Major Groups > Polypores > Stemmed, Pale-Fleshed

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Key to Stemmed, Pale-Fleshed Polypores  


by Michael Kuo


The polypores keyed out below all have stems (lateral or central), and pale flesh (when fresh mushrooms are sliced). Genera included in the key: Abortiporus, Albatrellus, Amylosporus, Bondarzewia, Boletopsis, Grifola, Jahnoporus, Meripilus, Microporellus, Polyporoletus, and Polyporus, as well as a few species from other genera.



1.Growing above ground on the wood of trees, stumps, logs, branches, or sticks.
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1.Growing at the very bases of trees or stumps—or growing terrestrially, from buried roots or without clear association with a tree.
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2.Stem at maturity black or with a black base (caution: some species develop the black covering slowly, from the base upwards, and may lack the covering when young).
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2.Neither stem nor stem base black at maturity.
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3.Cap with scales.
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3.Cap without scales.
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4.Only rarely growing on wood; recorded only from California and the Southwest; scales raised, with sharp edges; stem with white hairs over the blackish portion; mushroom connected through the wood to a large underground mass of tissue (a "sclerotium").
Polyporus tuberaster

4.Always growing on wood; widely distributed but more common east of the Rocky Mountains; scales pressed down, with rounded edges; stem without white hairs; sclerotium absent.


5.Cap dark chestnut brown to reddish brown, often 10 or more cm across.

5.Cap dull yellow to pale tan, rarely wider than 6 cm.


6.Pores hexagonal or angular and radially elongated.
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6.Pores round or somewhat angular but not hexagonal, not radially arranged.
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7.Mature cap small (under 5 cm across).
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7.Mature cap larger than above.
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8.Cap brown to golden brown; cap margin hairy; stem usually central.

8.Cap orangish; cap margin not hairy; stem usually lateral, if present.


9.Cap with scales, yellowish to yellowish brown; growing in the Southwest and in California; mushroom connected through the wood to an large underground mass of tissue (a "sclerotium"); basidia without oil droplets.
Polyporus tuberaster

9.Cap smooth, white to creamy, often with a mottled appearance; growing in the tropics or along the Gulf Coast of the United States; sclerotium absent; basidia with oil droplets.


10.Cap dark brown or dark bronze.
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10.Cap white, buff, pale brown, or tan.
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11.Cap flat or shallowly depressed at maturity, not radially lined; pore surface not running down the stem; widely distributed.

11.Cap vase-shaped by maturity, radially lined; pore surface running down the stem; recorded from the Southeast.
Polyporus virgatus


12.Spores and pore surface amyloid; found from the Southwest to the Gulf Coast and the tropics.
Amylosporus campbellii

12.Spores inamyloid; variously distributed.
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13.Mature cap 6–30 cm across; found in northeastern North America.
Polyporus admirabilis

13.Mature cap smaller than above; variously distributed.
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14.Growing on the wood of conifers; flesh when dried becoming very hard; spores cylindric with a narrowed end, about 5–6 µm long.

14.Growing on the wood of hardwoods or conifers; flesh not becoming very hard on drying; spores varying.
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15.Found in the Southwest; cap creamy becoming brownish, mottled with darker spots.
Polyporus coronadensis

15.Found east of the Rocky Mountains; cap not mottled.
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16.With 1–3 pores per mm.
Polyporus craterellus

16.With 6–9 pores per mm.
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17.Cap with concentric zones; margin not hairy; widely distributed east of the Rocky Mountains.

17.Cap without concentric zones, margin hairy; recorded from the Gulf Coast and the tropics.
Polyporus tricholoma


18.Fresh cap blue or bluish.
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18.Fresh cap otherwise colored.
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19.Growing in the Pacific Northwest under Douglas-fir and other conifers; young pore surface whitish, eventually bluish or reddish; clamp connections present.
Albatrellus flettii

19.Growing in northeastern North America under eastern hemlock; young pore surface blue or gray, becoming grayish brown, eventually reddish; clamp connections absent.


20.Mushroom often covered nearly completely with whitish to pinkish pore surface; convoluted, lumpy, and amorphous—or sometimes more or less "normal" looking, with a whitish pore surface that runs down the stem and bruises reddish, and a tan to brown cap; typically growing under hardwoods but occasionally found under conifers; both spores and chlamydospores (roundish, thick-walled, asexual spores) present.

20.Not as above.
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21.Mushroom usually consisting of many fan-shaped, petal-shaped, or irregularly shaped caps sharing a stem or arising from a branched stem; occasionally occurring with a single cap.
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21.Mushroom usually consisting of one circular, kidney-shaped, or irregularly shaped cap on one stem (though individuals may grow in clusters with stems touching); occasionally with two or more caps ingrown or sharing a stem.
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22.Individual caps small (1–4 cm across) when fully grown.
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22.Individual caps larger than above when fully grown.
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23.Growing under Ponderosa pine, Douglas-fir, and western white pine in western North America; caps yellow to yellowish buff or yellowish brown; flesh brittle.
Albatrellus dispansus

23.Growing at the bases of hardwoods throughout North America; caps grayish brown; flesh not brittle.


24.Growing at the bases of living hardwoods in the southeastern United States and in the Caribbean; caps brownish to pinkish brown; stem lateral; pore surface pinkish buff.
Laetiporus persicinus

24.Not as above.
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25.Growing under hardwoods in the southwestern United States; caps yellowish to yellowish brown; mushroom connected to a large underground mass of tissue (a "sclerotium").
Polyporus tuberaster

25.Not as above.
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26.Pores averaging 1–2 per mm; cap surface not streaked; spores ornamented.
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26.Pores smaller than above (2–5 per mm); cap surface streaked; spores smooth.
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27.Found under conifers west of the Rocky Mountains; caps brown to purplish brown.
Bondarzewia occidentalis

27.Found under hardwoods east of the Rocky Mountains; caps whitish to tan or pale brown.


28.Pore surface and cap margin bruising dark brown to black; individual caps to 20 cm across, whitish to brownish; pore surface with 6–8 pores per mm; spores subglobose; clamp connections completely absent.

28.Pore surface and cap margin not bruising; individual caps to 8 cm across, lavender gray becoming brown; pore surface with 2–4 pores per mm; spores ellipsoid; clamp connections present in generative hyphae.


29.Cap usually round in outline, rather than kidney-shaped, lobed or irregular; stem usually more or less central; multi-capped or fused mushrooms rare.
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29.Cap occasionally round in outline but usually "roundish" to kidney-shaped, irregular or lobed; stem central or off-center; multi-capped or fused mushrooms more likely than above.
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30.Stem terminating in a long, underground root-like projection.
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30.Stem without a root-like projection.
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31.Above-ground portion of stem black and velvety.
Polyporus melanopus

31.Above-ground portion of stem whitish to reddish brown, not velvety.


32.Flesh in cap fairly thick, staining grayish, pinkish, or brownish when sliced; spores nodulose.
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32.Flesh in cap thin, not staining when sliced; spores not nodulose.
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33.Cap dull orange with gray areas; rare; found in the Pacific Northwest.
Boletopsis smithii

33.Cap grayish to brownish; variously distributed.
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34.Growing under pines; cap pale gray; mushroom usually short, with the cap about as wide as the stem is long.
Boletopsis grisea

34.Growing under spruces; cap dark gray; mushroom usually tall, with the stem longer than the cap width.


35.Growing in open fields, grassy areas, etc.; cap small (up to 3 cm across), grayish.
Polyporus cryptopus

35.Not as above.
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36.Growing under hardwoods.
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36.Growing under conifers.
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37.Cap brownish to yellowish, with olive to greenish shades; pore surface with greenish or olive shades.

37.Not as above.
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38.Pores large (1–2 per mm).
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38.Pores small (4–10 per mm).
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39.Cap whitish to pale yellowish or pale brownish, surface with small brownish scales; pore surface whitish; flesh white; arising from a large underground mass of tissue (a "sclerotium").
Polyporus tuberaster

39.Cap dark purplish gray, cinnamon buff, or tawny, surface hairy or velvety; pore surface grayish to purplish gray or olive; flesh pinkish; sclerotium absent.
Polyporoletus sublividus


40.Cap usually with concentric zones; pores very tiny (8–10 per mm); found in the southeastern United States.

40.Cap not strongly zoned; pores 4–6 per mm; variously distributed east of the Rocky Mountains.
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41.Cap yellow to yellow-brown; margin usually inrolled when young; stem yellowish or buff; spores elliptical.
Albatrellus peckianus

41.Cap white, becoming straw-colored with age; margin not typically inrolled; stem white; spores nearly round.
Abortiporus fractipes


42.Cap scaly, with yellowish green shades; pore surface whitish, bruising and aging yellowish green or greenish; stem with yellowish green shades.
Albatrellus ellisii

42.Not completely as above.
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43.Stem brown and minutely velvety; spores 12–17 µm long, spindle-shaped.
Jahnoporus hirtus

43.Stem paler than above, smooth; spores smaller, not spindle-shaped.
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44.Cap smooth when young (though possibly becoming cracked by maturity), creamy to whitish (but not orangish or pinkish buff); clamp connections absent.
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44.Young cap smooth or scaly, more highly colored (grayish to brownish or pinkish buff); clamp connections present.
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45.Cap cracking with age and showing pale yellowish flesh in the cracks; fresh stem and pore surface without reddish or orangish shades; spores inamyloid; widely distributed.

45.Cap rarely cracking with age, and then not showing flesh in the cracks; fresh stem and spore surface sometimes with reddish or orangish shades; spores amyloid; apparently southern (FL & AZ) in distribution.
Albatrellus subrubescens


46.Cap grayish becoming grayish brown, not cracking; stem reticulate, with greenish to brownish blotches; pore surface yellow; spores 7.5–10 x 5–7 µm; rare (apparently documented only once, in Washington).
Albatrellus skamanius

46.Not as above.
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47.Cap brown, with small scales; pores large (1–2 per mm or larger) and hexagonal or angular; stem bruising and discoloring brown to reddish brown.

47.Cap orangish to pinkish buff, smooth; pores small (3–5 per mm) and circular; stem not discoloring brownish.



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Cite this page as:

Kuo, M. (2007, April). Key to stemmed, pale-fleshed polypores. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/polypores_stemmed_pale.html

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