Boletus discolor

Cap bruises black. Blue-staining, orange-red pores age yellow from the edge in. Yellow stem w/ fine red-brown dots stains blue-black or browns w/age.

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Genus: Boletus (will probably change – see Science Notes)

  • Genus 2: Likely to become Sutorius or Neoboletus

Species: discolor (will probably change – see Science Notes)

  • Species 2: subluridellus
  • Species 3: erythropus ssp. discolor
  • Species 4: luridiformus ssp. discolor

Common Name: Red Mouth Bolete

Tells: Cap bruises black. Blue-staining, orange-red pores age yellow from the edge in. Yellow stem w/ fine red-brown dots stains blue-black or browns w/age.

Other Information: Pale yellow flesh quickly blues. Cap color starts orangey, fades toward yellow, and then darkens to brown from the middle out. A common species from the Mason-Dixon line up. No netting distinguishes from B. luridus, & no red hairs at the stem base distinguishes from the hemlock loving B. subvelutipes. B. luridiformis has a darker cap and darker yellow flesh than B. discolor, but chemical tests are required to conclusively distinguish the two (they have distinctly different reactions to Ammonia and KOH).

Science Notes: The European species formerly known as Boletus discolor, and Boletus luridiformis, Boletus erythropus, and Boletus queletii have been merged into a single species that is now called Suillellus (maybe Neoboletus) queletii. Boletes of Eastern North America follows this by merging the American “discolor” into “luridiformis” (using Neoboletus as the genus) and then continuing to use the European name until a replacement is settled. The bottom line is this: it is a beautiful mushroom with massive flexibility in how it appears.

Here’s the problem: are we justified in doing the same for the North American mushrooms known by (some) of those species names? We can be pretty sure they are not the European queletii and unpublished amateur DNA work shows that the oak-loving ones do indeed follow the same pattern – massive morphological flexibility with the same DNA – but what is the appropriate American name? Especially when different reactions to both Ammonia and KOH have been reported? They probably are the same thing… but we cannot say that with enough confidence to justify removing entries that still appear in the books, or to merge them without a proper, peer reviewed article in a reputable scientific journal. For this reason discolor, luridiformis and subluridellus still appear here under separate names even though they are likely to end up being merged into two species, and maybe even one mega-species. FWIW, those same DNA tests show that the hemlock loving B. subvelutipes really is a separate species. Stay tuned for new developments.

There is also some question about whether the Genus Suillellus should be merged with Neoboletus… but that is a whole different fight, lol. Suffice it to say they are close relatives.

One hopes the science will catch up to both of these, along with the other hard-to-distinguish red pored, blue staining lookalikes such as , B. subluridus and B. flammans, not to mention the one now known as Suillellus luridus, the several moved to Rubroboletus, and the brown-pored blue-stainers vermiculosus and vermiculosoides.

Edibility: The traditional instruction in America was clear: “Avoid the red-pored blue-stainers like this one because they are known sick makers.” That came under question beginning in the 2010’s as DNA evidence proved that these mushrooms are quite distinct from the Rubroboletus and Suillellus genera that contain the true “Satans Boletes”. For what it’s worth, the lookalike European mushroom called luridimormis/discolor is a highly prized edible commonly known as the Scarletina. So it comes down to your taste for adventure and your respect for received wisdom.


  • NH4OH (Ammonia): Cap surface yellow changes to dark slate and darker areas change to rusty brown. Cap flesh loses its blue staining.
  • KOH: Cap surface (and stem) turns blood-red to rusty brown. Cap flesh turns orange to orange brown.
  • FeSO4 (Iron Salts): Cap surface turns olive, but stem has no reaction. Cap flesh turns greenish olive.


National Audubon Society Field guide to Mushrooms, Gary Lincoff 0 Mushrooms of West Virginia and the Central Appalachians 0 North American Boletes 107 BENA 277

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