Summary:
Tubulicium vermiferum is identified easily under the microscope by its conic cystidia sheathed in narrow dendritic hyphae, and spores that are curved or flexuous [wavy] and pointed more at one end than the other. Features include 1) resupinate growth on a variety of genera, 2) a white to cream-yellow fruitbody, smooth but often cracked, the surface bristly under a lens, the margin abrupt or indistinct, 3) spores that are sigmoid or flexuous-navicular, pointed at both ends but more obtuse at the apiculate end, smooth, inamyloid, and colorless, 4) cystidia that are conic, many-rooted, thick-walled with a capillary lumen, strongly encrusted and also covered with narrow, dendritic hyphae, the cystidial walls slightly amyloid, partly dissolving in KOH, and 5) a monomitic hyphal system, the hyphae somewhat agglutinated, with clamp connections.

Microscopic:
SPORES "sigmoid, flexuose-navicular or vermicular, smooth, thin-walled", generally 20-25 x 3.5-4 microns; BASIDIA 4-spored, 25-35(40) x 10-12 microns, terminal, thin-walled, subclavate to more or less stemmed, sterigmata fairly stout; CYSTIDIA narrowly conic to cylindric, usually 80-100 microns long and 8-12 microns wide near base, "thick-walled and slightly amyloid, with a narrow capillary lumen, strongly encrusted and besides also covered with narrow, dendroid hyphae", only 0.5-1 micron wide; HYPHAE monomitic, 2-2.5 microns wide, "thin-walled or with slight wall thickening, somewhat agglutinated", septa with clamp connections, (Hjortstam), SPORES (10)15-25(30) x (3)4-5.5 microns, flexuous-navicular, usually somewhat pointed toward the distal end, smooth, inamyloid, thin-walled; BASIDIA 20-45 x (5)8.5-11.5 microns, sinuately clavate, usually 4-spored, the sterigmata 6.5-7.5 microns long, 2.5 microns wide at base, fleshy, divergently arcuate; CYSTIDIA 75-185 microns long, 10-25 microns wide just above base, conic, narrowing to more or less pointed apex, "typically sheathed in dendroid branching hyphae" 0.75-1.5 microns wide, sometimes also encrusted, cystidial walls "lightly but positively amyloid", thick, 3.5-7 microns wide, "dissolving in KOH, though apices and outer layer of wall often left standing after KOH action", "lumina usually fairly broad at base, frequently becoming capillary well below the middle, often completely obscured apically, though sometimes not narrowing to capillarity even at the tip"; HYPHAE in subiculum indistinct, perhaps agglutinated, apparently with frequent clamp connections, some with thickened walls dissolving in KOH, others thin-walled, 2-2.25 microns wide, (Weresub(3)), SPORES (10)15-25(30) x (3)4-5.5 microns, flexuous-navicular, pointed at both ends, but broader at the apiculate end, smooth, inamyloid, colorless; BASIDIA 4-spored, 20-45 x (5)8.5-11.5 microns, sinuately cylindric to subclavate, "borne directly on the horizontal hyphae, the base bifurcate, often obscure, or occasionally terminal on short upright hyphae" and subtended by a clamp connection, sterigmata 6.5-7.5(10.5) x 2.5 microns, divergent, arcuate; CYSTIDIA 75-185 x 10-25 microns, conic, "perpendicular to the horizontal hyphae, the base several-rooted, the walls thick, lamellate, externally covered with a roughened crystalline shell" or more often sheathed by dendritic hyphae about 1 micron wide; HYPHAE mostly parallel to the substrate, septa with clamp connections, 1.5-2.5 microns wide, conglutinate or the walls becoming gelatinized, (Liberta)

Notes:
Tubulicium vermiferum has been found in BC, CA, and FL, (Ginns). It also occurs in Norway and Sweden, (Hjortstam), and HI, Denmark, France, and New Zealand, (Liberta).