconstant type, splitting into about 

 25 percent lata and 50 percent suaveolens, and producing besides 

 these as high as 25 percent lutescens. It repeats almost all the special 

 characters of Oe. Lamarckiana mut. lata. 



6. Oe. mut. sulfurea and mut. lutescens are constant types, but 

 their characters are visibly inherited in the first generation through 

 the gametes of one sex only. 



7. Oe. mut. fastigiata and mut. jaculatrix are also constant, in 



