Rheubarbariboletus armeniacus

Species characteristic of broadleaf woodlands, especially oak or chestnut, with a hemispherical to convex pileus 4 to 10 cm in diameter, orange-pink to reddish; pores and tubes lemon yellow to greenish yellow; yellow flesh blueing upon cutting, especially in the tubes and upper stipe; fruity odor and sweet taste.

Cuticle filamentous, with cylindrical hyphae, interwoven, 6 to 11 µm wide, with abundant encrusting yellowish-brown intracellular pigment, septate with simple septa.

Cheilocystidia fusiform to lageniform, hyaline, thin-walled, 25 to 45 µm long and 8 to 11 µm wide.

Pleurocystidia identical in morphology to cheilocystidia, 40 to 80 µm long and 9 to 12 µm wide.

Basidia clavate, 30 to 45 µm long, 9 to 12 µm wide, containing granular matter of small oil droplets inside, simple-based and generally four-spored.

Spores cylindrical to fusiform, smooth- and thick-walled, yellowish under the microscope, with a pointed, curved end bearing the apiculus, 10.5 to 12.5 µm long, 4.5 to 5.5 µm wide, with faint oil droplet content inside.