Pleurozium Mitten, 1869.

In most northern regions including Oregon, Pleurozium is one of the most common mosses in a variety of habitats ranging from coastal bogs to montane forests to alpine timberline krummholz. Puzzlingly, it has not yet been found in California. It is a large plumose moss with reddish stems and with bluntly rounded leaves. The only moss that can be confused with Pleurozium is Entodon concinnus. This latter moss is not yet found in the area covered by this key, but its occurrence is a definite possibility. Pleurozium schreberi will surely be found in boggy sites in northern California, but this finding has the potential of instead being Entodon concinnus. These two mosses can occupy similar habitats and so closely resemble one another as to require a cross-section through the alar region. Pleurozium schreberi has a unistratose alar region; E. concinnus has a bistratose alar region.
see key to Hylocomium Etc.

Species included:
Pleurozium schreberi (Bridel) Mitten, not known from CA