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The Genus Tricholoma  

[ Basidiomycetes > Agaricales > Tricholomataceae . . . ]


by Michael Kuo

Tricholoma is a fairly large genus of mycorrhizal gilled mushrooms with white spore prints, fleshy stems, and gills that are attached to the stem, often by means of a slight "notch." Though species of Tricholoma can be found across our continent from spring to fall (and nearly year-round in warm climates), the mushrooms tend to like cooler conditions and are most abundant in montane and northern forests, particularly in the fall. Some species are distinctive--especially those with rings (formerly placed in the genus Armillaria) and those with a strong, foul odor reminiscent of coal tar. Many other Tricholoma species, however, are grayish or brownish, and frustratingly similar.

Though microscopic features enable mycologists to separate a few Tricholoma species, most of the 100 or so species in North America are defined on the basis of physical features that do not require a microscope to determine. Unfortunately, these physical features are often variable, hard to determine with exactitude, and debated by mycologists. The texture of the cap, colors, bruising and discoloring reactions, odors, and tastes define most of the species.

 

Tricholoma sp.

Tricholoma magnivelare

Tricholoma saponaceum


Microscopic features include the presence or absence of cystidia and clamp connections, and spore size. Mycologists have bravely erected "subgenera" and "sections" to organize the mushrooms on the basis of some of these microscopic features, but these lines in the sand tend to get washed away by the tide of subtle differences in macrofeatures that define most Tricholoma species.

Technical treatments of Tricholoma in North America (most of which are listed below) are hard to come by, and consist of the doctoral dissertations and masters theses of Tricholoma experts treating limited areas of the continent and publications in mycological journals that treat small sections of the genus or describe a few new species. DNA studies have not yet focused on Tricholoma, to my knowledge, but a few Tricholoma species included in studies with wider focus have "held up," and the genus seems to be genetically distinguishable (once amended to include some of the ringed species formerly placed in Armillaria and exclude species now placed in Macrocybe).

I suspect that ecology will eventually turn out to be very important in Tricholoma studies; distribution, precise determination of mycorrhizal hosts, and analysis of forest types may eventually help us identify and define species more accurately. The "best" species in the key below are not only morphologically distinct but ecologically distinct, as well.




Key to Tricholoma in North America

Bypass Links:

Ring present
No ring, hardwoods
No ring, conifers


1.Stem with a ring or prominent, flaring sheath.
2

1.Ring or flaring sheath absent, though a cortina or ring zone may be present.
13


 [Ring present . . . ]
 

2.Mycorrhizal with hardwoods or blueberry bushes.
3

2.Mycorrhizal with conifers.
7


3.Spores amyloid; western species.

3.Spores inamyloid; western and eastern species.
4


4.Mycorrhizal with willows in northern North America from coast to coast; cap grayish; taste mealy; gills developing greenish yellow stains.
Tricholoma cingulatum
at Fungi of Poland

4.Not completely as above.
5


5.Probably mycorrhizal with blueberry bushes (or oaks?); flesh discoloring bluish to grayish when sliced; gills bluish gray in age; taste bitter or disagreeable; cap reddish to cinnamon brown; iron salts gray in stem base.
Tricholoma caligatum
var. glaucescens

5.Not completely as above.
6


6.Taste bitter; cap with dark brown fibers and scales; mycorrhizal with oaks.

6.Taste mild; cap with pale brown fibers and scales; hardwood mycorrhizal partners uncertain.


7.Cap orangish to orangish brown; odor and taste mealy.
8

7.Cap otherwise colored (brown, cinnamon brown, grayish, whitish, etc.); odor and taste mild, bitter, or mealy.
9


8.Lacking a true ring or a flaring sheath; "sheath" merely composed of dark scales on the stem surface that terminate in a line near the apex.

8.With a true ring.


9.Taste very bitter; cap 4.5-7 cm across, with dark brown fibers and scales over a whitish background; found in western North America; spores 5-7 x 4-6 µ.
Tricholoma caligatum
sensu Shanks
= T. caligatum var. occidentalis Smith

9.Not completely as above.
10


10.Spores amyloid; western species.

10.Spores inamyloid; western and eastern species.
11


11.Stem slimy, staining brownish with age; cap dry (possibly slimy when young), whitish or tinged with yellow, with pressed-down fibers; odor strongly pungent and alkaline; taste mild; mycorrhizal with Eastern Hemlock in eastern North America (possibly also occurring in the Rocky Mountains under unspecified conifers).
Tricholoma viscidipes

11.Not completely as above.
12


12.Odor and taste strongly mealy; ring inconspicuous and fragile; cap whitish at first but soon grayish to brownish; found in western North America; spores 8-12 x 5-6 µ; clamp connections present.
Tricholoma vernicatum
at MykoWeb
= Armillaria olida

12.Odor spicy (reminiscent of cinnamon), taste mild; ring thick and persistent; cap whitish with pale brown fibers and scales; widely distributed in western and northern North America; spores 6-8 x 4-6 µ; clamp connections absent.


13.Mycorrhizal with hardwoods (if your collection was made in "mixed woods," try conifers first).
14

13.Mycorrhizal with conifers.
57


 [No ring, hardwoods . . . ]
 

14.Cap white or whitish overall when mature.
15

14.Cap more highly colored when mature.
22


15.Taste mealy.
16

15.Taste not mealy (mild, bitter, acrid, or disagreeable).
19


16.Mycorrhizal with tanoak and madrone in California, fruiting in winter; cap whitish with grayish fibers, at least over the center; gills white or flushed with pink.

16.Not completely as above.
17


17.Cap with prominent, radiating, tan to brownish fibers over a whitish to buff ground color.

17.Cap without prominent tan to brownish fibers (fibers, if present, whitish and/or minute).
18


18.Cap pure white or with tan shades, especially over the center; cap and stem sometimes discoloring bluish to greenish; common in the Great Lakes states and eastern North America.

18.Cap without tan shades; cap and stem not discoloring, or discoloring reddish, yellowish, or bluish; European species whose presence in North America is debatable.
Tricholoma columbetta &
Tricholoma resplendens

see T. subresplendens


19.Cap with densely interwoven fibers, usually with grayish or tan shades mixed with white; gill edges bruising and discoloring grayish to blackish; odor not distinctive; taste mild or bitter.
Tricholoma serratifolium

19.Not completely as above.
20


20.Cap, stem and gills discoloring yellowish; flesh yellowing when sliced; odor strong and unpleasant (reminiscent of coal tar); taste disagreeable; found east of the Rocky Mountains.
Tricholoma suphurescens

20.Not completely as above.
21


21.Taste very bitter; odor fragrant, mealy, or foul; gills separable as a layer; cap margin inrolled and ridged; recorded in eastern North America; spores spiny and amyloid; basal mycelium copious and spreading through substrate. (Not mycorrhizal.)
Leucopaxillus laterarius
= Tricholoma acerbum

21.Taste bitter at first, then peppery-hot; odor strong and unpleasant; gills tightly affixed; cap margin not ridged; European species whose presence in North America is debatable; spores not spiny or amyloid; basal mycelium not copious.
Tricholoma album


22.Cap yellow or yellowish--or discoloring yellow, or yellow to yellowish underneath darker fibers or scales.
23

22.Yellow shades absent from cap.
29


23.Odor strong and unpleasant, reminiscent of coal tar.
24

23.Odor mild, soapy, fragrant, or mealy.
26


24.Cap whitish to buff when young, often with a yellowish or tan center; cap and stem bruising and discoloring yellow; flesh yellowing when sliced.
Tricholoma sulphurescens

24.Cap yellow or yellowish when young; cap and stem with yellow shades but not bruising yellow; flesh not yellowing when sliced.
25


25.Cap and gills yellow or yellowish when young, but fading to buff or whitish by maturity.

25.Cap and gills yellow or yellowish when young, not fading to buff or whitish.
Tricholoma sulphureum
at Fungi of Poland


26.Cap with a yellow to yellowish ground color, overlaid with substantially darker pressed-down fibers; taste mild, acrid, or mealy.
27

26.Cap yellow to yellowish overall; pressed-down fibers if present yellowish or very pale grayish; taste mealy.
28


27.Cap ground color more or less olive, with yellow shades near the margin; odor mild; taste mild becoming acrid; gills sometimes discoloring brownish on their edges; cap slimy when fresh and young.
Tricholoma palustre

27.Cap ground color more yellow than above, with olive shades sometimes mixed in; odor mealy; taste mealy; gills not discoloring; cap dry.


28.Cystidia present on gill edges; cap color smoky yellow, with or without a grayish center.
Tricholoma fumosoluteum

28.Cystidia absent; cap color yellow with a brownish gray center.
Tricholoma subluteum


29.Taste mild, soapy, bitter, or acrid--but not mealy.
30

29.Taste mealy.
40


30.Mycorrhizal with Manzanita in California, fruiting in winter; cap initially buff, becoming pale orangish and eventually brownish, at least over the center; gills white at first, becoming flushed with pink or orange, eventually yellowish; stem whitish with yellowish fibers; all parts frequently discoloring reddish with age.
Tricholoma manzanitae

30.Not completely as above.
31


31.Cap ground color more or less olive, with dark gray to blackish pressed-down fibers overlaid; gills yellowish green, sometimes discoloring brownish on their edges; stem yellowish green, often with a pinkish base; known from oak-hickory and beech-maple woods in the Great Lakes states, eastern North America, and Texas.
Tricholoma palustre

31.Not completely as above.
32


32.Stem white with the base flushed greenish or bluish, with yellow basal mycelium present; cap grayish to brownish with blackish fibers or scales; gills white at first, becoming pinkish or reddish, sometimes with blackish edges; reported from the Pacific Northwest and California.
Tricholoma orirubens

32.Not completely as above.
33


33.Cap orange-brown to reddish brown; gills developing reddish brown spots and stains, especially on their edges.
Tricholoma ustale
at Fungi of Poland

33.Cap otherwise colored; gills not developing reddish brown spots or stains.
34


34.Cap not streaked in appearance, smooth (without prominent fibers or scales); stem base (usually) pinkish or orangish.
35

34.Cap streaked in appearance and/or with prominent fibers or scales, at least over the center; stem base not pinkish or orangish.
37


35.Odor and taste sharply soapy; gills becoming yellowish with age but not pinkish; reported from California (elsewhere this taxon is reported under conifers).

35.Odor and taste not distinctive; gills developing pinkish hues and/or discolorations; reported from Michigan.
36


36.Cap bluish gray.
Tricholoma saponaceum
var. ardosiacum

36.Cap brownish.
Tricholoma saponaceum
"var. Ovrebo 413"


37.Mushroom identifier agrees not to blame the messenger on discovering that two or three species are virtually indistinguishable--with or without a microscope. (The mushrooms all grow east of the Rocky Mountains in beech-maple or oak-hickory woods, have gray or grayish caps with varying degrees of "fibrillosity" and "streakedness," have gills that may develop dark edges, taste bitter, lack an odor, have spores 6-8 x 5-6 µ, have cystidia on the gill edges, and lack clamp connections.)
38

37.Mushroom identifier not as above.
Bitter Gray Tricholoma


38.Cap whitish with gray, tan, or brownish areas, especially over the center; gills white at first.
Tricholoma serratifolium

38.Cap more evenly gray than above; gills off-white at first.
39


39.Cap often broadly bell-shaped at maturity, light to medium gray, with prominent fibers over the center and on the margin; gills without pinkish shades when young.
Tricholoma acre

39.Cap not broadly bell-shaped at maturity, darker gray than above, with prominent fibers over the center and pressed-down fibers elsewhere; gills often with pinkish shades when young.
Tricholoma pullum


40.Cap brown, brownish, tan, or reddish brown at maturity.
41

40.Cap gray, grayish, purplish gray, or blackish at maturity.
52


41.Cap with prominent, radiating, tan to brownish fibers over a whitish to buff ground color; gills not discoloring at maturity; recorded from the Great Lakes states.

41.Cap not as above; gills often discoloring by maturity; variously distributed.
42


42.Mycorrhizal with poplars (primarily with Narrowleaf Cottonwood, but possibly with Quaking Aspen) in sandy soil in western North America; cap tan to dull reddish brown; stem whitish, staining and bruising dull reddish brown.
Tricholoma populinum
at Fungi of Poland

42.Not completely as above.
43


43.Gills pale to bright yellow, discoloring reddish brown with age; cap yellowish brown when young, darkening to brown or reddish brown; found in oak-hickory and beech-maple woods, also under birch; reported from the Great Lakes states and the Pacific Northwest--but "[c]ollections identified at T. fulvum in California are most likely T. nictitans" (Shanks).

43.Not completely as above.
44


44.Mushroom identifier wants to consider two reddish brown species from eastern North America that have not been well documented, or even described in the fresh state, for about 100 years.
45

44.Mushroom identifier not as above.
46


45.Cap the color of pale leather according to the species author (Peck), "dark reddish brown" according to Ovrebo (1980); spores 3 µ long as measured by Peck with this microscope, 5 x 3-4 µ as measured from the stem apex 91 years later by Ovrebo with an oil immersion microscope (and as measured in his own contemporary collections); gills "not spotted or changeable" according to Peck, often spotted or discolored orange-brown according to Ovrebo; found in "woods" (Peck), "frondose woods" (Kauffman), or under paper birch or eastern white pine (Ovrebo).
Tricholoma terriferum

45.Cap leather colored when young, becoming brownish or reddish, according to the species author (Peck), "reddish brown or tawny red" according to Kauffman (1918), not described by contemporary authors; spores 5 µ long as described by Peck, 7 x 5 µ as measured from the stem apex of the type collection by Ovrebo; gills spotting reddish; found "in frondose woods, sometimes forming mycorhiza on the roots of black oak" (Kauffman).
Tricholoma transmutans


46.Mycorrhizal with Coast Live Oak; on the West Coast; cap pale orangish or buff at first, darkening in patches to brownish orange, eventually brownish overall; gills whitish, spotting brownish; stem whitish at apex, elsewhere darkening to brownish from the base up.

46.Not completely as above.
47


47.Stem at maturity whitish overall, sometimes with a dingy base.
48

47.Stem at maturity brownish to reddish brown, yellowish brown, or brownish salmon, at least over the bottom half.
49


48.Cap slimy when fresh, often somewhat wrinkled or corrugated, dark brown, usually with olive brown shades; gills white to buff but not yellowish, often discoloring brownish on their edges; found in beech-maple or oak-hickory woods in the Great Lakes states.
Tricholoma olivaceobrunneum

48.Cap dry, sometimes with pressed-down fibers but not wrinkled or corrugated, "buff brown to light golden brown" (Ovrebo); gills light buff to pale yellow, discoloring brownish on their edges; recorded from beech-maple woods in Michigan.
Tricholoma subaureum


49.Cap slimy when fresh and young (in dry conditions or when young specimens are unavailable, check cap surface for appressed leaves and debris, or check microscopically for a gelatinous matrix).
50

49.Cap dry in all stages of development.
51


50.Gills whitish before discoloring.

50.Gills pinkish buff before discoloring.
Tricholoma pudorinum


51.Cap light pinkish to salmon underneath brown fibers, sometimes greenish at the margin; gills light buff, discoloring and bruising salmon; stem whitish above, salmon below; cystidia present only on gill edges.
Tricholoma insigne

51.Cap yellowish brown to brown over the center, paler brown elsewhere, sometimes yellow or yellowish green on the margin; gills buff to gray, in age becoming yellow near the cap margin and sometimes overall, discoloring brownish on their edges; stem whitish, becoming yellowish brown in places; cystidia present on both gill edges and faces.
Tricholoma luteomaculosum


52.Found east of the Rocky Mountains.
53

52.Found in western North America.
55


53.Stem whitish, not discoloring, with silky whitish fibers but without darker fibers or scales; cap slimy when fresh and young; gills whitish becoming yellowish when overmature.
Tricholoma marquettense

53.Not completely as above.
54


54.Gills at first buff to light gray, sometimes becoming flushed with salmon shades, the edges often discoloring grayish; stem whitish with grayish to brown scales; cystidia absent; clamp connections absent.

54.Gills dull white, not discoloring; stem white with grayish fibers; cystidia sometimes present on gill edges; clamp connections present.
Tricholoma huronense


55.Cap dry in all stages of development, with an inrolled and bearded margin when young; gills white to pale gray, not discoloring; stem grayish with blackish scales and fibers; stem base often becoming red when dried; cystidia and clamp connections absent.
Tricholoma atrosquamosum

55.Not completely as above.
56


56.Cap at maturity dark gray to purplish gray, not wrinkled; gills white, discoloring pinkish brown to grayish orange; stem white, discoloring pale orange at the base; in California associated with oaks.

56.Cap at maturity medium to dark gray, without purplish hues, often radially wrinkled; gills white, discoloring pale golden brown; stem white, discoloring pale golden brown; in California associated with Tanoak or in mixed evergreen forests.
Tricholoma mutabile


 [No ring, conifers . . . ]
 

57.Stem base often tapered and rooting, usually discoloring pinkish to orangish inside and out at maturity; gills widely spaced and thick, whitish but sometimes developing yellow, olive, or reddish discolorations; taste and odor usually strongly soapy, but sometimes mild or mealy; cap surface fairly smooth (not densely hairy or scaly) but sometimes cracking up in age; cap color extremely variable but usually with gray and green shades predominating; cystidia absent; clamp connections present.

57.Not completely as above.
58


58.Cap yellow, yellowish, or greenish--or yellow to greenish underneath darker fibers or scales.
59

58.Yellow to greenish shades absent from cap.
67


59.Odor strong and unpleasant, reminiscent of coal tar; taste disagreeable but not mealy; cap dry and fairly smooth, pale yellow with a darker center; found in western North America.
Tricholoma sulphureum
at Fungi of Poland

59.Not completely as above.
60


60.Found in coastal California; cap yellowish with a brownish center and pressed-down fibers (often streaked in appearance); taste mealy; gills white, discoloring yellowish; stem whitish with a pinkish or orangish base, discoloring brownish.
Tricholoma tumidum

60.Not completely as above.
61


61.Taste not mealy (mild or bitter).
62

61.Taste mealy.
63


62.Cap densely hairy over the center, with pressed-down fibers elsewhere, light yellowish green with a brownish center; gills usually yellowish but occasionally whitish, often discoloring on their edges; taste bitter; widely distributed in North America; cystidia present on gill edges.
Tricholoma aestuans

62.Cap fairly smooth, with occasional small fibers or scales, yellow with a smoky brown center; gills usually whitish but occasionally yellowish, often discoloring on their edges; taste mild or bitter; found east of the Rocky Mountains; cystidia absent.
Tricholoma fumosoluteum


63.Cap with prominent pressed-down fibers.
64

63.Cap fairly smooth--with a few minute fibers or scales, but not as above.
66


64.Gills and stem greenish yellow (sometimes discoloring pinkish); stem base tinged pinkish to purplish red inside and out; cap sharply bell-shaped, grayish green over the center, yellowish to greenish elsewhere.
Tricholoma davisiae

64.Not completely as above.
65


65.Fibers dark gray to blackish over a yellowish to greenish ground color, creating a streaked appearance.

65.Fibers colored like the ground color, which is medium yellow.
Tricholoma subluteum


66.Gills yellow; stem usually yellow (rarely white).

66.Gills white; stem usually white, at least over the upper half.
Tricholoma intermedium


67.Cap slimy when fresh, orange or orangish; stem appearing "sheathed" with distinctive small scales that are colored like the cap but terminate near the apex, leaving a white zone at the top; gills discoloring brownish; odor mealy; taste mealy or bitter.

67.Not completely as above.
68


68.Odor strong and unpleasant, reminiscent of coal tar.
69

68.Odor not as above (mild, mealy, fragrant).
70


69.Cap yellowish when young but soon fading to buff with a tan center; gills yellowish, fading to buff; stem with yellow shades in all stages of development.

69.Cap creamy white to pale tan in all stages of development; gills without yellow shades; stem whitish.
Tricholoma inamoenum


70.Cap white or whitish overall.
71

70.Cap more highly colored.
75


71.Cap dry and velvety-hairy, pure white; gills white; stem white with a brownish base at maturity; odor and taste mild; described from Mexico; clamp connections present.
Tricholoma albidulum

71.Not completely as above.
72


72.Cap with tan to brown fibers or scales over a white ground color.
73

72.Cap with white fibers or scales--or cap smooth.
74


73.Cap with "uniformly scattered" dark brown to blackish scales over a buff to grayish buff ground; cystidia present on gill edges.

73.Cap with "appressed radiating" pale brown fibers over a whitish ground; cystidia absent.


74.Cortina present when very young; cap 4-7 cm across, white, bruising yellowish brown; gills white, discoloring yellowish by maturity; stem white, the base discoloring yellowish with maturity; taste acrid; European species (probably; European authors do not mention the cortina) recorded once from North America in a Michigan conifer plantation; cystidia absent.
Tricholoma albatum

74.Cortina apparently absent but cap margin with partial veil remnants when young; cap small (1-3.5 cm across), pure white; gills and stem white; odor and taste mild; recorded from Oregon; cystidia present on gill faces and edges.
Tricholoma cystidiosum


75.Cap gray or grayish (sometimes nearly black).
76

75.Cap brown, brownish, reddish brown, tan, cinnamon, or pinkish buff.
91


76.Taste usually acrid or bitter (sometimes slowly).
77

76.Taste usually mild or mealy.
79


77.Cap conspicuously hairy to scaly, dark gray.
Tricholoma atrodiscum

77.Cap smooth or with inconspicuous, pressed-down fibers (sometimes streaked in appearance), pale to medium gray.
78


78.Cap sharply bell-shaped at maturity, streaked in appearance.

78.Cap flat, convex, or rarely broadly bell-shaped at maturity, not streaked or streaked irregularly.
Tricholoma argenteum


79.Flesh turning promptly reddish when sliced; cap dry, often with purplish shades mixed with gray; stem white to pale gray, discoloring yellowish brown; taste mealy; found in the Pacific Northwest and California.

79.Not completely as above.
80


80.Stem with blackish fibers or scales on the upper half, whitish below; cap moist, usually streaked in appearance; gills white, their edges often discoloring blackish; taste mealy; recorded from Oregon.
Tricholoma nigrum

80.Not completely as above.
81


81.Cap slimy when fresh and young (in dry conditions or when young specimens are unavailable, check cap surface for appressed needles and debris, or check microscopically for gelatinized hyphae).
82

81.Cap dry in all stages of development.
85


82.Stem usually developing yellow or yellowish tints.
Tricholoma portentosum
at Fungi of Poland

82.Stem not usually developing yellow shades.
83


83.Cap not conspicuously wrinkled; gills not discoloring; recorded from Idaho (presented as a new species in Ovrebo's 1973 masters thesis and not later validly republished).
"Tricholoma nigrocystidiosum"

83.Cap conspicuously wrinkled; gills discoloring yellowish or pale brownish with age; variously distributed.
84


84.Stem pure white, not discoloring; recorded from the Great Lakes states and Mississippi.
Tricholoma marquettense

84.Stem whitish, discoloring pale brownish; recorded from California, Washington, and Michigan.
Tricholoma mutabile


85.Young cap margin inrolled and bearded.
86

85.Young cap margin not as above.
87


86.Stem covered with blackish fibers, base often turning bright red when dried; gills grayish, not discoloring blackish; spores 5-8.5 µ long; cystidia absent.
Tricholoma atrosquamosum
= T. nigromarginatum

86.Stem white or grayish, without blackish fibers; gills grayish, discoloring gray to blackish in spots; spores 7-10.5 µ long; cystidia sometimes present on gill edges.


87.Mushroom identifier can think of something better to do with her time than search for erudite microscopic distinctions between virtually identical species.
Mealy Gray Tricholoma

87.Mushroom identifier is a true mushroom geek.
88


88.Cortina absent; clamp connections present. (Note: Cortinas in Tricholoma are often very hard to observe except on the youngest of specimens. "Tricholoma terreum" appears in field guides as lacking a cortina, but that name represents a European species that does not occur in North America, according to Shanks; the mushrooms in question are probably Tricholoma pardinum or Tricholoma myomyces, below.)

88.Cortina present; clamp connections absent.
89


89.Cap with moderately spaced fibers and scales; gills sometimes yellowing with age; spores 5-7 µ long; pseudoparenchymatous subcutis (don't ask) absent.
Tricholoma scalpturatum
at Fungi of Poland

89.Cap with densely arranged fibers and scales; gills rarely discoloring yellowish; spores larger than above; pseudoparenchymatous subcutis present.
90


90.Gills sometimes discoloring gray on their edges; cystidia present on gill edges; recorded from coastal and montane areas of northern California.
Tricholoma myomyces
var. cystidiosum

90.Gills without gray edges (rarely discoloring yellowish); cystidia absent; widely distributed in northern North America.


91.Gills not discoloring by maturity.
92

91.Gills discoloring brownish, yellowish brown, cinnamon brown, or reddish brown by maturity.
93


92.Cap sharply bell-shaped, usually with greenish or yellowish shades mixed with brown; gills and stem yellowish green, at least when young.
Tricholoma davisiae

92.Cap convex or flat, with brownish fibers over a whitish ground color; gills and stem whitish.


93.Cap small (1.5-4 cm across), yellowish brown with orange mixed in, especially over the center; taste mild or acrid; stem with rusty orange fibers that darken on handling or with age; mycorrhizal with Douglas-Fir in western North America.
Tricholoma psammopus
at Fungi of Poland

93.Not completely as above.
94


94.Stem with a ring zone, whitish above and orangish brown below; cap reddish brown; taste bitter; cortina present on young specimens; recorded from California.

94.Not completely as above.
95


95.Cap prominently wrinkled, olive brown, slimy when fresh and young; stem white, not discoloring (but sometimes dingy near the base); gill edges becoming brownish; recorded from the Great Lakes states and Mississippi.
Tricholoma olivaceobrunneum

95.Not completely as above.
96


96.Cap brown to yellowish brown, without reddish hues.
97

96.Cap reddish brown, rusty brown, or cinnamon brown.
98


97.Recorded from the Pacific Northwest; gills whitish with brownish edges at maturity; cap usually bell-shaped; stem pale, discoloring brownish.
Tricholoma subumbrinum

97.Recorded from the Great Lakes states; gills buff, discoloring cinnamon brown; cap convex or flat; stem buff at the apex, light tan below (recorded as a new species in Ovrebo's doctoral dissertation but not later validly republished).
"Tricholoma muskokense"


98.Cap slimy when fresh and young (in dry conditions or when young specimens are unavailable, check cap surface for appressed needles and debris, or check microscopically for gelatinized hyphae).
100

98.Cap dry in all stages of development.
99


99.Partial veil present, leaving remnants on the margins of young caps; young caps often sharply bell-shaped; stem almost always hollow by maturity; cap surface almost always breaking up into small scales.

99.Partial veil absent; young caps convex; stem only occasionally hollow; cap surface usually less scaly than above.


100.Base of stem elongated and rooting into the soil.
101

100.Base of stem not rooting.
102


101.Gills pale yellow to buff; spores 6-8 x 4-5 µ; widely distributed.
Tricholoma nictitans
(see Tricholoma fulvum)

101.Gills orangish white; spores 5-7 x 3-4 µ; recorded from California.


102.Caps medium to large (5.5-11 cm across); spores 5 x 3 µ; recorded only east of the Rocky Mountains.
Tricholoma terriferum

102.Caps small to medium (2.5-10 cm across); spores 5-7 x 3-4 µ; widely distributed.



References

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Kuo, M. (2004, December). The genus Tricholoma. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/tricholoma.html

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