Epithet = named after Swiss mycologist Jacob Gabriel Trog. Genus = diminutive of Trametes.
Polypore with sessile brackets but can be effused-reflexed or more rarely resupinate.
Key characters are the large pores and the coarsely hispid cap surface: long, stiff, erect hairs, turning brown; context whitish.
Bracket is hard, rigid, up to 6 to 12 cm wide and projecting 2 to 4 cm. Upper surface hairs are pale to ochre-brown.
Context below hairs whitish to cream, darkening with KOH.
Context is lacking a black zone and has no sharp division between the context and the hairy covering.
Tubes pale, thin-walled, and continuous with lower context; tube layer up to 1 cm thick.
Pore surface pale to honey-colored (darker on end view); pores angular to elongated, large, 1 or 2 per mm; pore surface can be uneven from lacerate (toothy) pore mouths.
In age or when over-wintering the surface hairs can wear down but typically streaks (agglutinated hairs) are evident.
Hyphal system trimitic with clamped generative hyphae, thick-walled skeletal hyphae, and branching binding hyphae.
Skeletal hyphae cyanophilous (dark blue with cotton blue stain) and metachromatic (bluish green-lilac with cresyl blue stain).
Basidiospores cylindrical 7–9 × 2.5–4 µm.
Trametella gallica is most similar and also widespread but the context is rusty to umber brown and the spores are larger.
Trametopsis cervina has hairs that are less coarse, coloration generally more yellow, brackets larger up to 21 × 5 cm; context not duplex.
Trametes hirsuta has hirsute surface that has weak zones of gray, sometimes yellowish; pores are smaller and turn gray; pores round and surface even, not lacerate.
Trametes villosa (southern USA) is thinner and more flexible.
Some Antrodia species are mistakenly identified as T. trogii but Antrodia lack the coarse hispid hairs on the cap; pores are smaller in some species.
White rot of dead hardwoods. Most often reported from quaking aspen but also found on other trees including willow, maple, birch, beech, elm, and oak.
Spring to fall, overwinters.
Widespread in North America but reports are more common in the northeastern states, from Minnesota to Maine, and Ontario. Found in Europe, where it is threatened in some northern countries; Russia, and China.
Chicago Region status
Uncommon. One historic record and a dozen recent collections.
Historic collections and a few more recent ones, then collected once a year in the last seven years.
Taxon Details and Links
Acta Societatis Botanicorum Poloniae 37: 126 (1968)
in Trog, Mittheil. d. schweiz. Naturf. Ges. in Bern 2: 52 (1850)
Mala flora grzybów. Tom I: Basidiomycetes (Podstawczaki), Aphyllophorales (Bezblaszkowe). Bondarzewiaceae, Fistulinaceae, Ganodermataceae, Polyporaceae 1: 230 (1974)
location? ; on Fraxinus (ash).
This species has also been placed in Cerrena and with other synonyms in Daedalea, Inodermus, Microporus, and Polyporus. Authors have been unsure where to place it between the Trametes group with white context and the Coriolopsis–Trametella group with brown context. DNA revealed it was related to various Coriolopsis s.l. rather than Trametes. Unfortunately the type species for Coriolopsis is a Trametes. Among the orphaned Coriolopsis s.l., T. trogii is paired with C. gallica, the type species for Trametella. These two species may become part of Funalia but this determination awaits sequencing the type species for Funalia.