Clonality and genetic diversity in the eastern North American spring ephemeral Erythronium americanum Ker-Gawl. (American Trout Lily)

As an adaptation to unpredictable light and pollination levels in the deciduous forest, clonality in early spring flowering plants enables continued population persistence but can have profound impacts on the population genetic structure. To gain a better understanding of clonal diversity in the common spring ephemeral herb Erythronium americanum (American Trout Lily) and its relationship to population size, five populations were examined using microsatellite markers. In general, levels of genetic diversity were low, with larger and more dense populations of E. americanum exhibiting less allelic diversity than smaller and less dense populations. Over half (68.56%) of sampled individuals overall were clones, with populations containing 2-21 clones and larger populations possessing the fewest number of clones. Several factors may contribute to these patterns, including geitonogamy, genetic drift, and intraspecific competition. The patterns of allelic diversity across the range indicate two distinct genetic clusters of E. americanum with northern and southern groups separated at the Ohio River valley.