CAP: (6-15.5 cm) wide, convex to broadly convex, becoming nearly plane in age; surface smooth, dry, slightly sticky when wet, pale lemon-yellow splashed irregularly with brick to bright rusty red, finally brick-red overall; flesh white, not blueing when bruised or cut, changing to olive-gray with the addition of FeSO₄; odor and taste not distinctive.

PORE SURFACE: white when very young, soon turning creamy lemon-yellow, finally olive-brown in age, staining pinkish cinnamon when bruised; pores circular, 2-3 per mm.

STALK: (5-15.5 cm) long, (2.5-3.5 cm) thick, equal or enlarging downward, sometimes bulbous, pinkish tan to cinnamon-brown beneath a white reticulum on the upper one-third or more, base whitish, solid; partial veil and ring absent.

SPORE PRINT: yellow-brown.

MICROSCOPIC FEATURES: spores 11-16 x 5-7 μm elliptic to spindle-shaped, smooth, pale brown.

FRUITING: solitary to scattered under mixed conifers and hardwoods; July-October; uncommon to rare.

EDIBILITY: edible, choice.

COMMENTS: Boletus edulis var. aurantio-ruber (edible, choice) is very similar, with a cap that is rusty red overall or ochraceous on the margin, is often wrinkled, lacks the pale lemon-yellow ground color, and has a pale yellow pore surface that becomes olive-yellow, then brownish yellow to brown in age. Other varieties of Boletus edulis (edible, choice) are usually larger, have reddish brown to yellowish tan caps, and also lack the pale lemon-yellow ground color and creamy lemon-yellow pore surface. (The illustrations of Boletus edulis shown in Taming the Wild Mushroom and Edible Wild Mushrooms of North America are actually Boletus chippewaensis.)

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