Spiny Hopsage Germination

Abstract

Germination of spiny hopsage seeds was studied in relation to constant and alternating temperatures and moisture stress. Seeds germinated and developed rapidly with 70% germination at optimum temperatures in 1 week. Optimum germination after 2 weeks of incubation occurred with 5 degrees C nights and 10 to 30 degrees C days. The rapid germination permitted growth on soils that were dried from field capacity to low matric potentials. One seed source from Mojave, California, had unusually high germination at low osmotic potentials in solutions of polyethylene glycol. Nominal seedling establishment occurred when bracted seeds were broadcast on loose seedbeds. Seedlings were not established when threshed or bracted seeds were broadcast on compacted soils.