Trametes betulina (formerly Lenzites betulina), sometimes known by common names gilled polypore, birch mazegill or multicolor gill polypore, is a species of fungus.
Although it is a member of the Polyporales order, its fruiting bodies have gills instead of pores, which distinguishes it from the superficially similar Trametes versicolor or Trametes hirsuta. Research has shown that it has several medicinal properties, including antioxidant, antimicrobial, antitumor, and immunosuppressive activities.
Trametes betulina would be just another polypore, except that the the spore-bearing surface is gill-like, not poroid. Despite this apparent similarity to fleshy, gilled, mushrooms, Trametes betulina is a polypore with the characteristic leathery toughness one would expect of a member of this group. Another polypore, Trametes versicolor has a remarkably similar, zonate, tomentose, upper surface, but is easily distinguished by a poroid hymenium. Less common than Trametes betulina is Gloeophyllum sepiarium, which also has a gill-like hymenium, but is rusty-brown in color, and grows on conifers as opposed to hardwoods. Fruiting body annual or short-lived perennial, 2-10 cm broad, 0.5-2.0 cm thick, at first resupinate, then forming sessile, fan-shaped, tiered brackets or occasionally rosettes emanating from a common base; surface tomentose, concentrically-zoned, often multi-colored, cream, pale-buff, dingy yellow-brown, or greyish-brown, in age sometimes green from encrusted algae; flesh thin, pliant, becoming tough, cork-like, white, unchanging; odor and taste mild. Spore print white.
Scattered to clustered in overlapping shelves on hardwood logs, but not limited to birch as the the species name would suggest; fruiting from early to late winter.
Research has shown that it has several medicinal properties, including antioxidant, antimicrobial, antitumor, and immunosuppressive activities.