Tomentella ferruginea

On decaying wood or bark on the ground, with completely resupinate fruit bodies, easily separable from the substrate, of a rusty-brown (ferruginous) color, turning greenish upon application of KOH, with a diffuse and poorly defined growing margin.

Dimitic hyphal system, with thick-walled skeletal hyphae 3.5 to 4.5 µm in diameter, with brownish intracellular pigment, aseptate, and generative hyphae thin- to slightly thick-walled, hyaline, identical in width to skeletal hyphae, septate, with clamped septa.

Without cystidia.

Basidia subcylindrical to slightly clavate, 25 to 45 µm long, 4 to 6 µm wide, with basal clamp connections, and with two or four sterigmata.

Spores ellipsoid, irregular in outline, thick-walled, yellowish-brown under the microscope, echinulate, with short spines up to 1 µm high, 6.5 to 8 µm long, 5.5 to 6.5 µm wide, inamyloid in Melzer's reagent.