58
DAVID D. KECK
flowering and fruiting. In connection with the herbarium he will find
the library an equally indispensable tool for his work.
Ecology can contribute additional data of great value. The local
environment of the plant as well as its geographic and climatic distribution are important considerations. Sister species rarely occupy the
same habitat (sympatric species), although it is a common characteristic
for them to occur near to one another (allopatric species). They may
be allopatric from several causes, one of which is different habitat preferences, i.e., they may be physiologically somewhat different. It is
part of the task of the monographer to be on the lookout for, and to
record, such differences.
Strangely, the importance of geographic distribution in systematic
botany gained recognition slowly. Plants that were thought to resemble
one another closely were placed together irrespective of where they
were native, whereas closer inspection later, with their quite different
origins in mind, often disclosed other differences adequate for distinguishing them.
Field studies provide a potent tool for the systematist. Problems may
be first discovered there or in the herbarium. In either case a natural
reaction is to seek confirmation or a solution at the other source. Plants
in the field are observed in their natural habitat, surrounded by their
customary associates, exhibiting a range of variation consonant with
the environmental factors of the locale and of the genetic potential of the
local population and any adjacent close relatives. Many problems raised
by herbarium observation may be resolved in the field.
Field studies may range all the way from simple examination of a
character or two in a population to an intensive investigation employing
quadrats, statistics, mapping, etc., as a means of evaluating the structure
of a local population and possible incipient spatial diversification within
the species. An excellent example of the latter type of field work is
that on the distribution of flower color in a desert annual, Linanthus
parryae (Gray) Greene, by Epling and Dobzhansky (1942).
The extent of variation in the local taxonomic unit can be studied by
field examination over its entire geographic range. Where its range infringes upon that of a relative, evidence of hybridization can be looked
for and quite often found.
Up to this point consideration has been given to the conventional
tools usually employed by all taxonomists. Now some of the less usual
sources of data for the solution of taxonomic problems will be briefly
discussed.
DAVID D. KECK
flowering and fruiting. In connection with the herbarium he will find
the library an equally indispensable tool for his work.
Ecology can contribute additional data of great value. The local
environment of the plant as well as its geographic and climatic distribution are important considerations. Sister species rarely occupy the
same habitat (sympatric species), although it is a common characteristic
for them to occur near to one another (allopatric species). They may
be allopatric from several causes, one of which is different habitat preferences, i.e., they may be physiologically somewhat different. It is
part of the task of the monographer to be on the lookout for, and to
record, such differences.
Strangely, the importance of geographic distribution in systematic
botany gained recognition slowly. Plants that were thought to resemble
one another closely were placed together irrespective of where they
were native, whereas closer inspection later, with their quite different
origins in mind, often disclosed other differences adequate for distinguishing them.
Field studies provide a potent tool for the systematist. Problems may
be first discovered there or in the herbarium. In either case a natural
reaction is to seek confirmation or a solution at the other source. Plants
in the field are observed in their natural habitat, surrounded by their
customary associates, exhibiting a range of variation consonant with
the environmental factors of the locale and of the genetic potential of the
local population and any adjacent close relatives. Many problems raised
by herbarium observation may be resolved in the field.
Field studies may range all the way from simple examination of a
character or two in a population to an intensive investigation employing
quadrats, statistics, mapping, etc., as a means of evaluating the structure
of a local population and possible incipient spatial diversification within
the species. An excellent example of the latter type of field work is
that on the distribution of flower color in a desert annual, Linanthus
parryae (Gray) Greene, by Epling and Dobzhansky (1942).
The extent of variation in the local taxonomic unit can be studied by
field examination over its entire geographic range. Where its range infringes upon that of a relative, evidence of hybridization can be looked
for and quite often found.
Up to this point consideration has been given to the conventional
tools usually employed by all taxonomists. Now some of the less usual
sources of data for the solution of taxonomic problems will be briefly
discussed.