Genetic Variation, Clonal Structure, and Mating System of the Imperiled Eastern Mountain Avens (Geum peckii) and Its Separation from Spreading Avens (G. radiatum)

The Globally Imperiled (G2), yellow-flowered perennial Geum peckii occurs on Brier Island and the White Mountains of New Hampshire, and its close relative G. radiatum occurs in southern Appalachians along the Tennessee-North Carolina border. We genotyped plants from the three geographically distant locations with the aim of addressing questions of taxonomic status, population structure, propensity to reproduce clonally, and propensity to self-fertilize, using 15 microsatellite loci. We find evidence to support the taxonomic status of G. peckii and G. radiatum as separate species. The G. peckii of New Hampshire and Nova Scotia are genetically similar but exhibit genetic differentiation from each other. The G. peckii of New Hampshire show distinct genetic structure at a small scale (10 km), while the G. peckii of Nova Scotia are much more uniform genetically. Clonal reproduction is evident, but our results suggest that ramets found at distances greater than 1 m are unlikely to be members of the same clone. We observe a mixed mating system, with partial outcrossing and partial self-fertilization, based on both field and progeny array studies, and lifetime inbreeding depression of 88%. G. peckii in Nova Scotia appears to possess ample genetic variation combined with very high inbreeding depression, highlighting the importance of establishing and maintaining a suitable environment for its management and recovery.