The Making of Species 



The classical example of a mutating plant is 

 the evening primrose of the species Oenothera 

 lamarckiana. This is described by De Vries as 

 a stately plant, with a stout stem, attaining often 

 a height of 1.6 metres or more. The flowers 

 are large and of a bright yellow colour, attracting 

 immediate attention, even from a distance. 

 "This striking species," he writes, in Species and 

 Varieties (p. 525), "was found in a locality near 

 Hilversum, in the vicinity of Amsterdam, where 

 it grew in some thousands of individuals. Or- 

 dinarily biennial, it produces rosettes in the first, 

 and stems in the second year. Both the stems 

 and the rosettes were seen to be highly variable, 

 and soon distinct varieties could be distinguished 

 among them. 



The first discovery of this locality was made 

 in 1886. Afterwards I visited it many times, 

 often weekly or even daily, and always at least 

 once a year up to the present time. This stately 

 plant showed the long-sought peculiarity of pro- 

 ducing a number of new species every year. 

 Some of them were observed directly in the 

 field, either as stems or rosettes. The latter 

 could be transplanted into my garden for further 

 observation, and the stems yielded seeds to be 

 sown under like control. Others were too weak 

 to live a sufficiently long time in the field. They 

 were discovered by sowing seed from indifferent 

 plants of the wild locality in the garden. A third 



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