Summary:
Features include 1) resupinate growth on wood (or bent out to form a narrow black cap), 2) a light ochraceous to light grayish spore-bearing surface, 3) a tough hard consistency, 4) a coconut odor, 5) spores that are narrowly elliptic, smooth, inamyloid, cyanophilic, and colorless, 6) inflated to clavate gloeocystidia, not or only slightly projecting, smooth, sometimes filled with yellowish material, and 7) a dimitic hyphal system, the generative hyphae with clamp connections. Eriksson notes that there are some differences between American and European material: 1) in Europe it only grows on Picea abies whereas in North America it prefers hardwoods, 2) the European fruitbodies are thinner, 0.1cm compared to 0.2-0.3cm or more in North America, 3) the spore-bearing surface in Europe is grayish white (ash-colored), in North America as a rule brighter (e.g. light yellowish ochraceous), 4) spores are generally somewhat larger in North American specimens, (Eriksson).

Microscopic:
SPORES 4.5-5.5 x 2.5-3 microns, narrowly elliptic to subcylindric, smooth, inamyloid, cyanophilic, thin-walled; BASIDIA narrowly clavate, usually 25-30 x 5 microns, 4-spored with basal clamp connection; GLOEOCYSTIDIA (pseudocystidia) "very numerous, especially in the subhymenial trama but also in the subiculum": when very young, "they originate from the subiculum and extend into the hymenium, later new gloeocystidia develop in the hymenium as long as the thickness increases", "usually ovate to ellipsoid, 7-15 microns wide, rarely more, and 30-40 microns long in the hymenium and the subhymenial trama, longer and narrower in the subiculum", in thin sections "they appear empty but are normally filled with oildroplets", they remain as rounded vesicles rather than lengthening as in Gloeocystidiellum, in many specimens some of them are filled with a homogeneous yellow substance; HYPHAE dimitic: sparse thick-walled skeletal hyphae 1.5-3 microns wide, especially in the subiculum, and thin-walled richly branched generative hyphae, 2-3.5 microns wide, with clamp connections, the hyphae in general are agglutinated, and hyphal direction is horizontal in subiculum and vertical in subhymenium, (Eriksson), SPORES 4.5-5 x 2-3 microns, elliptic, smooth, inamyloid, colorless; BASIDIA 4-spored, 35-40 x 4-5 microns, narrowly clavate, with basal clamp connection; GLOEOCYSTIDIA not or only slightly projecting, 20 x 15 microns or 40-60 x 8-10 microns, clavate to fusiform or nearly spherical, smooth, sometimes filled with yellowish material; HYPHAE dimitic: generative hyphae 2-3.5 microns, thin-walled, septa with clamp connections, skeletal hyphae 1.5-3.5 microns wide, thick-walled, strongly branched, (Breitenbach)

Notes:
Cystostereum murrayi has been reported from BC, OR, ID, NB, NF, NS, ON, PQ, CT, FL, IA, IL, LA, MA, ME, MI, MN, NH, NY, PA, RI, TN, VA, VT, WI, and WV, (Ginns). It occurs in Norway and Sweden, (Eriksson), and Switzerland, Germany, and Asia, (Breitenbach).

Synonyms and Alternate Names:
Coriolus planellus Murrill