SLOMBA, JONATHAN, M.*, FREDERICK, B. ESSIG, and JAMES, R. GAREY. Department of Biology, University of South Florida, SCA 110, 4202 E. Fowler Ave., Tampa, Fl., 33620-8000. - A re-evaluation of the infrageneric classification of Clematis (Ranunculaceae) using chloroplast DNA sequences.
Clematis is a large cosmopolitan genus of more than 300
species. With a distribution that spans all continents save
Antarctica, members of the genus have been sought after by
horticulturalists the world over. Due to such intense interest the
classification of Clematis has been revised numerous times over
the last 300 years. The most widely accepted, current, classification
based on traditional morphology was put forth by Tamura in 1968,
revised in 1989, and modified further by Johnson in 1997. This
classification is based largely upon floral characteristics such as
size, shape and color as well as minor differences in vegetative and
inflorescence morphology. Essig in 1990 suggested an alternative
classification scheme based upon seedling morphology and reproductive
compatibility. Essig proposed two natural groups which would encompass
the traditional sections. Sequences of the chloroplast encoded
trnL intron and trnL-F intergenic spacer were examined
to test which hypothesis accurately represents the phylogenetic
relationships within the genus. The two chloroplast regions (approx.
720 bp.) will be augmented with matK, also chloroplast encoded,
sequence data as well as a morphological data set. Preliminary
sequence analysis of ten ingroup taxa and one outgroup taxa
(Anemone spp.), utilizing the trnL intron and
trnL-F intergenic spacer regions, shows moderate support for
Essig's "seedling hypothesis". These findings provide
insights into characters that could potentially hold vast amounts of
phylogenetic information within this group.
Key words: Chloroplast, Clematis, Phylogeny, Ranunculaceae, trnL intron, trnL-F intergenic spacer