Panarctic Flora

342009-12 The Calamagrostis canadensis-purpurea aggregate C. canadensis, C. phragmitoides, C. purpurea, C. tenuis

Geography: Circumboreal-polar.

Notes: Also in the Calamagrostis purpurea-canadensis aggregate are found morphologically more or less separable tetraploids (presumed sexual) and high-polyploids (presumed agamospermous). At least three morphologically separable sexual tetraploids are known: C. canescens is mainly European and non-arctic, C. purpurea is mainly Siberian, and C. tenuis-angustifolia is found in the amphi-Pacific areas (generally assigned to C. canadensis in North American accounts). Three more or less morphologically separable agamospermous high-polyploids are represented by the names C. phragmitoides in Europe and western Siberia, C. canadensis subsp. langsdorffii (or C. langsdorffii) in northeastern Europe, northern Asia, North America, and Greenland, and C. canadensis s. str. in North America. We accept the sexual tetraploids as three species and the agamospermous high-polyploids as two species - C. phragmitoides and C. canadensis - as there are indications that these two are allopolyploids based on different tetraploidal genomes.