MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 249 



On one of the stations near Fontainebleau on the border of the 

 forest and at a large distance from that which yielded my race, I 

 observed in 1913 about a dozen of specimens with such pale flowers. 

 One of them had ripe capsules and their seeds yielded in 1914 a 

 culture of 120 flowering plants, of which 53 were sulfurea whereas 

 the remaining 67 had the same bright yellow color as the species 

 itself. From this fact we may conclude that the sulfurea character 

 was repeated after self-fertilization but was recessive to the bright 

 yellow of the surrounding individuals. Since this behavior is ana- 

 logous to that of Oe. biennis sulfurea, I have repeated the experiment 

 with my own mutant. 



This arose in 1915 in the second generation of my pure race from 

 seeds of 1913, in a culture of 1011 flowering specimens from the 

 seeds of the four self-fertilized individuals of 1914. The proportion 

 is seen to be 0.1 percent, whereas Oe. biennis sulfurea was produced 

 in my cultures in about 0.3 percent (Opera VII, p. 20). I fertilized 

 some flowers with their own pollen in bags and brought their pollen 

 partly on castrated flowers of a typical specimen of my race, but 

 had no opportunity for making the reciprocal cross. But since the 

 plant flowered among over one thousand normal specimens, I could 

 be confident that its previous flowers which had been visited by 

 bees would be partly self-fertilized and partly crossed with these, 

 and so I saved their seeds. 



The self-fertilized seeds yielded 25 plants, the flowers of which 

 were all of the same pale yellow as in the parent. The cross Oe. 

 suaveolens x suaveolens mut. sulfurea yielded 52 flowering plants, 

 all of wiiich had the pale color of the mutant. There were two mutants 

 fastigiata and one mutant lutescens, which, however, did not flower. 

 The seeds from the open-pollinated flowers yielded 54 flowering 

 individuals. Among these 46 were suaveolens mut. sulfurea like the 

 parent, 6 were suaveolens with the bright flowers of the species and 

 two were hybrids of the type of suaveolens x Lamarckiana, and 

 with bright yellow flowers. Evidently the first group was due to 

 self-fertilization, the second to vicinism or to the fecundation by 

 neighbors, and the third to Lamarckiana pollen brought by insects 

 from a distance. They strengthen the conclusion that the cross 

 Oe. suaveolens mut. sulfurea x Oe. suaveolens must give the flower 

 color of the latter species. 



Thus we have, in regard to the color of the petals: 



Oe. suaveolens x Oe. suaveolens mut. sulfurea = sulfurea-, Oe. 

 suaveolens mut. sulfurea x Oe. suaveolens = suaveolens. — All other 



