iiecent Papers on CEnothera Mutations. 296 



IcBvifolia, while one resembled gigas somewhat in foliage, and one 

 was biennis lata, having lata foliage and no pollen, but with small 

 biennis flowers. 



Gates (21) has also obtained a dwarf mutant as well as other 

 variations from wild O. grandiflora from Alabama. He has also (20) 

 cultivated a race of O. gigas identical with that of De Vries, which 

 originated (evidently as a mutation) in the Botanical Garden of 

 Palermo, Italy. This also has twenty-eight chromosomes in typical 

 individuals. Another extensive series of parallel mutations, some 

 of which agree with the De Vriesian forms while others differ widely, 

 has been studied by Heribert-Nilsson (24) in a Swedish race of O. 

 Laiiiarckiana which differs somewhat from the race of De Vries. 

 The giant race in particular is markedly different from the 

 Amsterdam form, though it gives in its progeny one type closely 

 resembling the latter. Of the nine mutant types obtained, only one 

 (lata) agreed entirely with the mutants of De Vries. 



It is evident, therefore, that the mutation behaviour is by no 

 means confined to O. Laiiiarckiana, but is found in other species as 

 well, races even of O. grandiflora showing a certain amount of it 

 when taken immediately from their native wild conditions. Davis 

 (7) has shown that wild O. grandiflora contains a number of bio- 

 types. This is, of course, not surprising, for it is clear that many 

 wild species consist of numerous freely intercrossing biotypes. And 

 it has come to be recognized that numerous open-pollinated species 

 are hybrid in the sense that various biotypes have contributed to 

 their ancestry. 



The activity in the cytological and experimental study of the 

 CEnotheras has led naturally to a much more critical systematic 

 study of the group, with the result that scores of distinct forms are 

 now being recognized which were formerly classed with such species 

 as 0. biennis L. or 0. iiiuricata L. Many of these at least are not 

 merely elementary species in the narrow sense, but forms which 

 stand apart from the described species to a surprising degree. 



Among such new species recently described are O. ornata and 

 0. MacBridece of Nelson from Wyoming. These both have larger 

 flowers and longer styles than O. biennis, thus forming a transition 

 to the large-flowered species. Bartlett has described O. Tracyi 

 from Alabama. This is virtually a small-flowered O. grandiflora. 

 Steele has described a new segregate from the 0. biennis series 

 from Illinois under the name 0. canovivens. Quite recently a very 

 distinct small-flowered form was described by Gates (19) from Ithaca, 

 New York under the name 0. anguslissiiiia, and Bartlett and 

 Atkinson (3) have characterized two other new forms from the 0. 

 biennis series of the same locality, under the names 0. nutans and 

 0. pycnocarpa. In another paper (2) Bartlett concludes that the 

 species now commonly naturalized on the dunes of Holland should 

 represent the type of O. biennis, and he identifies a paler-flowered 

 race which is now common in Holland and which was formerly 

 known under several pre-Linnsean polynomials, as 0, biennis var, 

 sulpkurea De Vries. 



The third part of Ldveill^'s monograph (26) has appeared, but 

 its treatment is not critical and it can be of little benefit in the 

 present intensive study of the genus. 



