6 



BOTANICAL GAZETTE 



[JANUARY 



The laeta and the velutina were of the description already given. 

 I sowed the self -fertilized seed of 1906 in 1907 and 1908 and had 

 four lots of the second generation. The lots of the first included 

 69 and 139 individuals, all of which were laeta; the sowings of the 

 other strain extended over 38 and 158 samples, all of which were 

 velutina. Both of the twins thus complied with the rule of constancy 

 in the second generation. From the lots of 1907 I cultivated in 1908 

 a third generation comprising 70 children of laeta and 90 of velutina; 

 both lots were once more uniform and similar to their parents. 



The lata individuals of this cross were almost similar to those of 

 O. lata itself. However, they had the smaller flowers of O. biennis, 

 with the self-fertilizing position of the stigma, and the long lobes of 

 the father. Their flower buds were intermediate between those of 

 the two parents. In 1906 and 1907 the anthers seemed wholly 

 barren; but in 1908, during the very warm last days of July, they 

 yielded some pollen, which was used partly for self-fertilization, 

 partly for crosses. 



Hookeri 



most 



crosses with O. lata, since its lata hybrids are almost as rich in pollen 

 as any other evening primrose. This enabled me to study the second 

 generation of the lata, which, in contrast to that of the laeta and the 



elutina 



repeats the splitting. The yield of the pollen was small in 

 the unfavorable summer of 1907, but large during the hot days of 

 July and August, 1908. 



I have made this cross twice, in 1905 and 1907; the parents were 

 annual specimens. I had the following results in the first generation : 



Year 



J 9Q7 



1908 



1908 



Total 



Seed of 



Number of 

 specimens 



Percentage 

 laeta 



J 9°5 



I905 

 1907 



Percentage 

 velutina 



51 



229 



72 



53 

 45 

 49 



352 



47 



39 



47 



28 



42 



Percentage 

 lata 



8 



8 



22 



11 



Here also the laeta and 



from 



cross with Lamarckiana. I sowed some self -fertilized seed of the 

 velutina of 1906, partly in 1907 and partly in 1908, and cultivated 



