Neoboletus discolor [auct. amer.] (“Scarletina”)

Yellow/red cap bruises black. Yellow baby pores age to bright red & blue instantly. Yellow flesh blues instantly. Hugely variable yellow stem bruises blue-black.

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Genus: Neoboletus

  • Genus 2: Boletus
  • Genus 3: Sutorius

Species: discolor (in the sense of American authors, since the species name will change in the next few years. See the Science Notes)

  • Species 2: subluridellus (probably where this will end up)
  • Species 3: erythropus ssp. discolor
  • Species 4: luridiformus ssp. discolor
  • Species 5: chamaeleon (a provisional name used by Dr. Igor Safonov on Mushroom Observer)

Common Name: “Scarletina” or “Red Mouth Bolete”

Tells: Yellow/red cap bruises black. Yellow baby pores age to bright red & blue instantly. Yellow flesh blues instantly. Hugely variable yellow stem bruises blue-black.

Other Information: Pale yellow flesh quickly blues. Cap color starts yellow/orange but is immensely variable and subject to appearing darker because it bruises so easily. 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 Neoboletus subvelutipes. Neoboletus luridiformis has a darker cap and darker yellow flesh than discolor, but both of these species have enormous flexibility in how they appear, so expect to have cases where they can be confused for each other. The reported chemical tests are distinctly different for Ammonia and KOH, but experience has shown this to be unreliable.

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 We can be pretty sure they are not the European queletii and unpublished amateur DNA work shows that the oak-loving ones do indeed follow the same pattern – massive morphological flexibility with the same DNA – but what is the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: Your author finds them delicious, as did Gary Lincoff, and has eaten them regularly for the past several years. With that said, Scarletinas remain on the “Iffy” list rather than “Choice” because the traditional instruction in America was so clear: “Avoid the red-pored blue-stainers like this one unless you want to get sick.” That myth has now been destroyed, but we do not have the many decades of practical experience required to be 100% sure about things like individual sensitivities and whether my European sources are right about the need to cook them extra thoroughly. So I guess the bottom line would be this: “Choice, with cautions and maybe reservations.”


  • 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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