Summary:
Features include 1) resupinate growth on wood and other plant remains, 2) a white to cream fruitbody forming thin, membranous patches several centimeters across, 3) spores that are 6-10 x 2.5-5 microns for the wide concept of the species, (6-7.5 x 2.8-3.2 microns for the narrower concept), more or less elliptic, smooth, and inamyloid, 4) (2)4-spored basidia, and 5) a monomitic hyphal system, the hyphae with occasional clamp connections in the basal hyphae but none in subhymenium or on basidia. The description of Eriksson is for a wider concept of the species than that of Julich(1972), and includes Athelia salicum Pers. as well as several other species not recorded from the Pacific Northwest, but according to Breitenbach(2), Julich & Stalpers(1980) include several species in A. epiphylla, including A. salicum Pers. (Ginns(5) however maintains A. salicum Pers. as separate.)

Microscopic:
SPORES 6-10 x 3-5 microns, subcylindric, narrowly elliptic or oval; BASIDIA usually 4-spored, 15-20 x 5-6 microns; SUBHYMENIAL HYPHAE 3-5 microns wide and without clamp connections, BASAL HYPHAE somewhat wider and with clamp connections, (Eriksson), SPORES (5)6-8 x 2.5-3.5 microns, elliptic with obtuse base, smooth, inamyloid, colorless; BASIDIA 4-spored or more rarely 2-spored, 18-22 x 4.5-6.5 microns, without basal clamp connection; CYSTIDIA not seen; HYPHAE monomitic, BASAL HYPHAE 3.5-6 microns wide, with occasional clamp connections, SUBHYMENIAL HYPHAE 2.5-4.5 microns wide, some coarsely encrusted, without clamp connections, (Breitenbach), SPORES (5.5)6-7.5(8) x 2.8-3.2 microns, BASIDIA (2-)4-spored, 13-18 x 5-8 microns, (Julich)

Notes:
Athelia epiphylla has been found in BC, ID, AB, NS, NT, ON, PQ, AZ, CA, CO, IL, MA, MT, NY, OH, and UT, and for A. salicum also WA, CT, ME, NC, NH, NJ, and WI, (Ginns). Distribution includes Venezuela, Austria, Czech Republic, Denmark, Estonia, Finland, France, Germany, Latvia, Netherlands, Norway, Spain, Sweden, Switzerland, United Kingdom, Turkey, USSR, and for A. salicum also Poland, (Julich).

Synonyms and Alternate Names:
Pellicularia ansosa H.S. Jacks. & D.P. Rogers