[Wikipedia] Habitat, Seed Longevity: Plants need bare soil or soil without any exotic weed competition to thrive, and can even grow in the bare soil of well worn trails. Late-flowering from August to October, and one of the last of the summer California wildflowers to bloom. Plants are able to grow without any rainfall or any moisture in the ground around their roots, surviving by absorbing dewfall at night through their leaves. Ripe seeds germinate readily, 40% in three days and 80% within 15 days. When managing or restoring this species, the estimated longevity of seeds in the soil is between 100 and 250 years. (link added by Mary Ann Machi)