Systematics Section / ASPT
Groff, Paul A. , Eliason, Scott , Whitlock, Barbara A. .
Two lineages of Gentianopsis in the San Bernardino Mountains, cryptic geographic variation, and the circumscription of G. holopetala (“Sierra gentian,” Gentianaceae).
CALIFORNIA’S San Bernardino Mountains (SBM) harbor a number of disjunct plant populations whose closest relatives occur in the Sierra Nevada or in more distant mountains. Parish, Jepson, Mason, Munz, and others include in the SBM flora two such taxa, currently recognized as Gentianopsis holopetala (“Sierra gentian”) and G. simplex. The presence of G. simplex in the SBM is undisputed. However, Gillett’s Gentianella monograph and the 1993 Jepson Manual omit the SBM from the range of G. holopetala. We report the 2004 rediscovery of a small, vulnerable population of Gentianopsis from Bow Meadow, Bear Valley. This is likely the population that led G. holopetala to be included in the SBM flora. Two 1895 specimens in the California Academy of Sciences herbarium, evidently unexamined in recent years, appear to be the only other vouchers for this population. Ongoing morphological studies and phylogenetic analyses of nuclear and chloroplast DNA sequences throughout the genus confirm that the 2004 Bow Meadow collections are not G. simplex. They belong to a well-supported monophyletic group within Gentianopsis (the “detonsa/crinita clade” ) and, more narrowly, form a well-supported subclade along with populations from the Western Great Basin previously identified as G. holopetala. However, molecular data do not support monophyly of G. holopetala as traditionally circumscribed, suggesting a pattern of cladogenesis and genetic divergence without substantial morphological change in some lineages. If further data continue to support this phylogeny, taxonomic reduction or splitting of G. holopetala may be appropriate. We discuss implications for conservation of Bow Meadow. In previous studies of the origin and evolution of the SBM flora, genetic evidence for historical-biogeographic hypotheses has been sparse. We develop a context for phylogeographic studies within Gentianopsis, and propose comparative studies of other montane-to-subalpine wet-meadow species with disjunct populations in the SBM.
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1 - P.O. Box 144156, Coral Gables, Florida, 33114, USA
2 - U. S. Forest Service, San Bernardino National Forest, P. O. Box 290, Fawnskin, California, 92333, USA
3 - University of Miami, Department of Biology, 1301 Memorial Drive, Coral Gables, Florida, 33124, USA
San Bernardino Mountains
Parish, Samuel B.
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 10:15 AM