Cap 4-10 cm broad, convex, broadly convex at maturity, margin often lobed or wavy, incurved when young; surface dry, at first chamois-like, then more or less glabrous in age, reddish-brown fading slightly at maturity; flesh thick, reddish beneath the cuticle, otherwise yellow, turning blue immediately when cut; odor and taste mild.
Tubes depressed near stipe; pores rusty-red when young, becoming apricot-red at maturity, quickly bruising blue.
Stipe 4-7 cm tall, 1.5-3.0 cm thick, equal to tapered to the base, solid; surface dry, reddish over a yellowish background, not reticulate, flesh yellow, quickly turning blue when cut.
Spores 11-14 x 5-6.5 µm, elliptical, smooth, conspicuously globulate (2-3 globules per spore); spore print olive-brown.
Solitary to scattered under Liveoak (Quercus agrifolia) Madrone (Arbutus menziesii), and species of manzanita (Arctostaphylos); fruiting from late fall to mid-winter.
Unknown, but many red-pored boletes are known to be at least mildly toxic.
Boletus amygdalinus is a handsome bolete distinguished by a reddish-brown cap, orange-red pores at maturity and rapid blueing of all parts of the fruiting body. Boletus erythropus is similar but has a darker, almost chocolate-brown cap and dark red pores at maturity.