Fruiting body annual, 10-20 cm broad at maturity, rounded to elongate, a mass of overlapping, slender, pendant spines arising from a short, unbranched, sometimes rooted stalk; spines up to 5-6 cm long, the tips pointed, white when fresh, becoming yellowish to yellowish-brown in age; flesh whitish, tough; odor and taste mild.
Spores 5-6 x 4-5.5 µm, nearly round, smooth to slightly roughened, amyloid; spore print white.
Solitary from branch scars of living hardwoods or on fallen logs; fruiting from late fall to mid-winter.
Edible and choice; best when young and the teeth still white to cream.
Of the three Hericiums that occur in the S.F. Bay Area, H. erinaceus is the most recognizable, with a rounded, unbranched, fruiting body composed of pendant, long, slender, white to cream, teeth. Close relatives include Hericium abietis which has a compact, branching structure with shorter, clustered teeth, found on conifer logs, and Hericium ramosum, sparsely branched with short teeth that tend to be arranged in rows, also found on hardwoods.