Major Groups > Boletes > Red-Pored Boletes


Key to 47 Red-Pored Boletes in North America  

by Michael Kuo

1.Neither pore surface nor flesh discoloring blue when bruised or sliced.

1.Either pore surface, flesh, or both discoloring a shade of blue when bruised or sliced.

2.Cap rosy red, overlaid with red fibrils and scales (reminiscent of Suillus pictus); possibly known only from the 1938 type collection made in Great Smoky Mountains National Park.
Boletus rubropictus

2.Cap not as above; variously distributed and collected.

3.Stem reticulate, at least over the top portion.

3.Stem not reticulate.

4.Fresh cap wine red; apparently known only from the 1965 type collection, made under hardwoods in Oakland County, Michigan.
Boletus holoroseus

4.Fresh cap a shade of yellow, orange, or brown.

5.Fresh cap orangish brown; apparently known only from the 1965 type collection, made under hardwoods in Washtenaw County, Michigan.
Boletus eberwhitei

5.Fresh cap golden to yellow or orange-yellow.

6.Basal mycelium usually white; flesh white; fresh cap and stem dusted with a yellow powder that stains surfaces (including fingers) yellow; spores 8–12 µm long.
Pulveroboletus auriflammeus

6.Basal mycelium golden yellow; flesh yellow to yellowish; cap and stem surfaces not as above; spores 14–16 (–22) µm long.
Boletus magnisporus

7.Fresh cap dark red; flesh in cap whitish, staining purplish red when sliced; stem with raised longitudinal ribs near the apex; flesh in stem dark red; known from north-central and southeastern Michigan.
Boletus roseobadius

7.Fresh cap variously colored; cap flesh white to yellow, not staining purplish red; stem not as above; variously distributed.

8.Basal mycelium white; cap red, fading to yellowish; cap usually about 4 cm across when mature.
Chalciporus rubinellus

8.Basal mycelium pale to bright yellow or golden; cap color varying; cap often larger than 4 cm across when mature.

9.Flesh white; fresh cap bright golden yellow; found under hardwoods in northeastern North America.
Boletus magnisporus

9.Flesh yellowish to yellow; fresh cap variously colored; usually found under conifers or in mixed woods; variously distributed.

10.Taste bitter; common and widely distributed.

10.Taste mild or slightly acidic, but not bitter; uncommon and probably distributed only east of the Rocky Mountains.

11.Cap and stem dusted with yellow powder when fresh and young; growing from (or near) deadwood or roots of pines; young pore surface running down the stem.

11.Cap and stem not dusted with yellow powder; not associated with wood; young pore surface not running down the stem.

12.Cap yellowish with pinkish hues; flesh yellow to yellowish; young pore surface fairly bright red; spores olive to olive yellow in KOH.
Chalciporus pseudorubinellus

12.Cap orangish, becoming dull reddish brown; flesh white or faintly yellowish; young pore surface dull red; spores hyaline to yellowish in KOH.
Chalciporus rubritubifer

13.Stem reticulate.

13.Stem not reticulate (or, rarely, very slightly reticulate at extreme apex).

14.Fresh cap whitish to pinkish or pale gray (sometimes becoming very pale brownish with age).

14.Cap more highly colored (red, brown, tan, orange, etc.).

15.Associated with oaks in coastal California.
Boletus eastwoodiae
= "B. satanas" sensu auct. N. Am.

15.Associated with various oaks and with beech in eastern North America, especially in the southern Appalachians.
Boletus firmus
= B. piedmontensis
= B. satanas
var. americanus

16.Found in western North America.

16.Found from the Great Plains eastward.

17.Stem apex pinkish to reddish or reddish brown with red reticulation; pore surface red from the beginning; associated with various conifers.
Boletus pulcherrimus

17.Stem apex yellowish to brownish with red reticulation; pore surface bright yellow at first, becoming red; associated with red fir.
Boletus haematinus

18.Young cap dark pink with a whitish bloom, maturing to brownish pink, red, or purplish red, often with brown or olive shades mixed in; odor and taste strong, sickly sweet; ammonia flashing bluish on cap surface.
Rubroboletus rhodosanguineus

18.Cap variously colored but not pink when young; odor and taste not distinctive; ammonia flashing blue on cap surface or not (untested for a few species).

19.Fresh cap a shade of red.

19.Fresh cap a shade of brown or yellow.

20.Stem conspicuously, deeply, coarsely reticulate (illustration); fresh cap bright red and sticky (pileipellis an ixocutis).

20.Reticulation not deep and coarse; fresh cap variously colored but, with one exception, not sticky under normal conditions (pileipellis not gelatinized).

21.Sliced flesh not bluing; associated with hardwoods; known from the southeastern United States.
Boletus carminiporus

21.Sliced flesh bluing; associated with hardwoods or conifers; distribution varying.

22.Associated with conifers; merely finely reticulate on the upper stem.
Boletus flammans

22.Associated with hardwoods; reticulation more prominent than above.

23.Pore surface dark red, not beaded with droplets when young; widely distributed east of the Great Plains; young cap surface matted with grayish material that later can be seen on the cap margin.

23.Pore surface reddish orange, when young with beads of liquid; distributed from the southern Appalachians to Texas and Florida; cap surface not matted with gray material when young, but cap margin often yellowish or whitish (innate color).

24.Young pore surface dark brown.
Boletus fagicola

24.Young pore surface red to orange.

25.Cap reddish brown; southeastern in distribution; cap margin often yellowish or whitish.

25.Cap a shade of brown or yellow but not reddish brown; distribution varying; cap margin not usually differently colored.

26.Cap golden yellow; basal mycelium golden yellow (even when dried); spores 14-16 (-22) µ long.
Boletus magnisporus

26.Cap a shade of brown; basal mycelium red, purplish, brown, or olive; spores usually shorter than above.

27.Spores 12–17 µm long; hymenial cystidia hyaline to yellowish in Melzer's reagent; stem with a red to brown or dark wine colored base; widely used European name for what is probably a group of eastern North American species.

27.Spores 9–12 µm long; cystidia dark brown in Melzer's; stem with a dark wine colored base; known from two locations in lower Michigan.
Boletus vinaceobasis

28.Found from the Rocky Mountains westward.

28.Found from the Great Plains eastward.

29.Fresh cap bright yellow; spores under 7 µm long.
Boletus orovillus

29.Cap a shade of pink, red, tan, or brown; spores longer than 7 µm.

30.Cap dull red to tan or dull pinkish buff; pore surface dull reddish to reddish brown or dull orangish; basal mycelium bright yellow and prominent; KOH black on cap surface.

30.Cap variously colored; pore surface brighter red or orange than above; basal mycelium, if yellow, not prominent; KOH not black on cap (but reaction for one species not recorded).

31.Cap finely velvety, becoming conspicuously cracked (like the cap of Xerocomellus chrysenteron); spores 15–21 (–27) µm long.
Boletus mendocinensis

31.Cap bald or nearly so, not usually becoming conspicuously cracked; spores 12–16 µm long.

32.Cap pink to red; associated with Pacific madrone or manzanita.
Boletus amygdalinus

32.Cap brown to reddish brown; associated with coast live oak or tanoak.
Boletus erythropus
sensu CA authors

33.Fresh cap whitish to pinkish or pale gray; occasional in the Appalachians, but more rare elsewhere.
Boletus firmus
= B. piedmontensis
= B. satanas
var. americanus

33.Fresh cap more highly colored; variously distributed.

34.Young pore surface brown, very dark reddish brown, deep maroon, or yellowish brown; mature pore surface brownish orange.

34.Young pore surface red, orange, or yellow; mature pore surface red to orange.

35.Stem base reddish; young pore surface yellowish brown; spores 10–13 x 3.5–4.5 µm; odor of dried specimens strong and disagreeable.
Boletus subgraveolens

35.Stem base not reddish; young pore surface very dark reddish brown to deep maroon; spore dimensions varying; odor of dried specimens not strong and disagreeable.

36.Cap tan to medium yellowish brown or medium grayish brown, often with a yellow marginal zone; spores 9–12 x 3–3.5 µm.

36.Cap darker than above (dark brown to dark gray-brown); marginal zone, if present when young, pale brown; spores 10–5 x 4–6 µm.
Boletus vermiculosus

37.Cap golden yellow to bright yellow.

37.Cap not yellow.

38.Growing from (or near) deadwood or roots, under pines; cap golden yellow and powdery; spores 6–9 x 2.5–4 µm.

38.Not associated with deadwood or roots; found under hardwoods; spores 10–22 x 4.5–9 µm.
Boletus magnisporus

39.Cap dull red to tan or dull pinkish buff; fresh pore surface dull reddish to reddish brown or dull orangish; pores often elongated and angular near the stem; basal mycelium bright yellow and prominent; KOH black on cap surface.

39.Not with the above combination of features.

40.Cap a shade of red.

40.Cap not red.

41.Cap sticky when fresh (and, when dried out, often shiny and/or covered with adhering leaves and debris), bright red (like the cap of Butyriboletus frostii), and bald; stem yellow, distinctively adorned with tiny red fibers and scales.

41.Cap dry throughout development, rarely bright red, bald or finely velvety; stem varying.

42.Sliced flesh bluing only slightly, in the stem apex; tube layer proportionally shallow (about 5 mm deep for a 10 cm cap).
Boletus bicolor var. borealis

42.Sliced flesh bluing more convincingly; tube layer not proportionally shallow.

43.Flesh in cap white to whitish; known from the Lower Peninsula of Michigan.
Boletus roseobadius

43.Flesh in cap pale to deep yellow; variously distributed.

44.Flesh strongly to weakly malodorous (reminiscent of spoiled onions or bad meat); known distribution from the Gulf Coast to Tennessee and Virginia.
Boletus subluridus
(? = B. underwoodii)

44.Flesh not malodorous; variously distributed.

45.Known only from the Gulf Coast; spores 12–19 x 5–8 µm long; caulocystidia not elongated.
Boletus fairchildianus

45.Variously distributed, but not recorded from the Gulf Coast; spores 9–17 x 4–6.5 µm; some caulocystidia elongated (30–200 µm long).

46.Some pileipellis and subcuticular elements red in Melzer's reagent (illustration); cap red with a thin layer of brownish fuzz, maturing to red, bruising dark purple; young cap with a resinous feel.

46.Pileipellis and subcuticular elements brownish to rusty in Melzer's; cap brick red, with or without a yellowish bloom, maturing to cinnamon, bruising dark blue to black; young cap not resinous to the touch.
Boletus rufocinnamomeus

47.Brown cap colors resulting from a brownish tomentum (velvety fuzz) that can be rubbed away to reveal a red cap surface; caulocystidia elongated; some pileipellis and subcuticular elements red in Melzer's reagent (illustration).

47.Brown cap colors innate; caulocystidia not elongated; pileipellis and subcuticular elements yellowish to brownish to faintly pink in Melzer's.

48.Stem densely covered with purple-brown floccules and fibrils; cap conspicuously velvety; known from Florida.
Boletus austrinus

48.Stem not covered with purple-brown material; cap velvety or bald; variously distributed.

49.Basal mycelium white; spores 8.5–11.5 µm long; known from the southeastern United States.
Boletus hypocarycinus

49.Basal mycelium yellow to red, purplish red, olive, or brown; spores 10–18 µm long; variously distributed.

50.Mushroom identifier willing to accept that the remaining species are insufficiently defined, poorly documented, interpreted differently by various authors, and in desperate need of a thorough, contemporary revision.
Boletus subvelutipes
(species group)

50.Mushroom identifier clings to species concepts that are over 40 years old and did not work very well even when they were contemporary.

51.Stem base with prominent red hairs or scurf; spores 14–18 x 5–6.5 µm; cap yellow as dried; North American species named by Peck in 1889.
Boletus subvelutipes
(interpreted strictly)

51.Stem base without red hairs; spores variously sized; cap not yellow as dried; European species names used by North American authors.

52.Flesh in base of stem purplish red; spores broadly fusiform to nearly ellipsoid (10–14 x 5.5–7 µm); cap dark brown at first, developing orange to yellow shades with age; reported from Vermont by Snell & Dick (1970).
Boletus queletii

52.Flesh in stem base yellow or dull red but not deep purplish red; spores fusiform to subfusiform (13–17 x 4–6 µm); cap variously colored; frequently reported by many North American authors using differing concepts.

53.Cap yellowish to yellowish brown; floccules on stem very fine. According to Both (1993) this is probably the mushroom described by Smith & Thiers (1971) as "Boletus erythropus."
Boletus luridiformis var. discolor

53.Cap brown to olive brown or reddish brown; floccules on stem larger than above.
Boletus luridiformis
(= Boletus erythropus)

Uncertain species not included in the key:

(References used for this page can be found in the reference list for boletes.)

This site contains no information about the edibility or toxicity of mushrooms.

Cite this page as:

Kuo, M. (2020, July). Key to 47 red-pored boletes in North America. Retrieved from the MushroomExpert.Com Web site: