Fruiting body annual or short-lived perennial, sessile, 4-10 cm broad, 1.5-2 cm thick, resupinate, forming a fan-shaped, slightly convex, thin bracket, several often sharing a common base; margin entire, undulate or lobed, the latter often the result of emerging new growth; surface at first matted-hairy, becoming smooth, bumpy or warted, sometimes concentrically furrowed, mahogany-brown to dark-brown, usually pinkish at the margin when fresh, nearly black towards the base; flesh thin, pliant, dingy pink when fresh, woody, and dingy pinkish-brown in age, blackening in KOH; odor and taste mild.
Pores 3-4 per mm, pale to dark pink, pinkish-brown in age, tubes multi-seried, 2-3 mm long, dingy pink.
Spores 5.5-7.0 x 1.5-2.0 µm, smooth, allantoid (curved cylindrical); spore print off-white.
Scattered or forming overlapping shelves on downed conifer wood; fresh fruitings emerging from late fall to mid-winter.
Though not the most common of our local conks, Fomitopsis cajanderi is easily the prettiest. The mahogany-brown to almost black shelves of fresh Fomitopsis cajanderi with contrasting rose-pink margins and pores are a visual delight. In age the pink color becomes muted but specimens are still easily recognized.