CAP: (5-16 cm) wide, convex, becoming broadly convex to nearly flat; surface finely velvety when young, dry, not sticky, dark to pale brick-red, fading to dull rose or sometimes dingy cinnamon in age, quickly staining blue when bruised; flesh pale yellow, blueing instantly when cut or bruised, instantly yellow with KOH, turning yellow-brown with FeSO₄; odor and taste not distinctive.

PORE SURFACE: yellow when young, becoming duller or browner in age, blueing instantly when bruised; pores circular, 1-2 per mm.

STALK: (8-12 cm) long, (1-3.5 cm) thick, equal or enlarging slightly downward, solid, mostly yellow but often tinged pink or red near the base, occasionally finely reticulate only at the very top, quickly staining blue when bruised; flesh bright yellow, quickly staining blue when exposed; partial veil and ring absent.

SPORE PRINT: olive-brown.

MICROSCOPIC FEATURES: spores 10-13 x 3.5-4.5 μm, suboblong to slightly ventricose, smooth, pale brown.

FRUITING: scattered or in groups on the ground in woods, usually hardwoods; July-September; occasional to fairly common.

EDIBILITY: poisonous.

COMMENTS: can cause severe gastrointestinal upset. Compare with Boletus miniato-olivaceus (poisonous), which has a bright brick-red to bright rose-red cap that becomes olivaceous in age. Also compare with Boletus miniato-pallescens (edibility unknown), which has a red to brick-red cap that fades to reddish orange or orange-yellow.

From Mushrooms of Northeastern North America Alan E. Bessette, Arleen R. Bessette, & David W. Fischer  Copright © 1997 Syracuse University, ISBN 0-8156-0388-6