We next meet the remarkable fact that these two forms, _laeta_ and _velutina_ breed true to their respective types, and do not reproduce the parent-types among their offspring resulting from self-fertilisation. This statement must be qualified in two respects. When _muricata_ [M] is fertilised by _brevistylis_ the forms _laeta_ and _velutina_ are produced, but each of them subsequently throws the short-styled form as a recessive (de Vries, 1907, p. 406). It may be remembered that de Vries's previous publications had already shown that the short style of _brevistylis_, one of the _Lamarckiana_ "mutants," behaves as a recessive habitually (_Mutationstheorie_, II, p. 178, etc.). Also when _nanella_, the dwarf "mutant" of _Lamarckiana_ is used as male on _muricata_ as female, _laeta_ and _velutina_ are produced, but one only of these, namely, _velutina_, subsequently throws dwarfs on self-fertilisation. The dwarfs thus thrown are said to form about 50 per cent. of the families in which they occur (de Vries, 1908, p. 668). The fact that the two forms, _laeta_ and _velutina_, are produced by many matings in which _Lamarckiana_ and its mutant _rubrinervis_ are used as males is confirmed abundantly by Honing, who has carried out extensive researches on the subject. After carefully reading his paper, I have failed to understand the main purport of the argument respecting the "double nature" of _Lamarckiana_ which he founds on these results, but I gather that in some way _laeta_ is shown to partake especially of the nature of _Lamarckiana_, while _velutina_ is a form of _rubrinervis_. The paper contains many records which will be of value in subsequent analysis of these forms. Before considering the possible meaning of these facts we must have in our minds the next and most novel of the recent extensions of knowledge as to the genetic properties of the _Oenotheras_. In the previous statement we have been concerned with the results of using either _Lamarckiana_ itself or one of its "mutants" _rubrinervis_, _brevistylis_, or _nanella_ as male, on one of the species _biennis_ or _muricata_. The new experiments relate to crosses between the two species _biennis_ and _muricata_ themselves. De Vries found: 1. That the reciprocal hybrids from these two species differed, _biennis_ × _muricata_ producing one type of F_{1} and _muricata_ × _biennis_ producing another. Each F_{1} resembled the father more than the mother. 2. That each of the hybrids so produced breeds true on self-fertilisation. 3. That if we speak of the hybrid from _biennis_ × _muricata_ as _BM_ and of the reciprocal as _MB_, then _BM_ × _MB_ gives exclusively offspring of _biennis_ type but that _MB_ × _BM_ gives exclusively offspring of _muricata_ type. Evidently, apart from all controversy as to the significance of the "mutants" of _Lamarckiana_, we have here a series of observations of the first importance.