YELTON, SHARON1* and ROBERT F. NACZI2. 1Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, U. S. A.; 2Northern Kentucky University, Department of Biological Sciences, Highland Heights, KY, 41099, U. S. A.. - Sectional circumscription and relationships of gynecandrous Carex subgenus Vignea (Cyperaceae) based on morphology.
Carex is one of the ten largest genera of flowering plants in
the world, containing about 2500 species. Despite its great size and
ecological importance, there has been little phylogenetic analysis
within the genus. Nearly all of the classifications that do exist are
strictly phenetic and, therefore, probably not natural. One probable
clade within subgenus Vignea contains eight sections (about 165
species) and can be recognized by the presence of gynecandrous spikes.
The clade is wide-ranging in occurrence and especially diverse in
Eastern North America. We used micromorphological and anatomical data
to reconstruct the phylogeny of sections within this clade. Characters
include: macromorphology (especially reproductive features), culm
anatomy using light microscopy, perigynia anatomy using light
microscopy, and achene surface morphology using scanning electron
microscopy. We polarized character states using a composite outgroup
of nongynecandrous species within subgenus Vignea. Using
parsimony methods, we conducted a phylogenetic analysis of these data.
Our preliminary results of the sections we have studied indicate the
following phylogenetic hypothesis: (Stellulatae + (Carex
seorsa + ((Glareosae + Deweyanae) + (Remotae
+ (Cyperoideae + (Ovales + Planatae)))))). Our
preliminary results also provide placement for two previously
problematic species. We found that Carex seorsa, previously
placed in section Stellulatae, belongs in a separate,
apparently undescribed section. Our data also indicate a resolution of
the controversial placement of Carex laeviculmis, placing the
species in section Glaraeosae.
Key words: Carex seorsa, gynecandrous, morphology, subgenus Vignea