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 Speczes 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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