Secondly the instability seems to be a constant quality, although the words themselves are at first sight, contradictory. I mean to convey the conception that the degree of instability remains unchanged during successive generations. This is a very curious fact, and strongly reminds us of the hereditary conditions of striped-flower varieties. But, on the contrary, the atavists, which are here the individuals with the stature and the characteristics of the _lamarckiana_, have become _lamarckiana_s in their hereditary qualities, too. If their seed is saved and sown, their progeny does not contain any _scintillans_, or at least no more than might arise by ordinary mutations. One other inconstant new species is to be noted, but as it was very rare both in the field and in my cultures, and as it was difficult of cultivation, little can as yet be said about it. It is the _Oenothera elliptica_, with narrow elliptical leaves and also with elliptical petals. It repeats [546] its type only in a very small proportion of its seed. All in all we thus have a group of a dozen new types, springing from an original form in one restricted locality, and seen to grow there, or arising in the garden from seeds collected from the original locality. Without any doubt the germs of the new types are fully developed within the seed, ready to be evolved at the time of germination. More favorable conditions in the field would no doubt allow all of the described new species to unfold their attributes there, and to come into competition with each other and with the common parents. But obviously this is only of secondary importance, and has no influence on the fact that a number of new types, analogous to the older swarms of _Draba_, _Viola_ and of many other polymorphous species, have been seen to arise directly in the wild state. [547] LECTURE XIX EXPERIMENTAL PEDIGREE-CULTURES The observation of the production of mutants in the field at Hilversum, and the subsequent cultivation of the new types in the garden at Amsterdam, gives ample proof of the mutability of plants. Furthermore it furnishes an analogy with the hypothetical origin of the swarms of species of _Draba_ and _Viola_. Last but not least important it affords material for a complete systematic and morphologic study of the newly arisen group of forms.