KNOWLEDGE OF THE MUTATING OENOTHERAS. 47 



These cultures also by showing that, in addition to 0. grandifloj^a, O. Lamar chiana, 

 and its mutants as known from DeVries's experiments, a host of other forms occur in a 

 freely interbreeding population, raise the question as to the origin of the latter forms, 

 and the limits and relations between hybridization and mutation. The first step in 

 answ^ering that question is taken by isolating the many races and learning their 

 characters. The next step is to recombine them in various ways and determine the 

 results of those recombinations or by independent syntheses to build up hybrid races 

 haying the same characters. By such means we may expect ultimately to understand 

 the relation between hybridization and mutation phenomena. 



Pinally, it is important to note certain facts regarding the history of this colony of 

 Oenotheras. It must perhaps always remain uncertain whether the O. Lamarchiana in 

 this colony was transported as such from the other side of the Atlantic, or whether it 

 originated in the colony as a result of crossing. I have pointed out that in the latter 



would have had an equal chance of orig 



gion of Virg 



both 0. biennis and O. grandiflora, the only forms which could have given rise to it, 

 were formerly wild. In any case, the important fact, from an evolutionary point of 

 view, is that O. Lamarchiana and its derivatives, such as 0. ruhrinervis^ are now the 

 dominant feature of this Oenothera colony. Whether or not they have originated in 

 that colony, they are the forms which will provide most of its future population, and, 

 therefore, determine any future evolution it may undergo. If 0. Lamarchiana has 

 originated there as a hybrid, then it has largely overcome its parent species in the 

 struggle for existence, and its descendants will be the survivors for the next 

 evolutionary step. 



(B) Cultures feom Botat^ical Gardens. 



I have obtained seeds of various Oenothera species from nearly all the Botanical 



J 



Gardens in Europe. A number of these cultures have contained distinct surprises. 

 I have already mentioned certain ones in other connections, but a few more will be 

 added here. Of course, the names under which seeds are received cannot always be 

 relied upon. I have received 0. Lamiarchiana several times under the names 0. biennis 

 or O. biennis grandljlora. Por instance, seeds from the Botanical Garden at Kolosvar, 

 Hungary, under the name O. biennis g7^andiflora were found to be nearer 0. Lamarchiana 

 than any other species, though not typical of its mean condition. Again, seeds from 

 the same garden under the name O. erythrosepala^ Barb., developed 0. Lamarchiana and 

 one typical 0. lata mutant. 



A lot of seeds of O. suaveolens, Desf. (=0. grandifiord), from Nantes Botanical Garden 

 yielded nearly 200 plants, which showed a great range of variability with every evidence 

 of previous crossing. Many of the rosettes closely resembled 0. Lamarchiana, while 

 some were very similar to 0. rubrinervis. Among other aberrant types, there were 

 one dwarf and two with short styles. The flower dimensions in one of the latter were 

 as follows : ovary 15-17 mm., hypanthium i7-51 mm., petals 40-i2 mm. long. The 

 style, however, was very short so that the stigma was below the anthers. The sepals 

 were reddish, and the plant somewhat resembled a brecisli/lis form of 0. rubrinervis. All 



