VOLUME LXVII NUMBER 



NtW Vf>RK 

 THE 8M?TArMCAL 



QaKOBN 



Botanical Gazette 



JANUARY igig 



OENOTHERA RUBRINERVIS, A H.AXF MUTANT 



Hugo DeVries 



In the spring of 19 13 in a culture of Oenothera ruhrinervis I 

 noticed some young plants, the leaves of which were a little broader 

 than those of the other rosettes. Although the difference was very 

 small, I planted them separately and saw that the deviation did 

 not increase until the time of flowering. The spikes, however, gave 

 proof that the aberrant specimens constituted a type of their own, 

 since the bracts repeated the marks of the primordial leaves, being 

 broader and more flattened than in ordinary ruhrinervis. There 

 were 7 specimens of the new form among a culture of 25 plants, all 

 of which flowered in August. This indicates a percentage of about 

 30. In the following year the seeds of the new form gave a uniform 

 progeny, whereas those of the normal specimens repeated the split- 

 ting. Thereupon I studied their seeds and found that about one- 

 fourth of those of O. ruhrinervis were empty, but almost every seed 

 of the new t^pe contained a living embryo. On account of this very 

 small but constant difference the new form was designated as mut. 

 deserens} Evidently it might have escaped observation in previous 

 years, the individuals simply being taken for weaker specimens of 

 the type. I studied the progeny of as many self -fertilized specimens 

 of O. ruhrinervis as were available, therefore, and found the new 

 type among all of them, and as a rule in correspondingly high num- 

 co bers. Different strains of ruhrinervis yielded the same result. 



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CD 



' Zeitschr. f. Ind. Abst. 16: 262. 1916. 



