Major Groups > Boletes > Tylopilus

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The Genus Tylopilus  

[ Basidiomycota > Boletales > Boletaceae . . . ]

by Michael Kuo

A handful of Tylopilus species grow in western North America, but the majority are eastern in distribution. Most are fairly easily distinguished from other boletes by their pinkish pore surfaces—though young specimens in the button stage often have a whitish pore surface, causing confusion with other boletes, and a handful of species have brown pore surfaces. There is no partial veil, and the spore print is usually pinkish brown to reddish brown, or in a few cases chocolate brown. Like almost all boletes, species of Tylopilus are mycorrhizal, involved in symbiotic relationships with trees.

Identification of species in Tylopilus can be frustrating. While the characters used for identification of the species (as they are currently defined) are primarily macroscopic and fairly easy to assess, there appear to be more species in the woods than there are in the books—and, in the case of Tylopilus, it really is the case that you will need specimens from all stages of development (from buttons to mature mushrooms) in hand if you want to get very far with your identification efforts.

Taste is an important element in Tylopilus identification; some are extremely bitter, while others are mild. Additionally, the stem of a Tylopilus specimen often winds up bearing much of the identification burden: pay special attention to its colors, bruising and/or discoloring, and reticulation (which may be absent, faintly present near the apex, or prominent). Cap color is an extremely variable feature, and many species of Tylopilus go through a bewildering series of color stages during the course of development. The color of the young cap, however, is often distinctive even when the mature cap fades to wishy-washy tan, as it almost always does. Microscopic examination is usually not required to identify a species of Tylopilus, but in a few cases measuring spores can make things a lot easier.

And now the inevitable DNA-based rejoinder. "Tylopilus" as it exists in your field guide is pretty much a fantasy. Again and again, molecular studies have supported the idea that a genus based on the concepts I outlined above is astoundingly "polyphyletic," which is Molecular Biologese for "they don't all fit in there." While a core group of Tylopilus species centered around Tylopilus felleus (the "type species" of the genus) is clearly defined and will one day have to represent the genus, other putative species of Tylopilus are not even closely related to the the felleus group. It will be a while before the dust settles. But in the meantime (and perhaps even afterward) the characters we are used to using for identification of the mushrooms can still serve that purpose.

 		 

Tylopilus felleus

Tylopilus alboater

Tylopilus rubrobrunneus

Tylopilus sordidus



Key to 34 Tylopilus and Tylopilus-like Species in North America  


1.Taste bitter.
2

1.Taste not bitter.
15


2.Young cap bright orange to orange-red; pore surface bruising brown.

2.Young cap not orange; pore surface bruising brown or not.
3


3.Young pore surface brown; stem with Leccinum-like scabers; young cap velvety, purplish brown.
Sutorius eximius

3.Young pore surface not brown; stem without scabers; young cap velvety or not, variously colored.
4


4.Young stem (ignore the cap) with purple to lilac shades.
5

4.Young stem without purple to lilac shades.
6


5.Spores 7–10 µm long; cap bruising rusty purple to dark purple; stem bruising yellow to yellow-brown, lacking olive discolorations.
Tylopilus violatinctus

5.Spores 10–13 µm long; cap not bruising; stem sometimes bruising olive to olive brown.


6.Young cap white to whitish.
7

6.Young cap more highly colored.
10


7.Stem coarsely and dramatically pocketed-reticulate; found in pine-oak woods from New Jersey to Florida and Texas.

7.Stem smooth or, if reticulate, not coarsely so; variously distributed.
8


8.Distribution northeastern and Midwestern, extending into the southern Appalachians; stem bruising and staining brown; cap "skin" thin and papery, often peeling and fragmenting with age.
Tylopilus intermedius

8.Distribution southeastern, extending into the southern Appalachians; stem not bruising brown; cap skin not as above.
9


9.Usually associated with pines; spores 10–14 µm long.

9.Usually associated with hardwoods; spores 7–10 µm long.
Tylopilus peralbidus


add 1 below



10.Stem reticulate.
11

10.Stem not reticulate, or only very finely so at apex.
12


11.Associated with conifers; reticulation coarse; cap 5–13 cm across.

11.Associated with oaks (but often in pine-oak forests); reticulation fine; cap 2–6 cm across.
Tylopilus minor


12.Young cap purple to purple-brown (but older caps may lose all traces of purple).
13

12.Cap never purple.
14


13.Widely distributed east of the Great Plains; stem developing olive to olive brown stains and discolorations; iron salts negative to pinkish on flesh; spores 9–14 µm long.

13.Distributed from Florida to Mexico; stem not developing olive stains; iron salts greenish on flesh; spores 7.5–11 µm long.
Tylopilus williamsii


14.Cap, stem, and pore surface staining brown when bruised; usually found in pine-oak woods; flesh white with distinctive semi-transparent marbling.
Tylopilus rhodoconius

14.Pore surface staining brown but not the cap, nor the stem; usually found in hardwoods forests; flesh whitish to yellowish, without marbling.
Tylopilus appalachiensis


15.Found from the Rocky Mountains westward.
16

15.Found east of the Rocky Mountains.
19


16.Young pore surface brown; associated with conifers (Sitka spruce, pines); stem medium to dark brown.
Porphyrellus porphyrosporus

16.Young pore surface not brown; associated with hardwoods or conifers; stem whitish to tan.
17


17.Associated with pines; mushrooms fairly small (usually under 10 cm), often growing underground and emerging at maturity; stem stout, often not completely central, not reticulate.
Tylopilus humilis

17.Associated with hardwoods; mushrooms larger and not developing underground; stem not normally stout, usually central, reticulate or not.
18


18.Stem reticulate; associated primarily with coast live oak.
Tylopilus "indecisus"
West-Coast misapplication
(≠ T. indecisus)

18.Stem not reticulate; associated with black oak.
Tylopilus ammiratii
in Thiers, 1975


19.Pore surface, and often the flesh, bruising or staining blue.
20

19.Blue staining absent.
21


20.Under hardwoods; young pore surface whitish; odor not distinctive; spores 4–6 µm wide.

20.Under conifers; young pore surface brown to brownish; odor foul or reminiscent of chlorine (crush the stem base); spores 6–7.5 µm wide.
Porphyrellus porphyrosporus


21.Stem with pink, red, brown, or blackish, Leccinum-like scabers.
22

21.Stem without scabers.
23


22.Scabers dark; cap purplish brown; young pore surface brown.
Sutorius eximius

22.Scabers pink to red; cap pink to pinkish tan; young pore surface whitish.


23.Stem prominently reticulate over the upper one-third or more.
24

23.Stem not reticulate, or merely finely so at apex.
26


24.Cap and stem dark gray; flesh gray.
Tylopilus griseocarneus

24.Cap and stem not gray; flesh not gray.
25


25.Associated primarily with southern oaks along the Gulf Coast (but also reported from North Carolina and West Virginia); pore surface whitish becoming brownish to brown, not rapidly bruising; sliced flesh turning purplish.
Tylopilus tabacinus

25.Associated with oaks throughout the Midwest and eastern North America; pore surface white becoming pinkish brown, bruising brown promptly; sliced flesh turning brownish in places.


26.Fresh cap bright orange; distributed south of a line between Boston and Dallas.

26.Fresh cap not bright orange; variously distributed.
27


27.Young cap shaggy and scaly, broadly conic, golden to yellow-brown, with tissue hanging from the margin; found under pines in the southeastern United States.
Veloporphyrellus conicus

27.Cap variously colored but never scaly, shaggy, conic, or with tissue hanging from the margin; variously distributed.
28


28.Sliced flesh eventually turning gray to black, with or without a reddish stage first, over the course of 20 minutes; cap usually very dark (black, dark gray, very dark brown); pore surface bruising black to blackish brown.
29

28.Sliced flesh not turning black to gray after 20 minutes; cap color varying but not usually as above; pore surface, if bruising, bruising pink or pale to medium brown.
32


29.Young pore surface gray, maturing to brown; stem very dark brown; spores 11–20 µm long.
Tylopilus nebulosus

29.Young pore surface white, maturing to pink or brown; stem black or dark brown; spores under 12 µm long.
30


30.Flesh when sliced staining blackish to black without a red stage; associated with eastern hemlock.
Tylopilus atratus

30.Flesh staining first red, then black when sliced; associated with oaks.
31


31.Cap black and, when fresh and young, velvety; widely distributed east of the Great Plains.

31.Cap brown and bald; known from the Appalachian Mountains.
Tylopilus atronicotianus


32.Cap, stem, and pore surface bruising strongly brown; stem with a distinctive white apex; flesh when sliced whitish, marbled with colorless areas; known from Florida to Cape Cod.
Tylopilus rhodoconius

32.Cap and stem not notably bruising; pore surface bruising or not; stem apex white or not; flesh not marbled; variously distributed.
33


33.Associated with eastern hemlock; stem usually proportionally long and slender; spores minutely pitted at maturity.

33.Associated with oaks and other hardwoods; stem not normally long and slender; spores not pitted.
34


34.Stem whitish at first, sometimes maturing to brownish but never highly pigmented; spores 10–15 µm long.

34.Stem brown to reddish brown or purplish brown, pigmented from the beginning; spores variously sized.
35


35.Young cap brown to reddish brown; young specimens often notably stocky and firm-fleshed; spores 10–14 µm long.

35.Young cap maroon; young specimens not usually stocky or firm-fleshed; spores 8–11 µm long.






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. (2016, September). The genus Tylopilus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/tylopilus.html



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