Page:Popular Science Monthly Volume 62.djvu/500

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

The latas were, as we have seen, obtained partly from seed collected 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 Lamarkiana, 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 phenomenon. 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 difficulties. 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 ancestors 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. Lamarkiana, 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 flowers, 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