TWIN HYBRIDS OF OENOTHERA HOOKERI T. AND G. 



281 



"franciscana-Uke", whereas another type was biennis-\\ke. My cul- 

 tures confirmed this result and showed that these two types are 

 the main ones and that the numerous other combinations are only 

 the effect of minor marks and can, with a few exceptions, be con- 

 sidered as belonging either to the "franciscana-Uke" or to the "biennis- 

 like" group. Moreover this latter group duplicated the characters of 

 the hybrids of the first generation. 



The original cross for my cultures was made in 1915 and the first 

 generation consisted in 1916 of 60 plants, all of which showed the 

 same type. Forty-eight were biennials and did not make a stem, 

 but the remaining 12 flowered abundantly during August. They 

 were all like biennis in almost all their characters, but the leaves 

 were narrower, their color paler, the spikes less dense, the tubes 

 of the calyx longer and the flower buds thinner. At the time of 

 flowering they resembled the hybrids of Oe. LamarckianaxOe. biennis 

 more than the pure Oe. biennis. In all these points the influence of 

 the pistil parent was evident and the type could be described as 

 intermediate between the two parents with a strong predominance 

 of the pollen parent. The mid veins of the leaves were reddish as 

 in Oe. biennis, and on this ground we may designate the type by the 

 same name as in the case of Oe. Hookeri, and call it, for convenience, 

 rubiennis. 



I self-fertilized four specimens, cultivated their offspring in 120 

 specimens for each of them and counted these in July, at the be- 

 ginning of the flowering period, when the differences between the 

 two main types were sharp and clear. About one-half of the plants 

 had made stems but the others were still in the condition of rosettes. 

 In both groups, however, the sorting out of the types left almost 

 no dubious specimens. The majority of the plants were franciscana- 

 like, as described by Davis, whereas the remainder resembled the 

 first generation. I found: 



Table 11 

 Second generation of Oe. franciscana x Oe. biennis. 



