Lurid and Scarletina Boletes: How to Tell Them from Satan's Bolete

In Ukraine, «dubovyk» (from «dub», oak) is the folk name for several large pored mushrooms, relatives of the porcini, whose pores are neither white nor yellow but orange-red, and whose flesh turns blue, almost black, within a second of being cut. They frighten people who see this for the first time and are prized by those who know them: they are good edible mushrooms, but only when cooked. The two most common are the lurid bolete and the scarletina bolete. Next to them, in the same oak woods, grows Satan's bolete — poisonous and, since 2021, listed in the Red Data Book of Ukraine.

Lurid bolete: a red net on the stem

Lurid bolete (Suillellus luridus, on this site under its Ukrainian name «дубовик звичайний»):

• Cap 8–14 cm, sometimes up to 20, olive brown, ranging from yellowish to dark brown.
• Pores yellow in young mushrooms, later orange-red.
• Stem yellow, covered with a red net — a raised pattern, as if a mesh had been stretched over the stem.
• Flesh yellow; when cut it turns blue instantly, right down to blue-black. In cross-section, just under the tubes, you can see a wine-red line, and at the base of the stem the flesh is reddish.

It grows from June to September under oak, beech and lime, and likes chalky soils.

Scarletina bolete: red dots instead of a net

Scarletina bolete (Neoboletus luridiformis, Boletus erythropus in older field guides, on this site under its Ukrainian name «боровик зернистоногий»):

• Cap 8–20 cm, dark brown, velvety to the touch.
• Pores red.
• Stem yellow, covered with red dots, not a net. This is the main difference from the lurid bolete.
• Flesh yellow, turns blue instantly and intensely.

Unlike the lurid bolete, it likes acidic soils and grows not only under oak and beech but also under spruce, from July to October.

Are these boletes edible?

Both boletes are edible, but only after thorough cooking. Raw or undercooked, they cause digestive upset. The blue colour on the cut surface means nothing bad: it disappears with cooking.

What about alcohol? It is often written that the lurid bolete is poisonous with alcohol, like the common ink cap. This has not been proven. There are isolated reports of reactions resembling the ink cap reaction, and some laboratory data, but coprine — the substance that causes this reaction in the ink cap — has not been found in the lurid bolete, and what exactly might be responsible has not been studied. So the honest wording is this: there is no evidence, but just in case, it is better not to combine these boletes with alcohol.

Satan's bolete: how to tell it apart and why you shouldn't pick it

Satan's bolete (Rubroboletus satanas, in official Ukrainian documents «червоноборовик чортів») resembles the lurid and scarletina boletes with its red pores and the net on its stem. This is how to tell it apart:

• The cap is pale: chalk white, greyish or grey-olive, 6–30 cm. In the lurid and scarletina boletes it is olive brown or dark brown.
• The stem is barrel-shaped, thick, with a red net, often pinkish red in the middle.
• The flesh turns blue weakly and slowly, not instantly and intensely as in the lurid and scarletina boletes.
• The smell of old specimens is unpleasant, like carrion.

A simple basket test: red pores + net on the stem + pale cap = leave it alone.

The toxin of Satan's bolete is a protein called bolesatine. It causes severe nausea, uncontrollable vomiting, abdominal pain and diarrhoea, especially if the mushroom is raw or undercooked. One death under unclear circumstances has been described. Some sources write that thorough cooking neutralises the toxin, but there is no point testing this on yourself — all the more so because in Ukraine picking this mushroom is forbidden.

Ukraine's Red Data Book. In 2021, Satan's bolete was added to the Red Data Book of Ukraine as an endangered species. Along with it came three of its relatives: Rubroboletus rhodoxanthus and R. rubrosanguineus, both endangered, and the wolf bolete (R. lupinus), vulnerable. In Ukraine, Satan's bolete is known from only 15 localities: Crimea and the Vinnytsia, Donetsk, Ivano-Frankivsk, Lviv, Ternopil, Kharkiv and Khmelnytskyi regions. Interestingly, mycologists consider the records of "Satan's bolete" from the Kyiv and Cherkasy regions to be misidentifications: they were red forms of the lurid and scarletina boletes. So if you "see Satan's boletes every year" near Kyiv, they are most likely lurid or scarletina boletes.

More about it in the article Satan's bolete: how to recognise the porcini's poisonous lookalike.

Lurid bolete or bitter bolete

Another mushroom that beginners mistake for these boletes is the bitter bolete (Tylopilus felleus). But its pores are pinkish, not red, its flesh does not turn blue, and the net on its stem is dark. It is not poisonous, just terribly bitter, and it will ruin any dish. How to tell it from the porcini — in the article the bitter bolete.

In short

• Lurid bolete: olive-brown cap, red net on the stem, turns blue instantly. Edible after cooking.
• Scarletina bolete: dark brown, velvety cap, red dots on the stem, turns blue instantly and intensely. Edible after cooking.
• Satan's bolete: pale, chalky-grey cap, barrel-shaped stem with a red net, turns blue weakly and slowly. Poisonous; in Ukraine, listed in the Red Data Book.

When the season for these boletes starts and where to look for them, we cover in the article lurid bolete: when it grows.