244 MUTATIONS OF OENOTHERA SUAVEOLENS DESF. 



so called pure lines. They produced essentially the same mutants. 

 As soon as this fact was ascertained one of them was abandoned 

 and thus reduced to the rank of a control experiment. The other 

 pure race yielded the results to be described here. 



The original station of my Oe. suaveolens is an old orchard along 

 the road from Melun to Fontainebleau situated near the cemetery of 

 Samois (Opera VI, p. 568). The seeds for my cultures were saved 

 there by Prof. L. Blaringhem in 1912. When I visited the place 

 with him in October 1913 we found two or three hundred speci- 

 mens still flowering and with ripe seeds. They all belonged to the 

 same form; especially no biennis and no hybrids were observed, as 

 is so often the case in the open fields of the same neighborhood. 

 The seeds of 1912 yielded only a small culture in my garden in 

 1913, embracing 22 plants, of which 7 flowered. They were pure 

 Oe. suaveolens without mutants and without visible differences. 

 This was the more striking, since seeds from other stations yielded 

 some aberrant individuals, as will be seen later on. I chose one 

 of the most vigorous plants for starting my race, pollinated its 

 flowers myself in small bags and saved the seeds separately. A 

 second plant was dealt with after the same manner in order to have 

 a control, as has already been said. I cultivated three succeeding 

 generations from the main plant in 1914, 1915 and 1916, follow ng 

 always the same principles 1 ). 



In 1914 the seeds of the initial plant of my race yielded only one 

 mutant, an Oe. jaculatrix, among 51 specimens. Besides this one, 

 four typical individuals were self-fertilized and yielded the seeds 

 for the larger cultures of 1915 in which almost all my mutants 

 arose. In this race one-half of the seeds are empty, as in Oe. La- 

 marckiana. This character, however, does not seem to have any 

 influence on the mutability, nor on the result of the crosses (Opera 

 VII, p. 109). For all the cultures mentioned in this article the seeds 

 have been soaked in water under a pressure of eight atmospheres 

 in order to secure complete germination. 



The fourth generation of the pure line, in 1916, was once more a 

 small one with only 109 specimens, of which 59 flowered. It con- 

 tained four mutants, viz., 3 lutescens and one jaculattix. Second 

 generations have been grown for all the types of the mutants, with 

 the exception of apetala, which arose only in 1916 and began to 



*) These have been used in all my cultures of Oenothera since 1895, and en- 

 dowed later on by Johannsen with the appropriate though poetical name of 

 pure lines. 



