One feature of the _Oenotheras_ is very curious. Not only _Lamarckiana_, but all the allied species so far as I am aware, have a considerable proportion of bad and shrivelled pollen grains. This is undoubtedly true of species living in the wild state as well as of those in cultivation. I have had opportunities of verifying this for myself in the United States. No one looking at the pollen of an _Oenothera_ would doubt that it was taken from some hybrid plant exhibiting partial sterility. On the other hand, it is difficult to suppose that numbers, perhaps all, of the "species" of the genus are really hybrids, and many of them breed substantially true. I regard this constant presence of bad pollen grains as an indication that the genetic physiology of _Oenothera_ is in some way abnormal, and as we shall presently see, there are several other signs which point in the same direction. Discussion of the whole series of phenomena is rendered exceedingly difficult first, by reason of the actual nature of the material. The characteristics of many of the types which de Vries has named are evasive. A few of these types, for instance, _gigas_, _nanella_, _albida_, _brevistylis_, and perhaps a few more are evidently clear enough, but we have as yet no figures and descriptions precise enough to enable a reader to appreciate exactly the peculiarities of the vast number of forms which have now to be considered in any attempt to gain a comprehensive view of the whole mass of facts. It is also not in dispute that the forms are susceptible of great variations due simply to soil and cultural influences. The fact that no Mendelian analysis has yet been found applicable to this group of _Oenotheras_ as a whole is perhaps largely due to the fact that until recently such analysis has not been seriously attempted. Following the system which he had adopted before the rediscovery of Mendelism, or at all events, before the development of that method of analysis, de Vries has freely applied _names_ to special combinations of characters and has scarcely ever instituted a factorial analysis. Before we can get much further this must be attempted. It may fail, but we must know exactly where and how this failure comes about. There are several indications that such a recognition of factorial characters, could be carried some way. For example, the height, the size of the flowers, the crinkling of the leaves, the brittleness of the stems, perhaps even the red stripes on stems and fruits, and many more, are all characters which may or may not depend on distinct factors, but if such characters are really transmitted in unresolved groups, the limitations of those groups should be carefully determined. The free use of names for the several forms, rather than for the characters, has greatly contributed to deepen the obscurity which veils the whole subject.