432 THE STRUCTURE OF EVOLUTIONARY THEORY
practical point, de Vries did not propose that all traditional taxonomy be
restructured. He would allow the Linnaean names to persist as "species," with his
smaller, "real" units termed "elementary species." (De Vries did not follow his own
recommendation consistently, for he gave new species names, in traditional
Linnaean form, to his mutational variants. For example, the large tetraploid
became Oenothera gigas derived from O. Lamarckiana). In this argument, de
Vries supported a movement, then current in systematics, to designate the
traditional Linnaean units as linneons and the true-breeding subtypes as jordanons
(to honor the botanist Alexis Jordan)—recognizing both as species of different
sorts and by different criteria (with the jordanon as "more" biological and the
linneon as tolerated by practical necessity). De Vries wrote:
We may conclude that systematic species, as they are accepted nowadays,
are as a rule compound groups. Sometimes they consist of two or three, or a
few, elementary types, but in other cases they comprise 20, or 50, or even
hundreds of constant and well-differentiated forms (1905, p. 38).
The systematic species are the practical units of the systematists and
florists, and all friends of wild nature should do their utmost to preserve
them as Linnaeus has proposed them. These units, however, do not really
exist entities; they have as little claim to be regarded as such as the genera
and families have. The real units are the elementary species ... Pedigree
culture is the method required and any form which remains constant and
distinct from its allies in the garden is to be considered as an elementary
species (1905, p. 12).De Vries' historical argument for changing emphasis from the linneon (ordinary
species) to the jordanon (de Vriesian elementary species) provides an interesting
insight into his worldview and rhetorical style. Before Linnaeus, he claims, genera
stood as the "natural" units of common discourse: "The old vulgar names of plants,
such as roses and clover, poplars and oaks, nearly all refer to genera" (1905, p. 33).
Linnaeus, also searching for the natural unit, failed to extend his argument far
enough. He began with genera and then moved "down" to species. He knew that he
might proceed to still smaller units, but chose to go no further:
Afterwards Linnaeus changed his opinion on this important point, and
adopted species as the units of the system. He declared them to be the
created forms, and by this decree at once reduced the genera to the rank of
artificial groups. Linnaeus was well aware that this conception was wholly
arbitrary, and that even the species are not real indivisible entities. But he
simply forbade the study of lesser subdivisions. At this time, he was quite
justified in doing so, because the first task of the systematic botanists was
the clearing up of the chaos of forms and the bringing of them in
connection with their real allies (1905, p. 34).