466 COBB AND BARTlvETT: INHERITANCE IN OENOTHERA 



It has been described and figured elsewhere (see footnote 2). 

 The flat-leaved mutations of strain C were mut. latifolia and 

 mut. gynocrates. The former, not infrequently produced by 

 both strains C and E, gives dimorphic progenies containing mut. 

 latifolia and f. typica. It, also, has already been described and 

 figured. ^^ Mut. gynocrates comes true from seed. It is not 

 one of the better known mutations, but was used in the 

 experiments because it happened to be in flower when the 

 crosses were made, and seemed, in spite of its dwarf habit, to 

 be a form of considerable vigor. 



Both mut. latifolia and mut. gynocrates have pollen that is 

 equivalent to that of the particular f . typica from which they are 

 derived. In view of the failure of the crosses in which the pollen 

 of f . typica C was used, it is especially important for the reader 

 to understand the basis for this conclusion, which is true not 

 only for these particular mutations, but for all others except 

 those that appear to be tetraploid or triploid. All the progenies 

 thus far grown from self-pollinated mut. latifolia have been di- 

 morphic, consisting of f. typica and mut. latifolia. The f. typica 

 from the dimorphic progenies breeds true, whereas the mutation 

 continues to split, in every generation. When mut. latifolia is 

 crossed with pollen of f . typica, the Fi generation is quite like that 

 resulting from self-pollination. Moreover, when pollen of the 

 mutation is used in crosses with f. typica or its other mutations, 

 nothing is obtained in the Fi or subsequent generations which 

 would not have resulted from self-pollination. Double reciprocal 

 crosses still further substantiate the identity of the pollen of 

 mut. latifolia with that of f. typica. 



The same facts apply to mut. formosa, except that its progenies 

 do not contain f. typica. It shows the same matroclinic inheri- 

 tance in crosses with other forms belonging to the E strain. Cul- 

 ture records bearing out the conclusions that have been made 

 with regard to the equivalence of its pollen with that of f. typica 

 E and mut. latifolia E are given in table i. The records are in 



1^ TuppER, W. W., and Bartlett, H. H. The relation of mutational characters to 

 cell size. Genetics 3: 93-106. 1918. 



