494 POPULAR SCIENCE MONTHLY. 



until at last there appeared approximately one new form on every 100 

 individuals. 



The latas were, as we have seen, obtained partly from seed col- 

 lected from wild plants and partly from seed yielded by wild plants 

 transported to and cultivated in the botanic garden. Yet they agreed 

 entirely in all respects, forming but a single well-defined type. Later 

 in 1889 and in 1894, I also found them in the original locality.* In 

 my garden they made their appearance nearly every year. Each lata- 

 plant which, without similar ancestors, originated from the Oenothera 

 Lamarchiana, bears always exactly the same characters; one can always 

 recognize it shortly after germination, and predict at the time all 

 characters which it will exhibit later on. The same is true for the 

 dwarfs, for the shiny forms, etc. 



Once the certainty obtained of having found a mutating plant, I 

 of course applied myself as closely as possible to a study of this phe- 

 nomenon. Naturally this was at first connected with great difficulties, 

 especially because I did not have an exact idea of what I was to look 

 for. It was only in 1895 that I succeeded in surmounting these diffi- 

 culties. I had by that time realized how small were the differences to 

 which I had to pay attention, and that these differences, at least for the 

 greater part, are apparent in the earliest stages of development. I 

 therefore sowed on a large scale, reviewed my plants nearly daily, and 

 changed each clearly deviating form to another bed, where it was given 

 plenty of room and tended with great care. 



That year I obtained about 14,000 plants from seed. Dwarfs and 

 roundheads made their appearance in large numbers, 60 of the former 

 and 73 of the latter. Their parents had been ordinary Lamarckianas, 

 carefully pollinated with each other's pollen, as had been their ances- 

 tors of the last two generations and therefore of pure descent, as were 

 probably all their ancestors of the original locality. The shiny form 

 also made its appearance, again in but a single specimen. Besides 

 there appeared five entirely new forms; three of these were separated 

 as rosettes, one only showed itself to be a new form, when flowering, 

 and the other only during the next year after hibernating. 



The last two were rare, the one, O. leptocarpa, appeared in two 

 specimens, the other, O. gigas, in a single individual. Both are at 

 present constant to seed, absolutely unchangeable. The former is not 

 beautiful, but ranker and taller than O. Lamarchiana, and flowers 

 later in the season. Oenothera gigas, on the other hand, is a splendid, 

 exceedingly robust plant, which, with a rich crown of very large flow- 

 ers, easily excels the mother species. 



The three others I denoted as 'red-nerved,' O. rubrinervis, 'white,' 

 O. albida, and O. oblonga. They appeared respectively in 8, 15 and 



* Likewise this year [1902]. 



