554 THE EVENING PRIMROSES OF DIXIE LANDING, ALABAMA. 



Lamarckiana x Oe. biennis "Chicago", has already been described, 

 the other pair, from the reciprocal cross, will soon be published in 

 another paper. Possibly one group of the Dixie Landing types is 

 related to Oe. grandiflora in the same way that Oe. densa and Oe. 

 laeta are related to Oe. Lamarckiana, and the other group to Oe. 

 Tracy i as Oe. laxa and Oe. velutina are related to Oe. biennis "Chi- 

 cago." Of course the situation at Dixie Landing is probably com- 

 plicated by the recrossing of the hybrids with themselves and with 

 their parents. However that may prove to be, the Dixie Landing 

 types are now available for study and it is hoped that future work 

 may show in what manner they are related. At the present time no 

 conclusion regarding them is justified other than that they con- 

 stitute so mixed a population that it is quite impossible to distinguish 

 original parent types, if any such exist there, from the derivative 

 types associated with them. In case the two most common types 

 represent the original strains, the presence in other types of cha- 

 racters which are not common to either hypothetical parent sug- 

 gests that Oe. grandiflora and Oe. Tracyi may prove to be additions 

 to the list of species, including Oe. Lamarckiana, Oe. cruciata "Adiron- 

 dack," European Oe. biennis and Oe. biennis "Chicago," which are 

 known to be in a mutable condition. 



Hortus Botanicus, Hugo de Vries, 



Amsterdam. 

 Bureau of Plant Industry, H. H. Bartlett, 



Washington, 



(Science, N. S., Vol. XXXV, No. 921, Pages 599-601, 

 November i, 1912.) 



