Summary:
Features include 1) resupinate growth on wood, usually of conifers, 2) the fruitbody as inconspicuous, filmy, gray-whitish patches, its surface smooth and delicately farinose, with cystidia visible under a 20x lens, the margin thinning out, 3) spores that are narrowly elliptic to nearly round, smooth, inamyloid, and colorless, 4) cystidia that dissolve in KOH and are thick-walled with a thin-walled head, and 5) a monomitic hyphal system, the hyphae with clamp connections.

Microscopic:
SPORES 4-5 x 3-3.5(4) microns, narrowly elliptic, elliptic to more rarely nearly round, smooth, thin-walled; BASIDIA 4-spored, about 10-15 x 4 microns, somewhat variable in shape from almost conic to stemmed or even lateral but "as a rule subclavate with a median constriction", inamyloid, thin-walled, with basal clamp connection; CYSTIDIA often numerous, 50-90 microns long and about 4-6 microns wide in middle part, narrowing slightly from the base toward the 2.5-4 microns wide neck, "apically widened to a distinct thin-walled head", usually 8-9 microns wide, "capillary lumen gradually expanded to the thin-walled apex", cystidia weakly amyloid, almost grayish, encrusted with amorphous matter that quickly dissolves in KOH but is discernible in water; HYPHAE monomitic, basal hyphae as a rule distinct, 1.5-2.5 microns wide, branching at right angles, thin-walled, "forming together with the subhymenial hyphae a very thin, inamyloid tissue", all hyphae with clamp connections, (Hjortstam), SPORES 4-5(5.5) x 3-3.5 microns, broadly elliptic, smooth, inamyloid, colorless, with droplets; BASIDIA 2-4-spored, 12-14 x 4-5 microns, cylindric-clavate, with basal clamp connection; LYOCYSTIDIA 40-60 microns long, capitate, usually rooting [bifurcate at base], head 6-8 microns wide, neck 2.5-3 microns wide, thick-walled, inamyloid, dissolving in KOH; HYPHAE monomitic, 1.5-2.5 microns wide, septa with clamp connections, (Breitenbach), spores (3)3.5-5.5 x 2-3(3.75) microns, subcylindric to almost pyriform [pear-shaped], smooth, inamyloid, thin-walled; BASIDIA 4-spored, (7)8.5-12(17.5) x 3.5-4.5(5) microns, clavate to subcylindric, stemmed or not, "usually rising perpendicular to basidiophores even when in clumps", sterigmata more or less divergent, up to 4(5) microns long; CYSTIDIA (30)45-65(90) microns long, 2.5-4(5) microns wide near base of stem, thick-walled, slender cylindric, narrowing slightly to a neck width of 2-4 microns, capillary lumen expanding toward tip with thinning of walls to form apical bulb 5-8.5(10) x (4)5-7.5(10.5) microns, cystidia smooth, inamyloid, swelling and dissolving in KOH; SUBICULUM of hyphae 1.5-2 microns wide, usually collapsed or otherwise indistinct, with clamp connections, (Weresub)

Notes:
Tubulicrinis accedens has been found in BC, OR, ON, PQ, CO, IA, IL, IN, MA, and RI, (Ginns). It also occurs in Denmark, Finland, Norway, and Sweden, (Hjortstam), Switzerland and Asia, (Breitenbach), and France (Weresub).