A number of poisonous and inedible white mushrooms can appear similar, including those that have acquired a funnel-ish shape from becoming upturned and exposing their gills in age. For example, the inedible
Leucopaxillus albissimus can appear similar when old. Although its gills extend into the stem, they differ in being "true" (i.e., blade-like) gills rather than ridge-like, false gills.
See also the closely related and edible
Cantharellus formosus,
Cantharellus californicus, and
Cantharellus roseocanus.