Clonal Diversity in Two Rare Perennial Plants:Sagittaria isoetiformisandSagittaria teres(Alismataceae)

Most perennial herbs can produce clones (genetically identical ramets), and the frequency of asexual propagation relative to sexual reproduction can affect genetic and genotypic diversity. The power to detect clones also depends on marker diversity. Using horizontal starch‐gel electrophoresis, we surveyed two rare perennials found in isolated wetlands:Sagittaria isoetiformis, restricted to the inner coastal plain of southeastern North America, andSagittaria teres, endemic to glacial ponds in northeastern North America. Fifteen polymorphic loci were resolved on 527 individuals across 11 populations (ca. 48 ramets/population) forS. isoetiformis, and 12 polymorphic loci were resolved on 367 individuals across seven populations (ca. 52 ramets/population) forS. teres. Although genets commonly produce clones in these species, we found no significant influence of genotype duplication on genetic structure. Genotypic structure and our power to detect clones did differ among species. The proportion of distinguishable genotypes per population was higher inS. isoetiformis( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $G/ N=0.92\pm 0.12$ \end{document} ) than inS. teres( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $G/ N=0.54\pm 0.21$ \end{document} ). When standardized by the number of polymorphic markers in each population, genotypic diversity was high in both species ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont