Characters of basidiocarps and cultures of 14 Poria spp. (wood-inhabiting Hymenomycetes) from western North America are described and illustrated. Substrata and geographical distribution are given. The spp. are Poria albobrunnea (Rom.) Baxter, P. albolutescens (Rom.) Egel., P. alpina Litsch., P. aneirina (Sommerf.) Cke., P. bombycina (Fr.) Cke., P. carbonica Overh., P. radiculosa (Pk.) Sacc, P. reticulata (Fr.) Cke., P. rhodella (Fr.) Cke., P. sericeomollis (Rom.) Baxter, P. taxicola (Pers.) Bres., P. vaillantii (DC. ex Fr.) Cke., P. vaporaria (Pers. ex Fr.) Cke., and P. xantha (Fr.) Cke. Nine of these are associated with common brown rots, and 5 with white or indistinct types of rots. Four spp. cause deterioration of various wood products.