90 The Plant World. 



to be observed is: the longer the period from roset to inflores- 

 cence, the greater the chance of fasciation becoming manifest. 

 De Vries * reached similar conclusions with Dipsacus sylvestris 

 torsus. 



When the experiment is carried further and we take the 

 seed of the non-fasciated individuals and sow it, we obtain a 

 third generation in which, given the same favorable conditions 

 under which we raised the second generation, numerous fasciated 

 individuals will make their apj^earance. Again using a fasciated 

 strain of Delphinium hybrid urn for pur])oses of illustration, it 

 was found that no appreciable difiference could be noted in the 

 percentage of fasciation in plants raised respectively from seed 

 obtained from fasciated spring inflorescences, from spring in- 

 florescences of plants which showed no fasciation, or from non- 

 fasciated autumn inflorescences of plants which had shown fasci- 

 ation during the spring. In other words, the fasciated character 

 was latent in the non-fasciated members of the second generation 

 as well as in the fall inflorescences which showed no e.xternal 



signs of fasciation. t 



It is even possible for the fasciated character to become 

 latent for several generations as shown by de Vries for Tetragonia 

 expansa, Helianthus annuus and Picris hieracioides.X To the au- 

 thor of the MutationTheory we owe the recognition of the true 

 state of affairs. As the result of his extensive and painstaking 

 experiments with fasciated races, he comes to the conclusion that: 

 "the atavists or non-fasciated specimens of the race are to be 

 considered as reversions (Riickschlage) in a morphological sense, 

 i. e., that in their importance for the inheritance of fasciations, 

 they are but little (nur unwesentlich) inferior to the best heirs 

 of the race." ** De \^ries also points out that the percentage of 

 fasciations is governed in the most marked degree by the condi- 

 tions of life. "Das betrefi"ende Verhaltniss ist im hochsten 

 (Trade von der Lebenslage abhangig; diese kann .A.tavisten in 

 Erben und Erben in Atavisten umandern. vSelbstverstandlich 



*de vries, H. Sur la culture des monstrosites. Compt. Reiiil., 128: 125, 1899. 



♦It is, in our opinion, immaterial in the present discussion whether we look upon fasciation 

 as due to the presence, in the nucleus, of a certain 'unit," or to a so-called predispo- 

 sition to fasciation. 



*de Vries, H. Die Mutationstlieurie, 2: 560, 1903. 



*loc. cit. 542. _ 



