Summary:
Features include 1) the resupinate growth on wood of a dingy yellowish brown to pale tan fruitbody, the surface waxy and smooth becoming firmer, uneven and cracked, and the margin indistinct or narrow, concolorous or pallid, 2) elliptic to oblong, inconspicuously verrucose, amyloid spores, 3) tubular gloeocystidia with sulfo-negative to sulfo-positive reaction, and 4) a monomitic hyphal system, without clamp connections. |This taxon was previously considered a Gloeocystidiellum: Ginns(24) and Stalpers(3) use the name Conferticium ravum (Burt) Ginns & G.W. Freeman with the synonyms including Gloeocystidium karstenii Bourd. & Galz. and Gloeocystidium ochraceum Bres. The online Species Fungorum, accessed August 16, 2020, listed them separately and comment that Conferticium ravum is a superfluous name, while listing Conferticium karstenii as a current name with Gloeocystidium karstenii Bourdot & Galzin and Gloeocystidium ochraceum Bres. as synonyms. MycoBank, accessed the same day, listed Gloeocystidium ochraceum Bres. and Gloeocystidium karstenii Bourdot & Galzin as synonyms of Conferticium ravum, following Ginns(24) and Stalpers(3). |Gloeocystidium ochraceum (Fr.) Litsch. is an illegitimate name and a synonym of a different species Conferticium ochraceum (Fr.) Hallenb.

Microscopic:
SPORES (6.0)6.8-8.0(9.0) x (3.8)4.0-4.4(5.2) microns, elliptic, with broadly rounded ends, sometimes flattened adaxially, verruculose, amyloid, the wall thin and easily collapsed, the apiculus small, distinct, and blunt; BASIDIA 4-spored, 24-36 x 5-6 microns, clavate (often collapsed), sterigmata up to 4.5 microns long; GLOEOCYSTIDIA numerous, 35-75 x 6-10(15) microns, "cylindric fusoid to clavate, often with bulbous apex, the wall thin to slightly thickened in some specimens, the contents pale yellow and granular in KOH, sulfo-negative, but possibly weakly positive in some specimens"; HYPHAE monomitic, 2.5-4.0 microns wide, "lacking clamp connections, forming a closely interwoven, indistinct, parallel layer up to 50 microns thick next to substrate"; "subhymenial hyphae indistinct, vertically oriented, agglutinated, appearing pseudoparenchymatous", the walls up to 1.0 micron thick, acyanophilic, (Ginns(24)), SPORES 6-7(8) x 3.5-4.5 microns, elliptic to oblong, finely verrucose (difficult to see in intact spores, best viewed on empty spore coats in Melzer''s), amyloid; BASIDIA 20-30 x 4-5 microns, narrowly clavate, without basal clamp connection, normally 4-spored; GLOEOCYSTIDIA (= pseudocystidia) "numerous, thin-walled, tubular", at first 30-50 x 8-12 microns, then prolonged (70-90 microns) with the thickening of the hymenium, "contents oily, granular, with positive reaction to sulfovanilline", "young gloeocystidia with an apical appendix which later falls off"; HYPHAE monomitic: 2-3 microns wide, thin-walled to somewhat thick-walled, cyanophilous, without clamp connections, "basal layer of horizontal hyphae thin or inconspicuous", subhymenial trama of vertical, densely united hyphae, (Eriksson)

Notes:
Specimens were examined from BC, NB, ON, PE, PQ, SK, YT, AL, AZ, KY, MI, MN, SC, WI; 15 collections were found in the United States; it has also been reported from AK and LA, (Ginns(24)), and Europe including Estonia, Finland, Norway and Sweden, (Eriksson).

Synonyms and Alternate Names:
Athelia borealis (Romell) Parmasto
Merulius borealis Romell