Summary:
Features include 1) resupinate growth on wood, 2) a cobwebby to cottony or floccose fruitbody (usually mould-like), that is dark brown to dull grayish blue, granulose to colliculose, the sterile margin sometimes paler, the subiculum fibrous, dark brown or sometimes dull grayish blue, 3) spores that are round to irregularly round, spiny, and dull brown, 4) basidia 4-spored to rarely 5-spored or 6-spored, sometimes with transverse septa, 5) subicular hyphae of 2 types but mostly the type that is dull brown, frequently with clamp connections, wall thickening apparent, and with dull brown encrusting material giving the walls a rough or spinulose appearance. The online Species Fungorum, accessed September 9, 2012, listed this as a synonym of Tomentella lilacinogrisea Wakef., Trans. Br. mycol. Soc. 49(3): 360 (1966).

Microscopic:
SPORES 5-6.5(7.5) microns in diameter, round, nearly round, irregularly round, or rarely irregular when mature, "aculeolate to echinulate, sometimes aculeate, walls dull brown"; BASIDIA 4-spored to rarely 5-spored or 6-spored, 20-35 x 5.5-7.5 microns, clavate, with clamp connection at base, infrequently with transverse septa; SUBHYMENIAL HYPHAE 3-4.5 microns wide, pale to dark brown near the subiculum and paler toward the hymenium, thin-walled, with clamp connections, often encrusted as in subicular hyphae, in some specimens a bluish to greenish diffusate is apparent in KOH; SUBICULAR HYPHAE of 2 types: 1) some 3-5(6.5) microns wide, dull brown, frequently with clamp connections, wall thickening apparent, with dull brown encrusting material giving the walls a rough or spinulose appearance, walls rarely smooth, 2) some rare 2-4 microns wide, pale to dark brown, "thick-walled with the lumen sometimes not evident", usually septate without clamp connections, "with brown encrusting material giving the walls a rough or spinulose appearance"; CORDONS infrequent or rare, up to 35 microns wide, dark brown, individual hyphae 2-4.5 microns wide, brown, with clamp connections, often encrusted as above, (Larsen)

Notes:
Tomentella neobourdotii has been found in BC, ON, PQ, AZ, KY, MA, MI, MT, NC, NM, NY, TN, and WI, (Ginns), as well as Czechoslovakia, Denmark, Finland, France, Germany, Macedonia, Sweden, and the United Kingdom, (Larsen).