Clitocella popinalis is a small agaric fungus in the family Entolomataceae, distributed across temperate northern European countries including Denmark, Norway, and Sweden, where it inhabits grasslands, woodland edges, and disturbed grassy areas. The species is characterized by its modest, greyish-brown to pale buff cap, decurrent or adnate gills, and slender stipe typical of the broader Entolomataceae assemblage to which it belongs. Like many members of this family, C. popinalis produces pink-spored fruit bodies with angular, isodiametric spores visible under microscopy, distinguishing it from superficially similar species. It is a saprotrophic or potentially mycorrhizal fungus contributing to nutrient cycling in grassy and semi-open habitats. The species is currently assessed as Least Concern within its European range. However, like many fungi of traditional pastures and unimproved grasslands, it may be sensitive to habitat intensification, nitrogen enrichment from agricultural runoff, and the loss of old, unfertilized grassland habitats that support diverse fungal communities throughout Scandinavia.