In Pursuit of the Gene

76 ¨ PANGENES
transported from the nucleus of the flower cell to the cell machinery outside
the nucleus where the dye was actually produced.
¨ DURING THE SUMMER OF 1886, while wandering near the small village
of Hilversum, De Vries happened upon the flowering shrub Oenothera
lamarckiana, popularly known as evening primrose for the way it bloomed in
the early evening. Ironically, O. lamarckiana, which would mesmerize De
Vries for nearly half a century and ultimately lead him astray, carried the
name of a biologist who was immortalized for advocating a highly seductive
but erroneous theory of evolution.
De Vries was filled with anticipation by the sight of the wildly proliferating
Oenothera, which appeared to have spread from a neighboring park and
halfway across an unused potato field to form a jungle of foliage. It was just
such vigorously growing plants that he sought, following the conventional
wisdom that vigorously growing plants were more likely to contain interesting
variants and throw off sports. Upon closer examination he found
that the plants were even stranger than he had dared to hope, showing an
unusual variability in almost every organ and character. The plants held
such a fascination for him that De Vries returned for repeated observations
nearly every week that summer, and sometimes every day, for several
hours at a stretch. That fall, he transplanted nine specimens of O. lamarckiana
to his experimental garden in Amsterdam, and for the following two summers
he continued his close observation of the flowers in the field. During
his second summer of observation, two radically new types appeared, each
type differing from the O. lamarckiana parent to such a degree that De Vries
was certain that he had been witness to the birth of two entirely new species.
In each case the new types appeared in a small cluster of similar plants,
suggesting that a single new variant had given rise to a small colony of descendants.
Meanwhile, the nine plants he transplanted to his experimental
garden in the autumn of 1886 flowered and produced seeds in 1887 and
1888. Among the 10,000 plants grown up from these seeds, De Vries found
what he believed to be 3 mutant plants, which differed so markedly from
their O. lamarckiana parent that De Vries added them to his list of examples