Germination of prostrate spurge (Euphorbia supina Raf.) seeds collected in August, September, October, and November 1977 at Riverside, California was 53, 30, 18, and 16%, respectively. Stratification of seeds collected in August, September, and October at 5 C for 3 weeks or more increased germination to 70 to 80%. Prostrate spurge seeds germinated at constant temperatures of 20 to 40 C, with optimum temperatures of 25 to 30 C. Maximum germination occurred under alternating temperatures with a high temperature of 30 to 35 C and a low temperature of 15 to 25 C. Germination in the dark was much lower than in the light. Seedling establishment of seeds collected in August sown at 0.0- to 0.5-cm depths was 30 to 35%, but establishment from 2 cm declined to near 0%. Light intensity did not affect the number of seedlings established, but the seedlings established were larger under higher light intensities.
