De Vries found, as is well known, that _Oenothera Lamarckiana_ gives off plants unlike itself. These mutational forms are of several distinct and recognizable types which recur, and several of them breed true from their first appearance. The obvious difficulty, which in my judgment should make us unwilling at present to accept these occurrences as proof of the genesis of new species by mutation, is that we have as yet no certainty that the appearance of the new forms is not an effect of the recombination of factors, such as is to be seen in so many generations of plants derived from a cross involving many genetic elements. The first question is what is _Oenothera Lamarckiana_? Is it itself a plant of hybrid origin? To this fundamental question no satisfactory answer has yet been given. All attempts to find it as a wild plant in America have failed. It existed in Europe in the latter half of the eighteenth century. Whence it came is still uncertain, but the view that it came into existence in Europe and perhaps in Paris, seems on the whole the most probable. The question has been debated by Macdougal, Gates, and Davis. From historical sources there is little expectation of further light. Those who favour the notion of a hybrid origin look on _Oenothera biennis_ as one of the putative parents. It has been conjectured that a species called _grandiflora_ lately re-discovered on the Alabama river was the other parent. Experiments have been instituted by Davis to discover whether _Lamarckiana_ can be made artificially by crossing these two species. The results so far have shown that while plants approximating in various respects to _Lamarckiana_ have thus been produced, none agree exactly with that form. Davis, to whom reference should be made for a full account of the present state of the enquiry, points out that there are many strains of _biennis_ in existence and that it is by no means impossible that by using others of these strains a still closer approximation can be made. None of Davis's artificial productions as yet breed at all true, as _Lamarckiana_ on the whole does. In such a case, however, where several characters are involved, this is perhaps hardly to be expected.