Seeds from nine species of desert annuals native to the Mojave and Sonoran Deserts were stored at constant temperatures of 4°, 20°, 50°, and 75°C. All species except one, when stored at 50°C, reached maximum germination within the first 5 weeks of storage. Seeds stored at 75°C failed to germinate while seeds stored at 4°C gave poor germination, equivalent to fresh seeds. Seeds stored at room temperature (20°C) need 5 months' maturation to achieve comparable germination percentages. The prevalent high temperatures in the following seed dispersal probably promote seed maturation in desert plants.