204 Davis. 



stroug the patroclinoiis and matrocliuoiis tendencies. With respect to 

 the behavior of anthocyan coloration a critical stud}- of the hybrids 

 has been puzzling since it is extremely difficult, with this character 

 exhibiting wide fluctuations, to judge of its expression in the hybrids, 

 whether absolutely dominant or whether present in a modified intensity 

 that would signify a blend. The behavior can I think be most satis- 

 factorily studied in the coloration of the papillae upon the stem, as 

 presented in the hybrids of biennis and franciscana, and I shall hope 

 to give it further attention. 



It is, however, noteworthy that patrocliny and matrocliuy are very 

 striking phenomena in these hybrids of Oenothera and demand an ex- 

 planation which is not j-et evident. We have seen that merogony 

 (GOLDSCiDvnDT '12) will not serve as an explanation for the reason that 

 the products of the crosses are undoubtedly true hybrids as shown by 

 a critical examination of their characters and because the cytological 

 data so far at hand (Rekn'ER '13) clearly point to a normal process of 

 fei'tilization. If any of the characters of the hybrids exactly duplicated 

 those of either parent we might tliink them examples of sex-limited in- 

 heritance, but the evidence is not convincing that exact duplication is 

 ever attained even in the most extreme cases of patrocliny. 



There seems at present to be left to us only that vague concep- 

 tion of prepotency which is really no explanation although it serves at 

 least to name the phenomenon. There is in these hybrids a strong prepo- 

 tency of the male parent over the female although this does not affect 

 aU of the characters for we have noted conspicuous nuxtroclinous ten- 

 dencies most striking^ illustrated in the inflorescence of the crosses 

 between biennis and muricata. An important feature of this prepotency 

 lies in the fact that it is not a peculiarity of certain individuals of the 

 same sex, but that it is a prepotency of one species over another with 

 respect to the characters concerned. Cytological investigations may give 

 us the explanation of the problems involved and the results of sucli 

 studies wül be awaited with great interest. 



