Crumia W. B. Schofield, 1966.

The world's only species of Crumia is endemic to west coastal North America where it grows in creeks or on seepages, primarily in somewhat calcareous or alkaline regions where it is usually encrusted with precipitate. As a spatulate-leaved pluripapillose acrocarpous moss, it may be reminiscent of Syntrichia or Tortula. Until sporophytes with peristomes were found, Crumia was placed in the affinity of the gymnostomous genus Scopelophila. The suggestion of relationship to Scopelophila was based upon possession in common of a limbidium of enlarged and thick-walled isodiametric cells. A similar pattern of marginal differentiation is also found in the genus Scouleria (perhaps more related to Grimmia). The darker colored border of the spatulate leaves is highly diagnostic in the field.
see key to Scouleria Etc.

Species included:
Crumia latifolia (Kindberg ex Macoun) W. B. Schofield