Seed Germination and Reproductive Strategies in Federally Endangered Harperella (Harperella nodosum Rose, Apiaceae)

ABSTRACT Harperella (Harperella nodosum) is a federally endangered plant with 26 known sites in the southeastern United States. Experiments in the greenhouse and observations in the wild demonstrated that harperella is an annual plant and its seeds can germinate immediately after seed maturation under warm-weather conditions in late summer. Harperella was observed to utilize two complementary reproductive strategies as important adaptations to survival in a frequently flooded, semiaquatic habitat, depending on flooding frequency and amplitude: (a) sexual reproduction during low-water years involving flowering and seed production and (b) asexual reproduction during high-water years involving viability of ramets produced at the nodes.