How to tell Ruby bolete from Devil's bolete

Cap 3-7 cm across, hemispherical in young mushrooms, later becoming convex to flat. Color bright red, raspberry-red, carmine, richer when young, fading to brownish-red with age. The surface is velvety and dry, slightly sticky in damp weather. In old mushrooms it often cracks into polygons, revealing a yellow layer under the skin (not red, as in the red cracking bolete).

Cap 8–30 cm across, massive, globular in young mushrooms, then cushion-shaped. Surface dry, matte, pale gray or grayish ocher, with no bright coloring — it contrasts with the red pores. In old mushrooms the cap is often blotchy.

The hymenophore is made of tubes attached to the stem. Color yellow when young, turning yellow-olive with age. The pores are small and stain strongly blue when pressed. Spore print olive-brown.

Pored hymenophore. Pores bright red or blood-red — the mushroom's most noticeable feature. When pressed they turn blue very intensely and quickly. Tubes yellow or yellow-green near the stem.

Stem 4-7 cm tall, 0.8-1.5 cm thick, cylindrical, often thickening toward the base. Color yellow at the top, with distinct reddish-brown lengthwise streaks and a delicate reddish fibrous net in the lower half. In old mushrooms the stem is redder.

Stem 5–15 cm tall, 4–10 cm thick, massive, globular or barrel-shaped. Covered with a characteristic bright red net pattern on a yellow background — especially in the upper part. Turns blue when pressed.

The flesh is thin, soft and yellow, and in the lower part of the stem with a noticeable bright yellow or yellow-orange spot when cut lengthwise — a diagnostic feature of the species. When cut, it stains strongly blue (within 30-60 sec).

Flesh yellowish, very firm, heavy. Turns blue in a flash when cut — the reaction comes within 3–5 seconds and is far more intense than in edible bluing species. In old mushrooms the flesh has an unpleasant smell.

Faint, pleasant and mushroomy, with no distinct notes.

In young mushrooms the smell is unobtrusive or absent. In mature mushrooms it is rather unpleasant, rotten or ammonia-like, especially noticeable in hot weather. The smell gets stronger when dried.