Recent Papers on CEnothera Mutations. 29!^ 



first colonized, and that any such crosses would therefore have been 

 repeatedly made there long before the interference of man. Another 

 weakness of this view is that there is no particular reason for 

 supposing that 0. Laiiiarckiana characters can be duplicated by 

 single crosses between biennis and grand iflofa, any more than biennis 

 could be produced by crosses between muricata and grandijiora. 



It has been suggested by Davis (10) that O. Lamarckiana 

 Seringe is only a form of O. grandiflora Solander. The suggestion 

 is based ciiiefly on a comparison of photographs of the type 

 specimens in the Musdum d' Histoire Naturelle in Paris. 



The new introduction of O. grandiflora from Alabama in 1778 

 was, no doubt, at least slightly different from the " Virginian 

 grandiflora" of Ray and Barrelier, and it appears probable that 

 Seringe meant to express this difference in recognizing Lamarckiana 

 as well a.s grandiflora. In any case it is obvious that the question 

 cannot be settled merely by determining the source of De Vries's 

 race of Lamarckiana in 1860, for the origin of the much older race 

 oi Lamarckiana in England must also be considered, and this may 

 easily go back to the time of Ray. 



Since it is now clear that numerous races both of grandiflora 

 and Lamarckiana exist, it seems possible that the original seeds of 

 the large-flowered form brought from "Virginia" contained a 

 mixture of interbreeding races, some of which would now be classed 

 with either species. Certain of the CEnotheras now grown in 

 English gardens might very well represent such intermediate races. 

 Considering the great number of local geographic races of O. biennis 

 now being described, it is probably safe to assume that the grandi- 

 flora of Virginia was different from that of Alabama. 



Finally, three of the recent papers have dealt with various 

 general aspects of the mutation problem. These papers are by 

 De Vries (12), Heribert-Nilsson (24) and Gates (21). De Vries 

 reviews the progress which has been made in the study of mutations, 

 particularly in CEnothera, and reafifirms his earlier views, such as the 

 premutation theory. He points out that natural selection, mutation 

 and orthogenesis are not mutually exclusive as evolutionary factors, 

 but that all have probably played their part. Heribert-Nilsson 

 contributes a mass of breeding data on a Swedish race of 0. 

 Lamarckiana, and attempts to explain the mutation phenomena in 

 terms merely of Mendelian splitting. In doing so he disregards the 

 cytological facts and frequently runs counter to them. He elaborates 

 a purely hypothetical theory involving the gradual accumulation of 

 unit-factors or genes in particular germ-cells, but his theory falls to 

 pieces in the light of the cytological facts. As the writer has 

 pointed out, the Mendelian theory of mutation has been disproved 

 and the premutation theory of De Vries rendered unnecessary by 

 the study of the nuclei. The time has come for a new theory of 

 mutation, based on our present cytological and experimental data, 

 and the main achievement of the last three years has been to show 

 that mutation is an independent process requiring a special 

 explanation. 



