Rubroboletus pulcherrimus—known as Boletus pulcherrimus until 2015—is a species of mushroom in the family Boletaceae. It is a large bolete from Western North America with distinguishing features that include a netted surface on the stem, a red to brown cap and stem color, and red pores that stain blue upon injury. Until 2005 this was the only bolete that has been implicated in the death of someone consuming it; a couple developed gastrointestinal symptoms in 1994 after eating this fungus with the husband succumbing. Autopsy revealed infarction of the midgut. Taxonomy American mycologists Harry D. Thiers and Roy E. Halling were aware of confusion on the west coast of North America over red-pored boletes; two species were traditionally recognised—Boletus satanas and Boletus eastwoodiae. However, they strongly suspected the type specimen of the latter species was in fact the former. In reviewing material they published a new name for the taxon, which Thiers had written about in local guidebooks as B. eastwoodiae, as they felt that name to be invalid. Hence in 1976 they formally described Boletus pulcherrimus, from the Latin pulcherrimus, meaning "very pretty". It was transferred to the genus Rubroboletus in 2015 along with several other allied reddish colored, blue-staining bolete species such as B. eastwoodiae and B. satanas. Description Colored various shades of olive- to reddish-brown, the cap may sometimes reach in diameter and is convex in shape before flattening at maturity. The cap surface may be smooth or velvety when young, but may be scaled in older specimens; the margin of the cap is curved inwards in young specimens but rolls out and flattens as it matures. The cap may reach a thickness of when mature. The adnate (attached squarely to the stem) poroid surface is bright red to dark red or red-brown and bruise dark blue or black; there are 2 to 3 pores per mm in young specimens, and in maturity they expand to about 1 or 2 per mm. In cross section, the tubes and flesh are yellow. The tubes are between long, while the angular pores are up to 1 mm in diameter; pores can range in color from dark red in young specimens to reddish brown in age. The pores will stain a blue color when cut or bruised. The solid, firm stem is long and thick—up to in diameter, at the base before tapering to at the top. It is yellow