STEVENS, PETER F. Department of Biology, University of Missouri St Louis, MO 63121-4299, and Missouri Botanical Garden, PO Box 299, St Louis, MO 63166-0299. - Organisms, form and characters.
In the development of phylogenetic systematics over the last decade
our approach to morphological characters has remained at a
preDarwinian level, even as we use ever more sophisticated tools for
looking at plants. A largely neglected area surrounds the
relationships between observers, characters, their states, and
organisms. One especially problematic set of issues concerns the
documentation of morphological observations and their general
availability, whether as measurements, s.e.m.s, etc. (cf. gene
sequences in GenBank, and associated voucher specimens). Another
concerns the relationships between observations and characters and
states. Are there alternative ways in which an organism can be
atomised into characters that would aid our understanding (perhaps
think of the monocot flower here)? Are there alternative ways a
character can be atomised into states? How can we justify one
atomisation over another in any particular situation? Do we have to?
Does terminology constrain our vision of the world, and, if so, how?
What is the relationship between the purely morphological and the
systematic approaches to studying plants? We will discuss these and
related questions as they arise during the session.
Key words: character states, characters, morphology, observation, systematic theory, terminology