No. 547] GENETICAL STUDIES ON (EN OTHER A 397 



which the representatives of Class I can be distinguished 

 in the rosette condition ; they certainly do not constitute 

 either of the small groups of rosettes that are more 

 like one or the other of the two parents. 



The differentiation of these two classes of hybrids in 

 an f\ generation appears to be similar to the phenomenon 

 of "twin hybrids" reported by De Vries ('07) although 

 the contrasted characters are somewhat different. The 

 behavior is most interesting, especially in its relation to 

 the results expected in F, generations according to gen- 



eral experience and Mendelian laws. We should have 

 expected the red coloration of the papillate glands of the 

 biennis parent to be either dominant or recessive to the 

 uncolored glands of the grandiflora parent ; as a matter 



