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.
En Français (French translation by Roland Labbé).
| 1. | Growing above ground on the wood of trees, stumps, logs, branches, or sticks. | 2 |
| 1. | Growing at the very bases of trees or stumps--or growing terrestrially, from buried roots or without clear association with a tree. | 17 |
| 2. | Stem black or with a black base. | 3 |
| 2. | Neither stem nor stem base black. | 6 |
| 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. | |
| 6. | Pores hexagonal or angular and radially elongated. | 7 |
| 6. | Pores round or somewhat angular but not hexagonal, not radially arranged. | 10 |
| 7. | Mature cap small (under 5 cm across). | 8 |
| 7. | Mature cap larger than above. | 9 |
| 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. | Polyporus tenuiculus |
| 10. | Cap dark brown or dark bronze. | 11 |
| 10. | Cap white, buff, pale brown, or tan. | 12 |
| 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. | 13 |
| 13. | Mature cap 6-30 cm across; found in northeastern North America. | Polyporus admirabilis |
| 13. | Mature cap smaller than above; variously distributed. | 14 |
| 14. | Found in the Southwest; cap creamy becoming brownish, mottled with darker spots. | Polyporus coronadensis |
| 14. | Found east of the Rocky Mountains; cap not mottled. | 15 |
| 15. | Pores very tiny (6-9 per mm). | 16 |
| 15. | Pores larger than above (1-3 per mm). | Polyporus craterellus |
| 16. | Cap with concentric zones; margin not hairy; widely distributed east of the Rocky Mountains. | |
| 16. | Cap without concentric zones, margin hairy; recorded from the Gulf Coast and the tropics. | |
| 17. | Fresh cap blue or bluish. | 18 |
| 17. | Fresh cap otherwise colored. | 19 |
| 18. | Growing in the Pacific Northwest under Douglas-Fir and other conifers; young pore surface whitish, eventually bluish or reddish; clamp connections present. | |
| 18. | Growing in northeastern North America under Eastern Hemlock; young pore surface blue or gray, becoming grayish brown, eventually reddish; clamp connections absent. | |
| 19. | 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. | 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. | 21 |
| 20. | 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. | 28 |
| 21. | Individual caps small (1-4 cm across) when fully grown. | 22 |
| 21. | Individual caps larger than above when fully grown. | 23 |
| 22. | Growing under Ponderosa Pine, Douglas-Fir, and western white pine in western North America; caps yellow to yellowish buff or yellowish brown; flesh brittle. | |
| 22. | Growing at the bases of hardwoods throughout North America; caps grayish brown; flesh not brittle. | |
| 23. | 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. | 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. | Pores averaging 1-2 per mm; cap surface not streaked; spores ornamented. | 26 |
| 25. | Pores smaller than above (2-5 per mm); cap surface streaked; spores smooth. | 27 |
| 26. | Found under conifers west of the Rocky Mountains; caps brown to purplish brown. | |
| 26. | Found under hardwoods east of the Rocky Mountains; caps whitish to tan or pale brown. | |
| 27. | Pore surface and cap margin bruising dark brown to black; individual caps to 20 cm across, whitish to brownish. | |
| 27. | Pore surface and cap margin not bruising; individual caps to 8 cm across, lavender gray becoming brown. | |
| 28. | Cap usually round in outline, rather than kidney-shaped, lobed or irregular; stem usually more or less central; multi-capped or fused mushrooms rare. | 29 |
| 28. | 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. | 34 |
| 29. | Stem terminating in a long, underground root-like projection. | 30 |
| 29. | Stem without a root-like projection. | 31 |
| 30. | Above-ground portion of stem black and velvety. | Polyporus melanopus |
| 30. | Above-ground portion of stem whitish to reddish brown, not velvety. | |
| 31. | Flesh in cap fairly thick, staining grayish, pinkish, or brownish when sliced; spores angular. | 32 |
| 31. | Flesh in cap thin, not staining when sliced; spores not angular. | 33 |
| 32. | Cap dull orange with gray areas; recorded once in the Pacific Northwest. | Boletopsus smithii |
| 32. | Cap grayish to brownish; widely distributed. | |
| 33. | Growing in open fields, grassy areas, etc.; cap small (up to 3 cm across), grayish. | Polyporus cryptopus |
| 34. | Growing under hardwoods. | 35 |
| 34. | Growing under conifers. | 40 |
| 35. | Cap brownish to yellowish, with olive to greenish shades; pore surface with greenish or olive shades. | |
| 36. | Pores large (1-2 per mm). | 37 |
| 36. | Pores small (4-10 per mm). | 38 |
| 37. | 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 |
| 37. | 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 |
| 38. | Cap usually with concentric zones; pores very tiny (8-10 per mm); found in the southeastern United States. | |
| 38. | Cap not strongly zoned; pores 4-6 per mm; variously distributed east of the Rocky Mountains. | 39 |
| 39. | Cap yellow to yellow-brown; margin usually inrolled when young; stem yellowish or buff; spores elliptical. | Albatrellus peckianus |
| 39. | Cap white, becoming straw-colored with age; margin not typically inrolled; stem white; spores nearly round. | Abortiporus fractipes |
| 40. | Cap scaly, with yellowish green shades; pore surface whitish, bruising and aging yellowish green or greenish; stem with yellowish green shades. | Albatrellus ellisii |
| 41. | Stem brown and minutely velvety; spores 12-17 µ long, spindle-shaped. | |
| 41. | Stem paler than above, smooth; spores smaller, not spindle-shaped. | 42 |
| 42. | Cap smooth when young (though possibly becoming cracked by maturity), creamy to whitish (but not orangish or pinkish buff); clamp connections absent. | 43 |
| 42. | Young cap smooth or scaly, more highly colored (grayish to brownish or pinkish buff); clamp connections present. | 44 |
| 43. | 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. | |
| 43. | 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. | |
| 44. | Cap grayish becoming grayish brown, not cracking; stem reticulate, with greenish to brownish blotches; pore surface yellow; spores 7.5-10 x 5-7 µ; rare (apparently documented only once, in Washington). | Albatrellus skamanius |
| 45. | 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. | |
| 45. | Cap orangish to pinkish buff, smooth; pores small (3-5 per mm) and circular; stem not discoloring brownish. | |
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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