Genetical Studies on Oenothera. V. 



171 



seed brouji'ht from Europe. It is a plant clearly distinct from the forms 

 described as biennia in the American systematic manuals as all American 

 workers on Oenothera in the experimental gardens know. Bahtlett ("13) 

 has discussed the characters of this plant and given strong reasons wh,y 

 it should be regarded as the form known to LlNXAEUS as Oenothera 

 biennis and consequently to be regarded as the tj'pe form of the species. 



Vx\v».vv.Ctt.ta. % VltnnLS 



Vvs,tvT\v.S X"rt\u.Ticata 



Vitn 



nis 



•m.u.rtca'ta. 



Fig. 2. Young rosettes. Those of biennis and muricata are of tlie same age but about 



four weeks younger than the hybrids. Those of the hybrids, although strikingly dissimilar 



to one another and patroclinous, present evidence of the influence of botli parents. 



In former papers I have spoken of it as the Dutch biennis and in my 

 cultures I have called it biennis H to distinguish it from American 

 plants, biennis A and biennis D, which have been employed in my crosses 

 with 0. grandifiora. We now know that my plants, biennis A and 

 biennis D, are species distinct from the Dutch plant {biennis H). The 

 species Oenothera biennis Linnaeus is very old having apparently been 



12* 



