1917] DeVRIES— OENOTHERA 3 



about 



At the time when the 



seedlings must be planted in larger boxes, their marks are fully 

 reliable, even in hybrid mixtures. Their leaves are narrow and 

 a pale yellowish green, whereas those of 0. Lamarckiana are broad 

 and a deeper green. As the rosettes increase the number and the 



typ 



some weeks more 



are ripe for transplanting into the garden, O. blandina is clearly 

 a type of its own and can easily be counted off in the mixtures. 

 In May the rosettes of O. Lamarckiana gradually become very stout, 

 but those of 0. blandina remain slender. The leaves are so narrow 

 as not to touch each other regularly nor to cover the ground 

 between them. They resemble those of O. rubrinervis, but lack 

 the brittleness, the typical bending of the petiole and blade, and the 

 specific color of this form. Moreover, they show a high degree of 

 fluctuating variability in their color. This is always gray, on 

 account of the hairiness of the surface, but it varies between a 

 normal green and a more or less pale and yellowish tinge. The 

 paler they are, the poorer they are in chlorophyll, and therefore 

 the palest individuals soon begin to show a slower growth. They 

 stay behind the others the more, the paler they are. These differ- 

 ences increase if the culture is densely planted, and even at the time 

 of flowering the paler individuals may be seen to be much weaker 

 and shorter than the others. In ordinary cultures, however, when 

 the plants are at a distance of 20 cm. or more from their next 

 neighbors, and grown in a well manured soil, these differences 

 gradually disappear and are no longer visible when the first flowers 

 open. In order to fertilize pale individuals beside the green ones, 

 I had to mark them in early youth. From the self -fertilized seeds 

 of the green ones the seedlings are on the average less pale than 

 those of the paler parents, but the difference, although obvious and 

 unmistakable on the beds in springtime, soon disappears as the 

 summer begins. From time to time there is even a partial vari- 

 ability, such as, for instance, a green branch on a stem with pale 

 leaves. This shows that there is no racial difference between the 

 green individuals and the pale ones, even as in the cases of Oeno- 

 thera (Lamar ckianaXatrovir ens) gracilis and of O. (Lamar ckianaX 



