The Fruitful Facets of Galton's Polyhedron 427
observation of the origin of species, and of the experimental control thereof"
(1905, p. 550).
De Vries reported different numbers and names for new Oenothera species in
various publications, but the seven cited in his 1904 Berkeley lectures provide a
good feel for his categories and criteria (see Fig. 5-9). Above all, the mutants
appeared suddenly and bred true (other mutants reverted, hybridized, or segregated
in only a proportion of progeny). De Vries placed his seven new species into three
categories. First, he designated two "true elementary species"—the red-veined O.
rubrinervis and the giant O. gigas (a tetra-ploid by later discovery). De Vries
described these new forms as "robust and stark species, which seem to be equal in
vigor to the parent plant, while diverging from it in striking characters" (1905, p.
533). In a second category of "retrograde varieties," de Vries identified the smooth-
leaved O. laevifolia, the short-styled O. brevistylis, and the dwarf O. nanella, "a
most attractive little plant" (1905, p. 531). These new forms also arose with abrupt
distinctness, and bred as true as the two "elementary species," but these three
mutants differed from the parent O. Lamarckiana by loss or diminution of an
ancestral character, not by addition of novelty—hence their separate, and less
admirable, category. (I am intrigued by our cultural bias that designates increased
bulk as a novelty (O. gigas), while ranking shortness as mere subtraction (O.
nanella).) De Vries then placed two forms into a third (and inconsequential) class
of "weak species" that "have no manifest chance of self-maintenance in the wild
state" (1905, p. 537). The whitish O. albida "grows too slowly and is overgrown,"
while the oblong-leaved O. oblongata "bear small fruits and few seeds."
All three central tenets of the mutation theory work in direct opposition to
Darwinian gradualism and sequential shaping by natural selection in the origin of
species—hence the widespread and proper interpretation of de Vries' theory as a
powerful refutation of Darwinism (Kellogg, 1907, who lists the views of de Vries
as an alternative, not an auxiliary, to Darwinism).
- Above all, the mutation theory embodies the most unabashedly saltational
notion ever seriously regarded as an evolutionary mechanism. New species arise in
a single step by a sudden, discontinuous, fully formed and true breeding leap in
phenotype. De Vries could not have been clearer in his introductory comment to
the Mutation Theory (1909a, p. 3): "Species have arisen from one another by a
discontinuous, as opposed to a continuous process. Each new unit, forming a fresh
step in this process, sharply and completely separates the new form as an
independent species from that from which it sprang. The new species appears all at
once; it originates from the parent species without any visible preparation and
without any obvious series of transitional forms."
De Vries explicitly contrasts his new view with Darwinian gradualism: "A
current belief assumes that species are slowly changed into new types. In con-
tradiction to this conception the theory of mutation assumes that new species and
varieties are produced from existing forms by sudden leaps" (1905, p. vii). Such
sudden inception precludes any role for natural selection in the