Weissia inoperculata, a Californian endemic moss is confirmed from a second locality nearly 60 years since its original discovery. Detailed information is given on its morphology and ecology, and a comparison of similar species is discussed. Previous reports of this moss were based on misidentifications of other species of Weissia. The presumed rarity of this grassland species may be a function of its exceedingly small size coupled with a very narrow growing season when plants with capsules are present. The range of this species is extended northward in the Coast Ranges from the type locality by approximately 156 air km.