V 



2>2>2 Origin of Each Species Considered Separately. 



all the cultures irrespective of whether they contained it 

 or not. On tlie latter estimate the number would prob- 

 ably sink to 0.1 %, if not lower. 



It has already been stated that 0. nibrinervis can be 

 recognized as quite a young plant. Pans or boxes con- 

 taining nothing but 0. nibrinervis can be identified very 



A' 



.A 



G'P^ 



Fig. 68. Seedlings of Oenothera ruhrinervis at various 

 ages ; c, the cotyledons ; A, with the first two leaves at 

 the beginning of May; A' , the natural size of the same. 

 B, 14 days older. C , Rosette, towards the end of June, 

 just before transplanting, from a pan in which the seed- 

 lings were growing very close. Compare Fig. 64, p. 325 

 and Figs. 65 and 66, p. 326. 



early, a good deal earlier than mutants standing amongst 

 other species (Fig. 48 on page 280). But in these the 

 narrow leaves with their red veins and gray felt-like 

 surface, the almost complete absence of crumples and the 

 brittleness especially of the stalk, clearly distinguish this 

 form from 0. Lamar ckiana and the rest, (Compare 



