326 Origin of Each Species Considered Separately. 



been described in § 3 (p. 227). It was evident that it 

 was a constant species directly its seeds germinated. As 



Fig. 65. Seedlings of Oenothera Lamarckiana (L) and 

 O. gigas (G). c, the cotyledons. Magnitied; the natural 

 size shown in the middle. 



soon as they have acquired their first and second leaves 

 the seedlings can be distinguished from those of the 



parent species with perfect 

 ease (Figure 65). Their 

 leaves are not only broader 

 but more or less markedly 

 cordate at their base. The 

 latter character is gradu- 

 ally lost in the succeeding 

 leaves but the broader base 

 persists for some time 

 longer as a convenient 

 mark of identification (Fig. 

 66). 



This character made it 

 possible for me to demon- 

 strate the constancy of the 

 new species in the second, third and fourth generations 

 (1897, 1899, 1900) without having to grow more than 

 20 to 40 plants to maturity. 



Fig. 66. Older seedlings of O. 

 Lamarckiana (L) and O. gi^as 

 (G). c, cotyledons, red. to "A- 



