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Fourwing saltbush (Atriplex canescens) is a widely distributed shrub of semiarid western North America. We studied viability and germinability of fourwing saltbush seeds over 10 years for collections from 23 Intermountain populations. Fruit fill averaged 53 percent, and 96 percent of filled fruits contained viable seeds even after 6 years of laboratory storage. Seed collections were generally dormant to some degree at harvest and lost dormancy via two processes, moist chilling and after-ripening in dry storage. Prolonged chilling (24 wks) substituted for dry after-ripening, resulted in germination percentages similar to those obtained without chilling after 2 years of storage. Collections from warm desert habitats were generally least dormant, while collections from pinyon-juniper and mountain brush habitats were highly dormant. But these trends were not very strong. Seeds of the diploid population from Jericho Dunes were essentially nondormant at harvest, while those from a population near Page, Arizona, were essentially completely dormant. Unchilled seeds did not germinate to any degree until tested after 10 years of storage. Patterns of dormancy loss suggest that this species is opportunistic and generally able to establish in response to either winter or summer precipitation. In addition, its seeds probably form persistent seed banks in the field.