Mutation in the CEnotheras. 



U 



case with CE. nanella. OE. cruciata was so distinct that he was 

 disposed to consider it a good species. In the second year all 

 the forms cultivated in the Abbe's own garden reverted to (E. 

 rubrinervis, while those at the Jardin des Plantes, grown from the 

 seeds of the Gi. Lamar ckiana and CE. rubrinervis of the preceding 

 year, were more or less nearly identical. Two forms of CE. 

 rubrinervis, which had appeared the first year, continued con- 

 stant, but difi"ered merely in foHage. Plants from last year's 

 CE. gigas showed reversion either to CE. Lamarckiana or (E. 

 rubrinervis. Only CE. cruciata remained distinct. 



The third year all the young plants, from the different forms, 

 reverted to CE. rubrinervis. The most interesting development 

 of the present year concerned the original plants, which proved 

 distinctly perennial and flowered freely, but exhibited decreas- 

 ingly well marked differences, and a greater or less tendency 

 toward CE. rubrinervis. CE. cruciata still retained its markedly 

 distinctive character. 



The next year, CE. cruciata, hitherto so constant, and now 

 four years old, produced from the same stem the large flowers of 

 CE. parviflora and its own small cruciate blossoms. A good 

 figure shows these very different flowers borne each on an op- 

 posite branch of the same stem. For the rest there remained 

 the robust Q£. rubrinervis, reverting to the original stock (stirp) , 

 and bearing the flowers of CE. biennis. 



Among the conclusions drawn by the author from his ex- 

 periments are some not without interest to the student of muta- 

 tion. He defines mutation as consisting in an inherent tend- 

 ency in the seeds of plants which causes them suddenly to pro- 

 duce a number of individuals more or less different from the 

 parent. That these aberrant characters should persist and de- 

 velop it is necessary that their environment should be notably 

 unlike that in which the seed was produced, otherwise a reversion 

 to the parent stock will occur in the third or fourth year. 



The leaves, the degree of hairiness, the size of the flowers, 

 all vary so greatly in CEnothera as to be without value in the de- 

 limitation of species. Since vegetative organs vary in accordance 

 with the environment, it would seem that the specific entity 

 which manifests itself in the whole character of the plant should 

 be sought in an anatomical or morphological study of the seed. 



