igig] 



DeVRIES— OENOTHERA RUBRINERVIS 



II 



The results coincide with the previous ones as nearly as might 

 be expected. The types of the twins were the same as those in the 

 older cultures. 



For these twins I have determined the amount of empty grains, 

 self-fertilizing two specimens of each of them in August 191 6 and 

 counting out 100 seeds for each parent. 



Percentage of germs in seeds of laela and vehitina 



As in other cases, the seeds of the laeta hardly contain any empty 

 grains, whereas those of the velutina are often badly developed. 



My task was now to repeat these crosses, substituting O. mut. 

 deserens and 0. mut. velutina for O. rubrinervis. The latter group 

 of crosses have already been described elsewhere;^ they yielded pure 

 cultures of velutina which in every case were exactly like the velutina 

 of the corresponding cross with 0. Lamarckiana. The crosses with 

 0. deserens were made in 191 5 and their progeny studied in 191 6; 

 it was in every case wholly uniform. 



Crosses of 0. mut. deserens 



About one-half of each culture flowered and developed their 

 fruits. For each culture a control parcel was cultivated with the 

 laeta from the corresponding cross with O. Lamarckiana, and they 

 were compared during all the time of their development. I could 



^ Kreuzungen von Oenothera Lamarckiana mut. velutina. Zeitschr. f. Ind. Abst. 

 17:1917. 



