Rickenella: two species, R. setipes (= R. swartzii) and R. fibula, occur in northern California; both species are common in mosses which occur on the ground. R. setipes has a deer-brown pileus, the umbilicus of which is dark to blackish and a brownish stipe with a violet apex. R. fibula has an orange-red pileus, an orange stipe, and yellowish gills. Both species have a pileus that is 5-10 mm broad and a stipe which is 2-5 mm long; thus these are tiny species which can barely be seen growing in mosses.