The following information regarding Polytrichum distribution was found on the Consortium of Pacific Northwest Herbaria" website (http://www.pnwherbaria.org/index.php).
A partial listing of Polytrichum mosses east of the Cascade Mountains of Oregon and Washington:
Common Haircap Moss, Polytrichum Moss: Polytrichum commune var. commune (Synonyms: Polytrichum commune var. maximoviczii, Polytrichum commune var. nigrescens, Polytrichum commune var. uliginosum)
Juniper Haircap Moss, Juniper Polytrichum Moss: Polytrichum juniperinum (Synonyms: Polytrichum apiculatum, Polytrichum juniperinum var. waghornei)
Lyall's Polytrichum Moss: Polytrichum lyallii (Synonyms: Polyrichadelphus lyallii, Polytrichastrum lyallii)
Ohio Polytrichum Moss: Polytrichum ohioense (Synonym: Polytrichastrum ohioense)
Awned Haircap Moss, Polytrichum Moss: Polytrichum piliferum
Polytrichum Moss: Polytrichum sexangulare (Synonyms: Polytrichastrum sexangulare, Polytrichum norvegicum)
Polytrichum Moss: Polytrichum strictum (Synonyms: Polytrichum affine, Polytrichum alpestre, Polytrichum juniperinum var. affine, Polytrichum juniperinum var. gracilius)