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THE AMEBIC AX XATURALIST [Vol. XLVI 



of antliocyan. The rosettes resembled those of Lamarck- 

 iana very closely in their morphology, much more closely 

 than those of my earlier hybrids (see Davis, '11, Figs. 9 

 and 12), as would be expected from a cross involving the 

 broader-leaved biotype biennis D. 



Continued experience with the rosettes of (Enothera 

 has shown that there is a greater range of variation 

 among the F x hybrids of the species crosses than might 

 be expected by those whose studies have been upon 

 hybrids of closely related races. It has always been pos- 

 sible to arrange the mature rosettes of a large culture in 

 a series with a small group at each end that differ and 

 incline towards the two parents. It is my method to set 

 out the rosettes in this order and generally the rosettes 

 at the ends will develop into mature plants exhibiting a 

 similar degree of divergence from the mass of the cul- 

 ture. But this is by no means a fixed rule and rosettes 

 giving promise of a certain line of development may 

 grow into mature plants of an unexpected type. I have 

 emphasized the divergence between the rosettes at the 

 extremes of an F x generation, but it must not be supposed 

 that these plants constitute classes. On the contrary, in 

 large cultures they apparently range insensibly into the 

 mass. 



A comparison of the parents of this cross, grandiflora 

 B (see Davis, '11, pp. 205-207) and biennis D described 

 above, will show that they differ chiefly in the relative 

 form, size and proportions of their organs, and their 

 characteristics would be expected to be present in the F x 

 hybrids in blended relations, as is the fact. The only 

 character observed that might be sharply contrasted as 

 present or absent in these parents is the coloration of the 

 papillate glands which in biennis D are red on green 

 stems and .ovaries, and in grandiflora D are uncolored, 

 i. e., lack the red. The hybrids of the F 1 generation 

 naturally might be expected to exhibit either the presence 

 or absence of the red coloration in these glands as one or 

 the other condition might be dominant. 



