[2] Other similar red-pored, bluing boletes from North America, including Rubroboletus eastwoodiae, Boletus luridiformis, and B. subvelutipes, can be distinguished from S. amygdalinus either by the color of the cap, the degree of reticulation (a network of raised ridges) on the stipe, or by location.

The species was first named Boletus puniceus by Harry D. Thiers in 1965, based on specimens he found in Napa County, California, on 23 November 1963.

[3] In 1975, Thiers changed the name to Boletus amygdalinus (a nomen nudum) as he discovered that the epithet had already been used for a different bolete found in Yunnan, China,[2] published in 1948.

[7] Suillellus amygdalinus is a large solid mushroom with a convex to somewhat flattened, irregular cap that can reach diameters of 6 to 12 cm (2.4 to 4.7 in) at maturity.

[3] The flesh is 1 to 2 cm (0.4 to 0.8 in) thick, and yellow in color, but like all parts of the mushroom, will stain blue immediately upon bruising or cutting.

The poisonous European species Rubroboletus satanas and its North American counterpart R. eastwoodiae have lighter colored caps and a reticulate pattern on the stipe.

Unlike S. amygdalinus, however, B. luridiformis has a dark brown to nearly blackish-brown cap, and a yellow stipe with a dense covering of red pruina (dots).

The fungus has been reported from low-elevation hardwood forests composed of live oak, manzanita and madrone in California,[9] and Oregon.