Summary:
Features include 1) resupinate growth, usually on wood, 2) a green to dull brown, cobwebby to mould-like fruitbody, the surface colliculose to sometimes smooth, the margin and subiculum yellowish brown to ferruginous brown, the margin fringed, 3) spores appearing 3-lobed or 4-lobed to irregular, echinulate, and pale brown, 4) fungal tissue normally assuming a green, bluish green, or purple color in KOH, basidial contents becoming green to purple, the basidia often and sterigmata sometimes with transverse septa, and 5) a dimitic hyphal system, with 3 types of subicular hyphae.

Microscopic:
SPORES 7-8 microns in diameter, appearing 3-lobed or 4-lobed to irregular, echinulate, pale brown; fungal tissue normally assuming a green, bluish green, or purple color in KOH; BASIDIA 4-spored, 40-45 x 6-8 microns, clavate, with clamp connection at base, often with transverse septa, "sterigmata up to 5 microns long and sometimes with septa", "basidial contents becoming green, bluish green, or purple, a brown incrusting material on basidial walls sometimes present but tends to dissolve, producing a similarly colored diffusate" [quotation in italics, it is not specified whether this is applying to KOH preparations]; SUBHYMENIAL HYPHAE 2-3(4) microns wide, colorless, thin-walled, septate, with clamp connections frequent, sometimes with brown encrusting material; SUBICULAR HYPHAE of three types 1) some generative, 3-4(5) microns wide, citrine to yellowish brown, (contents frequently becoming dark ocher), thick-walled, septate, with clamp connections frequent, 2) some generative 4-6(7) microns wide, pale citrine, wall thickening apparent, septate, clamp connections rare, rarely branched, 3) some skeletal, 2-2.5(3) microns wide, citrine, thick-walled, rarely branched, normally aseptate; CORDONS of 2 types: 1) some up to 90 microns wide, brown, composed of generative hyphae that are 2-3 microns wide, with clamp connections, 2) some up to 30 microns wide, "citrine, composed of skeletal hyphae" that are 2-2.5 microns wide, citrine, citrine, thick-walled, and with rare septa, (Larsen)

Notes:
Tomentella ferruginea has been found in BC, WA, ID, MB, NB, NF, NS, ON, AZ, CO, FL, IA, KY, MA, MD, MI, MN, MT, NH, NM, NY, OH, SC, TN, VA, VT, WI, and WV, (Ginns), as well as Costa Rica, Czechoslovakia, Denmark, France, Germany, Hungary, Netherlands, Sweden, United Kingdom, Tunisia, India, and New Zealand, (Larsen).

Synonyms and Alternate Names:
Leptopodia albella (Quel.) Boud.