cut flesh has an odor of overripe fruit that intensifies when dry. The European species R. rhodoxanthus has a paler overall color. Another European species, B. permagnificus, has larger spores (13–16 by 5–6.5 μm), weakly decurrent pores, and only associates with oak trees. In addition to its geographic location, the Colombian species B. pyrrhosceles can be distinguished from B. rubroflammeus by its reddish-brown cap (fading to brownish orange in maturity), a brownish-red to deep red stem that is reticulated only at the top, and shallower tubes—up to . B. rhodocarpus, known only from Japan where it grows in deciduous forests, differs primarily in having brownish scales on the cap. Habitat and distribution Boletus rubroflammeus is a mycorrhizal species, and its fruit bodies grow scattered or in groups on the ground under hardwood trees. The fungus fruits in summer and autumn months, and tends to appear after hot weather and heavy rains. Known only from North America, its range extends from New England south to Tennessee, and west to Michigan. It has also been recorded from Mexico. See also List of North American boletes References External links rubroflammeus Fungi described in 1971 Fungi of North America Poisonous fungi