COOK, RACHEL E.* and JOHN C. SEMPLE. University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada. - A biosystematic study of Solidago subsect. Glomeruliflorae Torr. & Gray (Asteraceae:Astereae) in eastern North America.
Solidago subsection Glomeruliflorae Torr. & Gray,
includes all of the goldenrods with flowers in axillary clusters.
Floras include between five and nine species within the subsection,
with the major problem being the members of the
caesia/curtisii/flaccidifolia complex. The goal of this study
was to determine the number of taxa and their ranks. Subsection
Glomeruliflorae is centered in the Appalachian Mountains of
Georgia, Kentucky, Tennessee, North Carolina, South Carolina, and
Virginia with the ranges of some of the taxa extending north into
Ontario, Quebec and the Maritimes, south to Florida and west to
Oklahoma. Field work was undertaken in 1999-2001 to collect specimens
to determine the cytotype distributions within the taxa and for
multivariate statistical analyses including clustering, canonical
variate and discriminate analyses. The results of these analyses
support the recognition of the following species: S. caesia, S.
flexicaulis, S. glomerata, S. macrophylla, S. lancifolia, S.
albopilosa, S. ouachitensis and S. curtisii with S.
flaccidifolia being included within S. curtisii.
Solidago caesia and S. macrophylla were found to be
diploid throughout their ranges. Solidago flexicaulis was found
to be diploid in the northeastern portion of its range and tetraploid
throughout the remainder of its range with the exception of a pocket
of diploid plants in Kentucky. Solidago glomerata is a high
polyploid species with an unstable chromosome number between 2n=96 and
2n=ca.126. Solidago curtisii includes diploid, tetrapoid and
hexaploid plants. Published chromosome counts indicate that S.
ouachitensis is diploid and S. albopilosa is tetraploid.
Both of these species are endangered. There are no reported chromosome
counts for S. lancifolia.
Key words: Asteraceae, biosystematics, cytogeography, Solidago, taxonomy