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1 October 2006 Taxonomy and Evolutionary Relationships in the Saxifraga rivularis Complex
Marte Holten Jørgensen, Reidar Elven, Andreas Tribsch
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Abstract

In many arctic-alpine plant groups, reticulate evolutionary histories have resulted in problems with species delimitation and phylogenetic reconstruction. In the Saxifraga rivularis complex (2n  =  26, 52), the number of species accepted ranges from a single polymorphic one (S. rivularis s.l.) to several (the circumpolar S. hyperborea, the amphi-Atlantic S. rivularis, the three amphi-Pacific species S. bracteata, S. flexuosa, and S. arctolitoralis, and S. debilis in the Rocky Mountains). A combination of molecular (AFLPs), flow cytometrical, and morphological data from samples covering most of the distribution range was used to delimit taxonomic species and to unravel their evolutionary relationships. Four lineages with distinct morphological differences were recognized, representing four species: the diploids S. bracteata, S. hyperborea (including S. flexuosa), and S. debilis, and the tetraploid S. rivularis (including S. arctolitoralis). Based on a synthesis of the available data we provide a taxonomic revision of the complex and propose one rank change (S. rivularis subsp. arctolitoralis comb. et stat. nov.). Genome sizes as well as the intermediate position of the S. rivularis lineage in the molecular and morphological analyses suggest a single allopolyploid origin from the S. bracteata and the S. hyperborea lineages, most likely in Beringia.

Marte Holten Jørgensen, Reidar Elven, and Andreas Tribsch "Taxonomy and Evolutionary Relationships in the Saxifraga rivularis Complex," Systematic Botany 31(4), 702-729, (1 October 2006). https://doi.org/10.1600/036364406779695988
Published: 1 October 2006
JOURNAL ARTICLE
28 PAGES


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KEYWORDS
AFLPs
allopolyploidy
biogeography
cytology
morphology
reticulate evolution
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