Systematics/Phytogeography / Taxonomie/ Section
Jolles, Diana D. , Cruzan, Mitchell, B .
Maintenance of phenotypic polymorphism in Pyrola picta (Pyroleae: Monotropoideae: Ericaceae).
The Pyrola picta species complex (Pyroleae: Monotropoideae: Ericaceae) is comprised of at least three distinct, mycoheterotrophic species inhabiting mature, coniferous forests of western North America. The more ubiquitous progenitor species, P. picta, exhibits extreme phenotypic polymorphism that has historically confounded taxonomic treatments of the species complex based solely on leaf morphology. Although it has recently been shown that gross differences in leaf morphology between individuals belonging to the P. picta complex can generally be attributed to unique species, P. picta often exhibits continuous variation in leaf morphology, preventing definitive identification of species by sight. It is unclear whether phenotypic polymorphism within P. picta is explained exclusively by (1) genetic differentiation, corresponding to previously established phylogeographic patterns, or (2) ecological niches arising in geologic and spatial independence. We characterized floral and vegetative characteristics morphometrically to test the hypothesis that phenotypic polymorphism in P. picta is better explained by adaptation to particular sets of ecological factors, inferred from niche estimation, rather than genetic divergence. Herbarium specimens collected from across the range of P. picta in North America were examined for differences in several leaf and floral characters, and subjected to multivariate statistical analyses to designate phenotypic clusters. Ecological niche estimations based on forest type, annual climatic differences, and geologic history were performed and genetic lineages were estimated from cluster analysis of AFLP. Estimated niches and genetic lineages were compared to determine which better explains phenotypic polymorphism exhibited by P. picta. Although a large proportion of phenotypic divergence is explained by phylogeographic patterns, ecological factors explain some aspects of phenotype, especially for P. picta growing sympatrically with other species in the complex. These results provide new hypotheses about factors that may be responsible for phenotypic polymorphism in P. picta, and patterns of range shift for members of the P. picta species complex.
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1 - Portland State University, Department of Biology, P.O. Box 751, Portland, OR, 97207, USA
amplified fragment length polymorphism
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM