Breeding experiments which show that hybridisation and mutation etc. 223 



the Fl of rubricalyx x nanella was used in 1910 to pollinate grandi- 

 flora. The results of this cross are described in the present paper. It 

 will be seen that the rubricalyx parent contained the dwarf nanella 

 in a recessive condition. The dwarfs appeared again in the F2 (vide 

 infra). 



If we now consider the parents of the reciprocal cross, rubricalyx x 

 grandiflora, which was made in 1909, the grandiflora parent came 



Fig. 6. Rosette of Birkenhead race of 0. grandiflora. 



from a wholly different source and, unfortunately perhaps, differed 

 slightly from the Alabama form used in the other cross, though it was 

 a typical grandiflora. It came from the sand dunes of Birkenhead, 

 England, where Oenotheras have long been naturalized, and was 

 cultivated as race No. 40 from that source. A mmiber of these races 

 are described elsewhere (Gates, 1913 a, p. 43^. The buds of this race 

 No. 40 were typical grandiflora in every respect, as wers also the 



