Summary:
Features include 1) resupinate growth on wood, 2) whitish to light gray or light cream fruitbodies forming patches several centimeters wide, 3) spores that are (5.5)6-7.5(8) x 3.5-4.5 microns and inamyloid, 4) basidia (2)4-spored, and 5) monomitic hyphal system with occasional clamp connections on basal hyphae, but no clamp connections on other hyphae. This species is a member of the Athelia epiphylla complex and is included by Eriksson(1973) in a wider concept of that species, but Julich(3) (1972), Julich(5) (1980), and Ginns(5) (1993) maintain it as separate.

Microscopic:
SPORES (5.5)6-7.5(8) x 3.5-4.5 microns, inamyloid, colorless, thin-walled, with distinct apiculus; BASIDIA mostly 4-spored, rarely 2-spored, 10-16 x 5.5-8 microns, cylindric to clavate; hyphae about 3-8(10) microns wide, the basal hyphae wider than the subhymenial hyphae, thin-walled to somewhat thick-walled (0.2-0.5 microns), occasional clamp connections on basal hyphae, otherwise absent, (Julich(3)), most collections have encrusted hyphae (Eriksson)

Notes:
Athelia salicum has been found in BC, WA, ID, AB, NS, ON, PQ, AZ, CA, CT, IL, ME, MT, NC, NH, NJ, NY, OH, and WI, (Ginns), and Austria, Czechoslovakia, Denmark, Finland, France, Germany, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom, and the USSR, (Julich).