TRENDS IN SYSTEMATIC BOTANY
63
Chaney in the United States, and many others cannot be reviewed here.
Ordinarily the paleobotanical data are most useful in tracing the development of the higher taxonomic categories, from the genus upward.
In special instances, however, the fossil evidence is applicable in helping
to establish the relationships of living plants even on the species level,
as shown by Mason (1949) for the section Insignes of the genus Finns
on the Pacific Coast of North America.
X. PARASITISM
Gibbs (1954) has pointed out that parasitism is a useful tool in
phylogenetic studies. In discussing hemiparasites which attach themselves to the roots of their hosts and make some food for themselves, he
writes: "Those parasites which have thus become highly specialized are,
we may be sure, adapted to the chemistry and physiology of their hosts.
It is therefore likely that groups of closely related parasites will attack
groups of closely related hosts. It is but a step to imagine that we may
get clues to the relationships of host organisms, plant and animal, from
a study of their parasites, and vice versa." He follows this up with a
discussion of the smuts that have exacting morphological requirements
on certain species of Carex, and of the rust that supports other evidence
for a close relationship between the Empetraceae and the Ericaceae.
XL BIOCHEMISTRY
Early attempts to apply biochemical data to taxonomic questions were
highlighted by the investigations of Carl Mez (1926) and his colleagues
at Koenigsberg, Germany. They used serological bioassay methods to
help decide angiosperm family relationships. To outside observers it
seemed that the results of these studies were astonishingly parallel to
the Englerian phylogenetic scheme, which through other methods of
investigation appeared to have numerous discrepancies that would
scarcely warrant one to anticipate such close corroboration. The work
of the Mez school was accordingly not widely accepted. Recently the
serological method has been taken up again from a fresh viewpoint
(Johnson, 1953), but it is still too early to evaluate the results.
Plant chemistry can supply other data of use to the taxonomist. This
is based on the supposition that related plants will have a similar chemistry, although the reverse proposition is not necessarily true. Suitable
comparative chemical tests, when carried out systematically, should be
helpful as supplementary data in establishing plant relationships. For
example, lignin analyses seem to be of considerable potential taxonomic
63
Chaney in the United States, and many others cannot be reviewed here.
Ordinarily the paleobotanical data are most useful in tracing the development of the higher taxonomic categories, from the genus upward.
In special instances, however, the fossil evidence is applicable in helping
to establish the relationships of living plants even on the species level,
as shown by Mason (1949) for the section Insignes of the genus Finns
on the Pacific Coast of North America.
X. PARASITISM
Gibbs (1954) has pointed out that parasitism is a useful tool in
phylogenetic studies. In discussing hemiparasites which attach themselves to the roots of their hosts and make some food for themselves, he
writes: "Those parasites which have thus become highly specialized are,
we may be sure, adapted to the chemistry and physiology of their hosts.
It is therefore likely that groups of closely related parasites will attack
groups of closely related hosts. It is but a step to imagine that we may
get clues to the relationships of host organisms, plant and animal, from
a study of their parasites, and vice versa." He follows this up with a
discussion of the smuts that have exacting morphological requirements
on certain species of Carex, and of the rust that supports other evidence
for a close relationship between the Empetraceae and the Ericaceae.
XL BIOCHEMISTRY
Early attempts to apply biochemical data to taxonomic questions were
highlighted by the investigations of Carl Mez (1926) and his colleagues
at Koenigsberg, Germany. They used serological bioassay methods to
help decide angiosperm family relationships. To outside observers it
seemed that the results of these studies were astonishingly parallel to
the Englerian phylogenetic scheme, which through other methods of
investigation appeared to have numerous discrepancies that would
scarcely warrant one to anticipate such close corroboration. The work
of the Mez school was accordingly not widely accepted. Recently the
serological method has been taken up again from a fresh viewpoint
(Johnson, 1953), but it is still too early to evaluate the results.
Plant chemistry can supply other data of use to the taxonomist. This
is based on the supposition that related plants will have a similar chemistry, although the reverse proposition is not necessarily true. Suitable
comparative chemical tests, when carried out systematically, should be
helpful as supplementary data in establishing plant relationships. For
example, lignin analyses seem to be of considerable potential taxonomic