Unispored sporocarps of a Kansas isolate of G. mosseae at all stages of development were prepared for light and scanning electron microscopy to reveal the process involved in peridium formation and spore release. Five stages were identified: 1) peridial hyphal branch origination from below the sporophore attachment; 2) continued peridial hyphal branching and weft formation; 3) adherence of peridial hyphae to the spore wall and completion of peridial expansion into mature state; 4) separation of the primary (evanescent) spore wall layer from the spore and the inner peridial layer; and 5) release of the de‐peridiate spore. Spores in stage 3 were surrounded by a two‐layered peridium consisting of thinner‐walled, parallel‐arranged hyphae next to the spore and thicker‐walled, jigsaw puzzle‐arranged hyphae to the outside; the latter of which collapsed during stages 4 and 5. Fine radial canals and lignituberlike ingrowths were seen in both the de‐peridiate spore wall and, for the first time, in the shed peridium. Comparison of these results with studies of related sporocarpic genera lead to the conclusion that the process of peridium formation in G. mosseae is similar to that of G. coronatum, but that other sporocarpic Glomus representatives must be characterized before valid comparisons may be drawn.