i9i6] DeVRIES— DIMORPHIC MUTANTS 255 



marckiana mut. nanella and none of those of 0. cana. This has 

 been the case in some of the other pedigree cultures of this type, 

 but it should be remarked that in other cases the char xters of 

 0. cana may combine with the dwarf stature. Such dwarfs have 

 the narrow gray fohage and are easily distinguished from typical 

 0. nanella specimens. 



The self-fertiHzed seeds of the cana individuals split in both 

 generations into cana and Lamarckiana, just as 0. scintillans splits 

 into scintillans and Lamarckiana. The proportions 16-24-34 

 per cent with a mean of 25 per cent seem to indicate a spHtting 

 into nearly equal parts, with a loss on the side of the weaker form. 

 The same deviation from equality will be seen in almost all the fig- 

 ures of this article, and the same explanation must be considered 

 as applying to all of them. It is almost always the new type which 

 is in the minority." 



The seeds of the Lamarckiana-]ike individuals do not give rise 

 to a sphtting of this kind, keeping true to their parent -form. The 

 same fact recurs in all the pedigrees to be mentioned later on, and 

 for all the new dimorphic types. It may be taken to be the rule, 

 therefore, although the trials have been only one or two in each 

 instance. It agrees fully with the behavior of the analogous split- 

 ting products of 0. scintillans. 



0. cana from lata nos. 2 and 3. — In a culture of about 600 

 seedlings of O. lata, 4 mutants of the cana type arose in 1908. 

 The lata strains had been derived from some annual mutants which 

 had been produced by my 0. Lamarckiana in 1905, and described 

 in my Gruppenweise Artbildung (p. 247). From these mutants 

 a second generation was cultivated in 1907, and fertihzed by the 

 pollen of Lamarckiana-Uke individuals of the same culture. Their 

 seeds yielded the two cana mutants to be described here, and two 

 others, from the seed of which only]one'generation has been studied. 



The pedigree of mutant no. 2 is given below: 

 1908 Mutant Mutant 



igi2 Second generation 35 per cent cana ~-Laniarckiana 



igi3 Third generation 15 per cent cana ^Lamarckiana Lamarckiana 



' Excepting the case of biennials; see later statement. 



