OENOTHERA GRANDIFLORA AIT. 



211 



laeta. In August the height was 1.50—1.80 m., and the resemblance 

 of the two types to 0. (biennis x Lamarckiana) laeta and velutina 

 was very striking, although the plants, as would be expected, were 

 less stout. The flower buds of the velutina were thick, as usual, 

 measuring 9 x 25 mm., as compared with 7 x 30 mm. for those of 

 laeta. The free tips of the calyx were distant in the first, but pressed 

 against one another in the second hybrid. The incision at the top 



Table III 

 Twin hybrids of O. grandiflora 



Cross 



First generation 



Second generation 



Percen- 

 tage 

 laeta 



Percen- 

 tage 

 velutina 



Percentage 

 laeta 



Percentage 

 velutina 



A. aeta and velutina 



* The third generation continued uniform. 



of the petals was deep in the velutina, but slight in the laeta. The 

 first were more hairy in all parts, especially on the flower buds 

 and the younger parts of the axis of the spike. Their leaves were 

 narrow, kennel-shaped, and smooth. The apex of the spike above 

 the flowers was more densely covered by flower buds, but that 

 of the laeta more loose, as shown in fig. 4. In all these respects the 

 differences were the same as those between the twins of 0. biennisx 

 Lamarckiana. 



I fertilized a laeta and a velutina and had in 1916 a progeny of 

 63 and 70 plants respectively, most of which flowered. The off- 



