Ptilidium californicum may be located growing epiphytically on living trees (particularly alder trees), rotting logs, boulders, and cliffs.
Ptilidium californicum has colors that range from rusty brown to dark green.
The soft shoots of Ptilidium californicum are firmly fixed to the substratum.
Shoots are irregularly branched.
Individual lateral leaves have several lobes.
The margins of lateral leaves have cilate teeth. The ciliate teeth are the long finger-like projections extending off of each lobe.
The seta elongates after the sporangium has matured. Spores are released via four lines of dehiscence of the sporangium.