MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 257 



Oe. biennis Chicago x Oe. suaveolens. The cross of 1914 yielded 

 in the next year 80 offspring, all of which became annual and 

 reached a height of nearly one meter. Half of them were left to 

 flower. They were a uniform group, combining the characters of 

 both parents. The main traits were those of Oe. biennis Chicago, 

 but the height was less, the leaves narrower and the spikes less 

 densely covered by the bracts. The flowers were of an intermediate 

 size, having almost the size of those of Oe. biennis Chicago, and the 

 internodes of the spikes were also much smaller than in the female 

 parent. They were observed till the end of August. 



The seeds of a self-fertilized specimen of 1915 were sown in 1916, 

 the progeny embraced 70 flowering individuals which were uniform 

 and exactly like the previous generation. No trace of dimorphy 

 could be discovered. 



Oe. suaveolens x Oe. biennis Chicago. -- Cross of 1913, of which 

 60 offspring were cultivated in 1914. One half was left to flower 

 and reached a height of 2% meters at the end of August. They 

 were uniform, resembling the pollen parent, but with white mid- 

 veins in their leaves and relatively large flowers. Length of petals 

 3 cm. The marks of Oe. suaveolens did not come out strongly in the 

 hybrid, but a compaiison with Oe. biennis x biennis Chicago and 

 Oe. syrticola x biennis Chicago showed the differences in the in- 

 fluence of the female parent clearly. Especially the flower buds re- 

 sembled those of Oe. suaveolens. No second generation has been studied. 



Oe. (suaveolens x biennis) x Oe (biennis x suaveolens) — The 

 cross was made in 1915 between two of the hybrids described above, 

 and a specimen of the biennis type of the first group was chosen 

 as female parent. From the rules for the double reciprocal hybrids 

 of Oe. biennis, it was to be expected that most of the characters 

 of this species would disappear, viz., all those which are different 

 in their female from their male gametes. Only those marks, which 

 are the same for both sexes, would be repeated in the double reci- 

 procal hybrid. 



1 cultivated a group of 70 specimens, almost all of which flowered. 

 They were intermediate between the pollen parent (Oe. biennis x 

 suaveolens) and the pure species Oe. suaveolens, showing the disap- 

 pearance of nearly all the marks of the biennis type. In July, when 

 they flowered, the resemblance with Oe. suaveolens increased; the 

 plants were almost as high and as richly branched as these, with 

 their large flowers. The petals were 2.5—3 cm. long and broad 

 enough to cover one another along their margins. 



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