BOTANY 



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(QEnothera) and other forms. From carefully 

 controlled pedigree cultures de Vries showed, 

 particularly in the (Enotheras, that new forms, 

 differing in many characters from the parent 

 species, suddenly arise as variations or mutations 

 and perpetuate their peculiarities in later genera- 

 tions. The majority of these forms differed from 

 the parent species of de Vries' experiments 

 (CE. Lamarckiana) not in single characters, but 

 in all their parts. A mutation such as nanella was 

 not only a dwarf, but also differed conspicuously 

 in the size of its flowers and the shape of its leaves. 

 It was recognisable as a new type from the first 

 leaves following the cotyledons, and the same is 

 true of many of the others. Another mutant, 

 lata^ not only differs strikingly in its leaf characters, 

 but also in habit, in the shape of its buds and 

 petals, and in the sterility of its pollen. This 

 type will be referred to again later. Perhaps a 

 dozen mutations in all were described by de Vries 

 as arising suddenly and perpetuating their charac- 

 ters in later generations. Many others have been 

 described since. 



The publication of these results was concluded 

 in 1903, and if I may be permitted to refer to my 

 own interest in them, it was primarily to deter- 

 mine the nature of the change when a new type 

 appeared. What had happened in the interior 

 of the plant, in its germ-cells, to give rise to the 



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