In eastern gamagrass (Tripsacum dactyloides) seeds, removal of the indurate cupule enclosing the caryopsis resulted in relatively rapid and high levels of germination regardless of seed pretreatment and across a wide range of incubation temperatures during germination. Seeds incubated at room temperatures with cupules removed had 58%-86% germination, compared with 10%-26% germination for seeds with cupules. Enriched levels of 5% CO2 either had no effect on germination, compared with the germination response under ambient levels of CO2, or germination was enhanced as a function of treatment conditions and seed source. Annual seed production was estimated to be ca. 412/m2. Seed predation, almost entirely by small rodents, was estimated to be ca. 95% of the annual seed crop. Peak aboveground green biomass standing crop was estimated as 1,258 g/m2; of this, only 67 g/m2 were allocated to reproduction. It took ca. 6 days (144 h) for caryopses to pass through a cow's digestive system; 51 of 500 caryopses passed through the digestive system without apparent mechanical damage, and some retrieved seeds germinated.