Triquetrella C. Müller Hal., 1897.

Our one species of Triquetrella is a plant of sites near the ocean from central Oregon to southern California. It is readily recognized even in the field by the combination of tristichous and papillose lanceolate leaves with broad and obvious decurrencies. The type of Triquetrella californica is reported as having been collected by Henry Bolander on Mount Diablo in Contra Costa County, California, but we have been unable to find the plant in repeated collecting trips to that area. Most occurrences of Triquetrella have been located within ten miles of the ocean. In such ocean-front areas, careful examination of areas immediately downslope to outcropping boulders in coastal grasslands are the most promising locations for finding Triquetrella. Based on its preferred habitat coupled with increasing urban development of coastal California counties, the few remaining occurrences of T. californica suggest that it is among the most threatened of moss species in the state.
see key to Didymodon Etc.

Species included:
Triquetrella californica (Lesquereux) Grout