or yellow-brown in color and bears a network of red reticulations on the upper 2/3 of its length. The spore print is olive-brown. The taste of the flesh is reportedly mild, and the odor indistinct, or "slightly fragrant". Microscopic characters The spores are spindle-shaped or elliptical, thick-walled, smooth, and have dimensions of 13–16 by 5.5–6.5 μm. The basidia, the spore-bearing cells, are club-shaped (clavate), attached to 1 to 4 spores, and have dimensions of 35–90 by 9–12 μm. The cystidia (sterile, non-spore-bearing cells found interspersed among the basidia) in the hymenium have dimensions of 33–60 by 8–12 μm. Clamp connections are absent in the hyphae of B. pulcherrimus. Similar species Although the relatively large fruiting bodies of R. pulcherrimus are distinctive, they might be confused with superficially similar species, such as Rubroboletus eastwoodiae; the latter species has a much thicker stalk. Another similar species is R. haematinus, which may be distinguished by its yellower stem and cap colors that are various shades of brown. Its darker cap and lack of reticulation on the stipe differentiate it from R. satanas. Neoboletus luridiformis grow with oaks but is smaller and have non-reticulate stipe. Distribution and habitat Rubroboletus pulcherrimus is found in western North America, from New Mexico and California to Washington, and may feasibly occur in British Columbia, Canada. One source notes it grows at low altitudes in the Cascade Range and Olympic Mountains; another claims it grows at high elevations, over . Fruiting in autumn, it grows singly or in groups (although another source claims "never in groups") in humus in mixed woodlands. In the original publication describing the species, Thiers and Halling note that it is associated with forests containing tanbark oaks (Lithocarpus densiflora), Douglas fir (Pseudotsuga menziesii), and Grand Fir (Abies grandis). Smith and Weber mention increased fruitings after warm heavy fall rains following a humid summer. Toxicity In general, blue-staining red-pored boletes should be avoided for consumption. Thiers warned this species may be toxic after being alerted to severe gastrointestinal symptoms in one who had merely tasted it. Years later, in 1994, a couple developed gastrointestinal symptoms after eating this fungus and the husband died as a result. A subsequent autopsy revealed that the man had suffered an infarction of the midgut. Rubroboletus pulcherrimus was the only bolete that had been implicated in the death of someone consuming it, It is known to contain low levels of muscarine,