Submitted to: Evolutionary Biology Meeting at Marsielle
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2002
Publication Date: N/A
Technical Abstract: Nymphaea is the most diverse of the eight genera of Nymphaeales and inhabits both tropical and temperate regions worldwide. Several major lineages showing characteristic distribution patterns have been inferred, among which the temperate clade (corresponding to subgenus Nymphaea) is one of the best supported monophyletic groups containing seven species. The present study focuses on reconstructing a phylogeny in temperate Nymphaea based on a broad population sampling, utilizing sequence data from rapidly evolving nuclear and plastid genomic regions, plus morphological characters. Extensive sampling has elucidated patterns of diversification among and within species. North American N. odorata (with subsp. odorata and tuberosa) and N. mexicana (southern United States and Mexico) are basal in the temperate clade. Nymphaea mexicana, which is a temperate to subtropical species, retains the highest number of plesiomorphic morphological character states among other members of the clade. The Eurasian N. alba and N. candida form a group sister to a well-supported lineage containing three dwarf species, N. pygmaea, N. leibergii, and N. tetragona, of which the latter two inhabit boreal regions. Among the dwarf species, molecular data provide clear evidence of the endemic status of N. leibergii in northern North America. The earliest known fossils that can unambiguously be assigned to the subgen. Nymphaea clade date back to 15-20 MYBP. Molecular divergence and substitution rates are analyzed to provide insight into the diversification of taxa in space and time.