The Genus Tricholoma in North America

The Genus Tricholoma in North America 

Steve Trudell 

Note: Most of the material presented 

in this article has been taken, with 

modification, from Tricholomas of North 

America: A Mushroom Field Guide, by 

Alan Bessette, Arleen Bessette, Bill Roody, 

and Steve Trudell, newly published by the 

University of Texas Press. 

Most tricholomas are large 

showy mushrooms that 

readily attract the attention of 

mushroom hunters. Although only a few 

are popular edibles, all tricholomas are 

very important ecologically because of 

their ectomycorrhizal associations with 

many of the dominant temperate and 

boreal forest tree species. Unfortunately, 

when it comes to naming them, probably 

every North American field mycologist 

has struggled with the identification of 

Tricholoma species and “Tricholoma sp.” 

is a common feature of foray displays 

and species lists. By and large, the 

greatest obstacle has been a lack of 

readily available reference materials, 

especially those having illustrations in 

color, which is particularly valuable for 

distinguishing many tricholomas that 

are otherwise similar in size, stature, and 

other morphological characters. 

Far more than 100 species of 

Tricholoma have been reported from 

North America, although the list of 

well documented taxa is much shorter. 

Tricholomas often are referred to as 

trichs (pronounced either “tricks” or 

“trikes”), although some field guides call 

them cavaliers or knights. They grow on 

the ground near certain types of trees 

and typically fruit from late summer 

through early winter or even into spring 

in warmer areas. A few of them are fine 

edibles, while others are inedible or 

even poisonous. However, the edibility 

of the majority of our tricholomas is not 

well known. 

Tricholoma (Fries) Staude 

What we know as the genus, 

Tricholoma, originated with Elias 

Magnus Fries in his 1821–1832 

publication, Systema Mycologicum. In 

this early version of Fries’s classification 

system, Tricholoma constituted one 

of 36 tribes (Tribe V) within the huge 

genus, Agaricus, which included nearly 

all of the gilled mushrooms. 

Fries defined Tricholoma as including 

fungi that produce white-spored 

terrestrial mushrooms that are fleshy 

and relatively robust. They lack a 

universal veil (so there is no volva on 

the stalk base or warts/patches on the 

cap) and either lack a partial veil or 

have one that is fibrillose or floccose 

and disappears early, sometimes leaving 

remnants on the margin of the cap. 

The cap is hemispherical to obtusely 

flattened or, when young, somewhat 

bell-shaped with a thin incurved 

margin. The gills are of unequal length 

and emarginate or rounded where they 

approach the stalk. The stalk is not 

smooth, but rather is fibrillose, scaly, 

or has coarse longitudinal striations 

formed by aggregated fibrils, and 

its flesh is confluent with that of the 

cap. The mushrooms exhibit diverse 

colors. Including additions in his 

later publications, Fries’s Tricholoma 

eventually included over 100 species. 

The name, “tricholoma,” is derived 

from two Greek roots—tricho (thrix) 

= hairy and loma = border or fringe— 

referring to the fibrillose partial veil 

remnants found on the cap margin in 

several species. Interestingly, however, 

most tricholomas do not exhibit this 

feature. 

Another of Fries’s tribes—Tribe III, 

Armillaria—also is important in the 

history of Tricholoma. The principal 

difference between Fries’s armillarias 

and tricholomas is the existence in 

the former of a membranous partial 

veil that leaves a ring on the stalk. Not 

surprisingly, over time, taxonomists have 

done a lot of shuttling of species between 

Armillaria and Tricholoma, such that 

now a number of the Friesian armillarias 

reside in Tricholoma. 

Tricholoma is considered to have 

become a genus in 1857 with the 

publication of Friedrich Staude’s 

Die Schwämme Mitteldeutschlands 

insbesondere des Herzogthums Coburg. 

However, Paul Kummer and Lucien 

Quélet each appear as the genus 

authority in some publications. The 

type species for the genus is Tricholoma 

flavovirens (Persoon) S. Lundell, which 

currently is thought to represent the 

same species as T. equestre (Linnaeus) 

P. Kummer. A recent analysis concluded 

that, if the two names are in fact 

synonyms, then T. equestre should be 

used because it is the earlier of the two 

(Deng and Yao, 2005). 

The current concept of Tricholoma 

differs little from Fries’s view of it— 

fleshy terrestrial mushrooms with a 

white spore-print, smooth, inamyloid 

spores, parallel gill trama, and (mostly) 

emarginate or sinuate gill attachment. 

The typical tricholoma stature features 

a broadly umbonate cap that is wide 

relative to the length of the stalk and a 

Fig. 1. Examples of gill attachment. Top row, left to right: free, adnexed, 

adnate. Bottom row, left to right: notched or sinuate, decurrent. Although 

tricholomas typically have notched or sinuate gills, many will be found 

with adnexed gills, and some will even appear to be free. Illustration by 

Marsha Mello. 

Winter 2012 • Volume 5:5 • FUNGI 

23

Fig. 2. Tricholoma subresplendens, one of the white-capped tricholomas. It 

is a W.A. Murrill species that is very similar to, or perhaps the same as, T. 

columbetta. Photo by Bill Roody. 

“gutter” around the stalk formed by the 

emarginate gills. Because the concept 

now is based in part on microscopic 

features (mostly their absence), 

sometimes it is necessary to use a 

microscope to be certain that you 

have a tricholoma. 

In paperback 

February 1, 2013 

24 FUNGI • Volume 5:5 • Winter 2012 

Although gill attachment is rarely, 

if ever, used to help differentiate 

species within Tricholoma, it is an 

important character for recognizing the 

genus. Usually it is described as being 

emarginate, notched, or sinuate (Fig. 1). 

Unfortunately, gill attachment can be a 

rather variable feature and these terms 

have been interpreted differently from 

mycologist to mycologist (Leonard, 

2000). C.H. Kauffman (1918) described 

the variability nearly a century ago. 

“Theoretically, they (the gills) are always 

emarginate behind, but this condition 

varies considerably. It is true that, in the 

mature plant, when the pileus is fully 

expanded, they become either sinuate 

or emarginate in most cases, although 

a single specimen may not always be 

normal in this respect. When young, 

however, they often do not show this 

character clearly, but are then adnexed, 

rounded-adnate, or adnate in such a way 

that they are merely a little less broad 

at the attached portion than they are 

a few millimeters from the stem, and 

this short distance is often marked by 

a straight edge rather than a rounded 

edge... In old stages the gills may even 

become spuriously decurrent.” Thus, 

when attempting to determine the gill 

attachment of a putative tricholoma, it 

is best to examine multiple specimens 

of different ages and to allow for some 

latitude in interpretation. 

Macroscopic Features Used for 

Classifying and Identifying Tricholomas 

Identification of tricholomas relies 

heavily on size of the fruitbody and 

macroscopic features of the cap such as 

color, the presence or absence of scales 

or radiating fibrils on the surface, and 

whether it is dry, moist, or viscid. Odor 

and taste of the flesh are sometimes 

defining characters. The gills are white 

to off-white in most species but can also 

be grayish, buff, or yellow. Spotting, 

staining, or discoloring (often reddish 

brown) of the gills in age (or after 

damage) is a characteristic feature of 

many species. 

Size of the fruitbodies can vary within 

a species and so exact measurements 

are not always useful. However, “small,” 

“medium,” and “large,” based on the 

diameter of the mature caps, are handy 

descriptors. Typically, “small” refers to 

caps with diameter usually less than 5 

cm; “medium” to caps usually between 

5 and 10 cm, and “large” to caps usually 

greater than 10 cm. 

The stalk is usually more or less 

equal but may be swollen in the middle 

(ventricose), tapered downward, or 

enlarged to slightly bulbous at the 

base. It is fleshy or fibrous like the cap 

and can be solid, stuffed, or hollow. Its 

surface usually is dry and longitudinally 

striate, but also can be nearly smooth, 

appressed-fibrillose, scaly, or slightly 

scurfy (at the apex only). Stalk color 

often is white, but it may be tinged 

with the cap color, or, more rarely, fully 

concolorous with the cap. 

A number of tricholomas have a 

cortina. In these species, the veil usually 

is delicate and may be visible only on 

very young specimens, leaving just a 

trace of fibrils as a faint ring-zone on the 

upper portion of the stalk or a fringed 

margin on the cap. A few species have a 

more substantial membranous veil that 

leaves a more or less prominent ring on 

the stalk. 

Staining of the cap surface or, 

more commonly, the gills and 

stalk, from bruising, handling, or 

with age is sometimes important 

in distinguishing between species. 

Color-change reactions following 

the application of chemicals to the 

fruitbody (“macrochemical” reactions) 

are not used widely in identifying

Fig. 3. Tricholoma arvernense, one of the yellow-capped 

tricholomas. It was added to the North American list 

only recently when a DNA sequence from a collection 

made in Idaho by Andrew Parker was found to be 

nearly identical to that of European material. It also has 

been found in California, Oregon, Washington, Alaska, 

and possibly Newfoundland. Photo by Sava Krstic. 

tricholomas, but can be important in some cases. Potassium 

hydroxide (KOH), ammonium hydroxide (NH4OH), and 

paradimethylaminobenzaldehyde (PDAB) are of most use. 

Common odors of tricholomas include farinaceous, 

cucumber, coal tar, and, of course, the matsutake’s spicy 

cinnamon aroma. In many species, the odor is pleasant, 

although not easily describable. The more common tastes are 

mild, bitter, and farinaceous. 

In addition to these macromorphological features, knowing 

which species of tree the mushrooms were growing with can 

be critical for identifying them. When found beneath isolated 

trees, or in more or less pure stands, the associate is fairly 

obvious. However in mixed woodlands containing a variety 

of ectomycorrhiza-forming trees, it can be more difficult 

to determine a specific relationship. At a minimum, it is 

important to know whether the nearby trees were conifers or 

hardwoods, and so this information should always be included 

in your field notes. 

Microscopic Features Used for Classifying and Identifying 

Tricholomas 

Microscopic features are important for distinguishing 

the genus Tricholoma from other genera that are similar 

macroscopically. However, they generally are less distinctive, 

less variable, and less helpful for distinguishing species in 

Tricholoma than they are in many other genera. The spores 

are smooth and non-amyloid, cystidia are present only in 

some species (then usually cheilocystidia), and cap cuticle 

usually is radially filamentous. The shape and size of the 

spores and cystidia, the presence of clamp connections, and 

the structure of the cap cuticle (especially the presence of a 

so-called pseudoparenchymatous hypodermium) are the most 

commonly used microscopic features. 

Fig. 4. Tricholoma floridanum, another of the yellowcapped 

tricholomas. This is one of the many not-wellknown 

species described by W.A. Murrill from Florida. 

Photo by Alan and Arleen Bessette. 

Morphologically Similar Genera 

Following Fries’s initial definition of Tricholoma, some 

of the species he included in the genus were transferred to 

other existing or newly created genera, such as Calocybe, 

Dermoloma, Lepista/Rhodopaxillus, Leucopaxillus, 

Lyophyllum, Melanoleuca, Porpoloma, Rhodocybe, Tephrocybe, 

Tricholomopsis, and Tricholosporum. Because many of the 

mushrooms in these pale-spored genera share the essential 

macroscopic features of tricholoma, they can be mistaken for a 

tricholoma. Thus, the following brief descriptions summarize 

the key features for distinguishing them from tricholomas. 

Amanita—universal veil present, leaving a volva on the 

stalk base, and often warts or patches on the cap; skirt-like 

ring often present; gills free or nearly so, often seceding. Cap 

margin often striate. Most have an elegant gestalt, not easily 

described, but readily appreciated with a bit of experience. 

Armillaria (the honey mushrooms, formerly armillariella)— 

usually found on wood, often in clusters, tough black 

“bootlace” rhizomorphs often present in substrate, the 

typical honey colors of their fruitbodies are rare or absent in 

tricholomas, gills adnate to decurrent. 

Calocybe—white or brightly colored fruitbodies, basidia 

contain siderophilous granules, spores sometimes roughened, 

cap cuticle sometimes cellular. 

Catathelasma—large, hard-textured mushrooms, adnate to 

decurrent gills, stalk tapered downward and with double ring, 

amyloid spores. 

Clitocybe—gills usually decurrent and fruitbodies often 

funnel-shaped, at least at maturity. 

Collybia sensu lato (including gymnopus and 

rhodocollybia)—cap margin incurved to inrolled (at least when 

young), stalk with a cartilaginous rind, gills adnexed to adnate, 

spores usually pinkish in rhodocollybia. 

Dermoloma—smallish fruitbodies, cap cuticle hymeniform 

(radially filamentous in tricholomas), spores amyloid in some 

species. 

Floccularia—spores amyloid, stalks typically floccose, 

usually with a membranous ring. 

Hygrophorus (sensu stricto, the medium to large, mostly 


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Fig. 5. Tricholoma “quercetorum," another yellowcapped 

species. As the epithet suggests, it occurs with 

oaks. It has not yet been described formally and, when 

it does, it will need a new epithet as "quercetorum" 

already is in use for a different (European) species. 

Photo by Noah Siegel. 

dull-colored species)—gills thick and waxy-looking, adnate to 

decurrent, gill trama divergent when young. 

Laccaria—fruitbodies with distinctive orange-brown, pinkishbrown, 

or purplish colors that are rare or absent in Tricholomas, 

gills thick and waxy-looking, usually pinkish brown, lilac, or 

purple, stalk rather tough and fibrous, spores spiny. 

Lepista—spore-print with pinkish tones, spores roughened. 

Leucopaxillus—abundant mycelial cords or mat often 

present at base of stalk, fruitbodies often very firm and slow to 

rot, spores amyloid, sometimes roughened. 

Lyophyllum (including tephrocybe)—basidia contain 

siderophilous granules, fruitbodies usually dull colored and 

often with greasy appearance, many species stain black. 

Megacollybia—usually found on wood (may be well rotted), 

gills rather broad, their edges with abundant cystidia. 

Melanoleuca—cap hygrophanous and often broad relative 

to stalk length, spores amyloid, roughened, gills usually with 

abundant cystidia. 

Porpoloma—spores amyloid, gill edges typically with 

cystidia. 

Tricholomopsis—usually found on wood, often bright 

yellowish, gill edges often with abundant cystidia. 

Tricholosporum—spores angular, or shaped like crosses. 

In addition to these pale-spored genera, many entolomas 

and hebelomas have the same stature as a typical tricholoma. 

However, they are easily recognized by their salmon/pinkish 

brown and dull brown spores, respectively. Small brownish 

tricholomas can appear very inocybe-like but, again, sporecolor 

(brown in inocybes) quickly separates them. 

Subdivision of Tricholoma 

Tricholoma has been divided into subgroups since its 

creation. In Systema Mycologicum (1821–1832), Fries 

recognized four groups based on the nature of the cap surface. 

In Epicrisis Systematis Mycologici (1836–38), he recognized 

seven groups, mostly based on the nature of the cap surface, 


Fig. 6. Tricholoma nigrum, one of the gray-capped 

tricholomas. This little-known species was described in 1996 

by Kris Shanks and Clark Ovrebo from material collected 

in Oregon. It now is known from Washington, and possibly 

Newfoundland, as well. Photo by Steve Trudell. 

but also including consideration of such things as season of 

occurrence and the fleshiness, fragility, and shape of the cap. 

Each of these groups was then divided further based on color, 

width of the gills, and discoloration of the gills. For the most 

part, Fries retained this latter classification in his later works, 

although he did make minor revisions, changed some names, 

and moved some species around. 

Most mycologists of the late 1800’s and early 1900’s, 

including Charles Horton Peck and C.H. Kauffman in the 

United States, divided the genus in ways very similar to Fries’s 

scheme. Additional macroscopic features such as odor, taste, 

size, and color were utilized in many of these groupings. Of 

course, as genus definitions evolved and species were moved 

(mostly) out of Tricholoma, the changing species composition 

of the genus was reflected in its subdivision. In parallel with 

the new genus alignments based on microscopic features, the 

subdivision of Tricholoma also began to reflect microscopic 

features, such as the presence of clamp connections, anatomy 

of the cap cuticle, and location of pigments in the colored 

species (inside or outside of the hyphae). 

Because many of the features that have been used to define 

the subgroups are gradational and not always easy to apply, 

Kauffman (1918) observed that, “The grouping of this large 

genus is fraught with considerable difficulties.” At present, 

perhaps the two most widely used subdivisions of the genus 

are those by Marcel Bon (1984) and Rolf Singer (1986). 

These are likely to be revised substantially, or even replaced, 

as the results of molecular studies and morphologicalmolecular 

integration lead to increased understanding 

of the evolutionary relationships within the group. For 

identification purposes, division into four groups based on 

cap color—white/silver, yellow, gray, and brown—provides a 

practicable, albeit artificial, scheme (Figs. 2–9). 

History of the Study of Tricholoma 

in North America 

Despite the fact that tricholomas are among the more 

conspicuous of our woodland fungi, the genus historically 

has received relatively little attention in North America.

Fig. 7. Tricholoma niveipes, another gray-capped 

species. It occurs in sandy quartz-rich soils and like 

many mushrooms in such habitats, has a strong 

farinaceous odor in the mycelium as well as the 

fruitbody. Photo by Bill Roody. 

Fig. 8. Tricholoma transmutans, one of the browncapped 

tricholomas. This relatively little-known 

species, described by C.H. Peck, appears to be 

widespread in the northern USA and Canada. For 

instance, it is said to be perhaps the most common 

tricholoma in Québec. Photo by Bill Roody. 

Charles Horton Peck described over 60 Tricholoma species 

in the late 1800’s and early 1900’s, although many of them 

later were transferred to other genera. In what still is the only 

comprehensive treatment of the genus in North America, 

William Alphonso Murrill prepared the “Tricholoma” section 

of the North American Flora (1914), under the genus names 

Melanoleuca and Cortinellus. Thus, many non-tricholomas (in 

the current sense) were included in Murrill’s compilation. 

C.H. Kauffman’s Agaricaceae of Michigan (1918) included 

an extensive treatment of the tricholomas of the Great Lakes 

region. During his prolific career, Alexander Smith of course 

studied the genus and described a number of species. However, 

he did not deal with it in a comprehensive fashion. 

Probably the most active North American student of 

Tricholoma over the past few decades has been Clark Ovrebo. 

His master’s thesis (1973) and Ph.D. dissertation (1980) 

covered the tricholomas of the Pacific Northwest and the 

Great Lakes region, respectively. Since completing his graduate 

studies, Ovrebo has continued work on the genus and has 

published a number of articles, describing new species and 

interpreting some of Peck’s species concepts. 

Kris Shanks surveyed the tricholomas of California for 

her master’s degree (1994) and later published the bulk of 

her thesis as a fascicle of the Agaricales of California series 

(1997). A number of other mycologists, including Tim Baroni, 

Howard Bigelow, Roy Halling, and Scott Redhead have made 

contributions to our knowledge of Tricholoma in North 

America. In addition, amateur mycologists have helped expand 

our understanding in areas such as the northeastern USA 

(Ed Bosman), southeastern Canada (Yves Lamoureux and 

Jean Després), and Pacific Northwest (Charles Volz, Coleman 

Leuthy, Paul Kroeger, and Andrew Parker). 

Ecology of Tricholomas 

It is believed that all tricholomas are ectomycorrhizal or, 

in some cases, arbutoid mycorrhizal, forming a mutually 

beneficial association with many trees, some shrubs, and 

possibly even some herbaceous plants. Thus, they are nearly 

always found where trees are present, most often in forests and 

parks. Among the trees known to partner with tricholomas 

are oak, beech, birch, willow, aspen, cottonwood/poplar, pine, 

spruce, fir, hemlock, and Douglas-fir. 

Beyond their association with forest trees, not much 

is known about the habitat requirements of tricholomas. 

However many of them, such as the matsutake, occur in very 

nutrient-poor soils such as those with a high proportion 

of quartz sand. In many areas, tricholomas are among the 

late-season fruiters, along with species of Cortinarius and 

Hygrophorus. For instance, in a 5-year survey of Gwaii Haanas 

National Park in Haida Gwaii (formerly known as the Queen 

Charlotte Islands, located off the coast of British Columbia) 

conducted by Paul Kroeger, Bryce Kendrick, and others, the 

Tricholoma species count increased from 2 to 13 in a single 

season when collecting extended beyond September into late 

October and November (in most years, access to Gwaii Haanas 

National Park is not allowed after mid-September). 

Interestingly, some tricholomas serve as hosts for mycoheterotrophic 

plants such as Monotropa hypopitys (pinesap, 

Fig. 10) and Allotropa virgatum (candystick, Fig. 11). In these 

associations the plants, which do not contain chlorophyll and 

thus cannot make their own food via photosynthesis, obtain 

both their carbon compounds and other nutrients from the 

fungus partner. Consequently, these plants are considered 

parasites, although the possibility that they are contributing 

some as-yet unrecognized benefit to the fungi cannot be 

ruled out. 

Edibility of Tricholomas 

Tricholoma includes many large fleshy mushrooms, and 

some of them are common and often abundant. Because of 

this, they are likely to attract the attention of those who collect 

wild mushrooms for food. Unfortunately, tempting as they 


27

Fig. 9. Tricholoma grave, another brown-capped 

species. It is a very large and not-well-known species 

described by C.H. Peck. Photo by Noah Siegel. 

Fig. 10. Monotropa hypopitys (pine sap), a mycoheterotrophic 

plant that associates with species of 

Tricholoma such as T. flavovirens, T. portentosum, T. 

saponaceum, T. sejunctum, and T. terreum. Photo by 

Steve Trudell. 


Fig. 11. Allotropa virgata (candystick), a mycoheterotrophic 

plant that apparently associates 

exclusively with Tricholoma magnivelare, the American 

matsutake. Photo by Steve Trudell. 

may appear, relatively few members of the genus are known 

to be particularly good edibles. The edibility of many species 

is unknown, some are decidedly toxic, and one has proven 

deadly under certain circumstances. Add to this that edible 

tricholomas can be difficult to distinguish from those that are 

suspect or poisonous, and it becomes clear why they are not 

widely gathered for the table. 

The principal exceptions are T. magnivelare, T. portentosum, 

and T. equestre/flavovirens. Tricholoma magnivelare (Fig. 

12) is the highly prized American matsutake, which some 

mycophagists consider to be among the best of all edible wild 

mushrooms. Its characteristic spicy aroma has been famously 

described by David Arora as “a provocative compromise 

between ‘red hots’ and dirty socks.” 

The gastronomic quality of matsutake’s close relative, T. 

caligatum, has received mixed reviews. Often it has been 

described as intensely bitter and/or acrid and unpalatable. 

However, at other times it has been said to be mild, palatable, and 

even an excellent edible. Tricholoma caligatum is highly variable 

morphologically and it may be that different populations differ 

in their palatability. It also is possible that there is more than one 

species going by that name. 

Tricholoma portentosum (Fig. 13) is a widely distributed 

edible that, particularly in the East, can be quite common 

beneath pines from late fall into winter. It is appreciated both 

for its flavor and availability well after most other edible wild 

mushrooms have finished fruiting for the season. Sometimes it

can be found together with the lesser known T. intermedium, 

also a good edible. 

Although no tricholoma is known to be dangerously 

poisonous when consumed in small amounts, one widely 

eaten species, T. equestre/flavovirens (Fig. 14), surprisingly 

has been implicated in fatal incidents in Europe. Historically, 

this seemingly widespread mushroom has been regarded by 

many (outside of Japan, at least) as the best edible in the genus. 

However, in 2001, Bedry and others reported a dozen cases of 

poisoning, including three fatalities, in France, all following 

consumption of several consecutive meals that included large 

amounts of T. equestre/flavovirens. The victims experienced 

severe rhabdomyolysis, a disease that destroys muscle tissue. 

Similar poisonings also have been reported from Poland. 

Nothing resembling the European incidents has been reported 

from North America. However, despite the clean record here, 

caution would suggest avoiding T. equestre/flavovirens until 

the reasons behind the puzzling occurrence of the European 

poisonings are known. At a minimum, one should not eat large 

amounts of this, or any other, mushroom repeatedly over a 

short (on the order of a few days) time. 

The North American Species 

Currently, it is not possible to provide complete or definitive 

coverage of Tricholoma for a number of reasons. For one, 

compared to the situation in Europe, North American 

mushrooms are poorly known and nearly all groups are in 

need of much additional study, particularly the brown-capped 

species around T. pessundatum and the gray-capped species 

around T. myomyces. For another, mushroom systematics 

(naming, classifying, and study of their evolutionary 

relationships) is in a state of rapid flux. Analysis of the large 

amount of DNA sequence and other molecular data being 

produced is leading to many changes in how we view the 

evolutionary relationships among mushroom fungi and, 

as a result, in their classification and names. Fortunately, 

Tricholoma has been affected much less by these developments 

so far than many other mushroom groups and so the impact 

on mushroom hunters has not been great—but that is likely to 

change before long, so be prepared. 

For now, a bigger issue comes from not knowing whether 

the North American fungi to which European names have 

been applied really do belong to the same species. Few, if any, 

mycologists have spent enough time on both continents to 

have firsthand comparative knowledge of large numbers of 

their respective fungi and few critical studies have been done to 

evaluate our use of European names. The more comprehensive 

studies that have been done, which unfortunately do not 

include Tricholoma, suggest that many of our species are 

essentially the same as their European counterparts. However, 

for many others, our fungi do not quite fit the European 

concepts and thus probably should be given new names or 

have existing, but unused, North American names resurrected. 

For now, we have no alternative but to continue with our use 

of European Tricholoma names, but with the recognition that 

many might not be good ones for our fungi. 

So, with these caveats, Table 1 presents a preliminary 

listing of North American tricholomas, with emphasis on 

“preliminary.” Inclusion on the list indicates that there is 

good evidence of its status as a species and its existence in 

North America. However, the literature contains mention of 

Fig. 12. Tricholoma magnivelare, the American 

matsutake, popular as an edible in North America and 

collected in large amounts in the West for export to 

Japan, where it has great value and cultural significance. 

Photo by Steve Trudell. 

Fig. 13. Tricholoma portentosum, popular as a lateseason 

edible in eastern North America. Photo by Bill 

Roody. 

many more species than are on this list. Those have not been 

included for one or more of a number of possible reasons: (1) 

the species has not been widely or commonly recognized, and 

its original description is too brief to provide a well defined 

concept that would allow confident identification; (2) although 

the species has been reported as occurring here, those reports 

have been scattered, not thoroughly documented, and often 

involve the application of European names; (3) the species 

is thought to be a new taxon, but has not yet been formally 

described. 

Many of the not-included species were described by 

the American mycologist, William Alphonso Murrill. The 

combination of the brevity of his original descriptions and 

the fact that many of his collections were made in areas, 

particularly Florida, that have been little studied by other 

mycologists makes it very difficult to apply many of his 

names. Many of Charles Horton Peck’s species descriptions 

are similarly brief and difficult to interpret and apply. Keep in 


29

Fig. 14. Tricholoma equestre, popular as an edible in North 

America. However, fatal poisonings caused by this species in 

Europe suggest that considerable caution should be exercised 

when consuming it. Photo by Steve Trudell. 

mind, though, that absence from the list does not necessarily 

mean a species does not occur in North America. Indeed it is 

quite likely that some of them do and, hopefully, future work 

will confirm their presence. 

Efforts are now underway to initiate a long-term 

comprehensive survey of North American macrofungi— 

the North American Mycoflora Project (http://www. 

northamericanmycoflora.org/). The website for the project 

includes links to background documents that explain the 

need for and rationale behind this ambitious undertaking. If 

sufficient funding can be secured and, across the continent, 

mushroom hunters get involved, this would provide a 

great opportunity to develop a better understanding of the 

tricholomas and other mushrooms that inhabit North America 

and help make our lives not only enjoyable, but possible. Please 

take time to learn about the project and then join us! 

References 

Bedry, R., and 11 others. 2001. Wild-mushroom intoxication as 

a cause of rhabdomyolysis. New England Journal of Medicine 

345(11): 798–802. 

Bon, M. 1984. Les Tricholomes de France et d’Europe 

Occidentale. Éditions Lechevalier S.A.R.L., Paris, France. 

Bon, M. 1991. Flore mycologique d’Europe 2: les tricholomes 

et ressemblants. Documents Mycologiques Mémoire Hors 

Série no. 2. 

Deng, H., and Y.-J. Yao. 2005. Tricholoma equestre, the correct 

name for T. flavovirens. Mycotaxon 94: 325–329. 

Fries, E.M. 1821. Systema Mycologicum, Vol. 1. E. Mauritii, 

Greifswald. 

Fries, E.M. 1836–1838. Epicrisis Systematis Mycologici. 

Typographia Academica, Uppsala, Sweden. 

Kauffman, C.H. 1918. The Agaricaceae of Michigan. Biological 

Series 5, Publication 26, Michigan Geological and Biological 

Survey. 

Leonard, L.M. 2000. Is it sinuate or emarginate? McIlvainea 

14(2): 152–156. 

Murrill, W.A. 1914. North American Flora, Volume 10, Part 

1: Agaricales, Agaricaceae (part). The New York Botanical 

Garden. 


Ovrebo, C.L. 1973. Taxonomy of the Genus Tricholoma in 

the Pacific Northwest. Master’s thesis, Department of Botany, 

University of Idaho, Moscow. 

Ovrebo, C.L. 1980. A Taxonomic Study of the Genus 

Tricholoma (Agaricales) in the Great Lakes Region. Ph.D. 

dissertation, Department of Botany, University of Toronto. 

Shanks, K.M. 1994. A Systematic Study of Tricholoma in 

California. M.A. thesis, San Francisco State University, San 

Francisco, California. 

Shanks, K.M. 1997. The Agaricales (Gilled Fungi) of California 

11. Tricholomataceae II. Tricholoma. Mad River Press, Inc., 

Eureka, California. 

Singer, R. 1986. The Agaricales in Modern Taxonomy, 4th ed. 

Koeltz Scientific Books, Koenigstein, Germany. 

Staude, F. 1857. Die Schwämme Mitteldeutschlands, 

insbesondere des Herzogthums Coburg. Coburg, Germany. 

Table 1. Preliminary non-exhaustive list of Tricholoma 

species in North America. See text for discussion. For each 

species, the cap-color group(s) and general distribution in 

North America are indicated. Cap-color groups: Wh (white/ 

silver), Y (yellow), G (gray), B (brown). Distribution: E (east of 

the Rocky Mountains), W (Rocky Mountains and westward). 

T. acre Peck/Hot gray trich (G/E, W) 

T. aestuans (Fries) Gillet (Y/E, W) 

T. albidulum N. Ayala, G. Moreno and Esteve-Raventós 

(Wh/W) 

T. albidum Bon (Wh/E) 

T. apium Jul. Schäffer (Wh, B/E, W) 

T. argenteum Ovrebo (Wh, G/E, W) 

T. arvernense Bon (Y, B/W) 

T. atrodiscum Ovrebo (G/E) 

T. atrosquamosum (Chevalier) Saccardo/Black-scaled trich 

(Wh, G/E, W) 

T. atroviolaceum A.H. Smith (G/W) 

T. aurantio-olivaceum A.H. Smith (Y, B/W) 

T. aurantium (Schaeffer) Ricken/Orange-sheathed trich 

(B/E, W) 

T. caligatum (Viviani) Ricken/Brown matsutake (Wh, B/E, W) 

T. cingulatum (Almfelt) Jacobasch/Belted trich, girdled 

trich (Wh, G/E, W) 

T. colossus (Fries) Quélet/Giant trich (B/E) 

T. davisiae Peck (Y, B/E, W) 

T. dryophilum (Murrill) Murrill (Wh, B/W) 

T. equestre (Linnaeus) P. Kummer/ Man-on-horseback, 

canary trich, yellow trich (Y/E, W) 

T. farinaceum (Murrill) Murrill (Wh/W) 

T. floridanum (Murrill) Murrill (Y/E) 

T. focale (Fries) Ricken (B/E, W) 

T. fracticum (Britzelmayr) Kreisel (B/W) 

T. fulvimarginatum Ovrebo and Halling (B/E) 

T. fulvum (Bulliard) Saccardo/Brown birch trich (B/E, W) 

T. fumosoluteum Peck (Y/E) 

T. grave Peck (B/E) 

T. griseoviolaceum Shanks (Wh, G/W) 

T. hordum (Fries) Quélet (G/E) 

T. huronense A.H. Smith (G/E) 

T. imbricatum (Fries) P. Kummer/ Shingled trich (B/E, W) 

T. inamoenum (Fries) Quélet (Wh/E, W) 

T. insigne Ovrebo (G, B/E) 

T. intermedium Peck (Y/E, W)

T. luteomaculosum A.H. Smith (Y, G/E, W) 

T. magnivelare (Peck) Redhead/ 

Matsutake, pine mushroom, American 

matsutake, white matsutake 

(Wh, B/E, W) 

T. manzanitae Baroni and Ovrebo 

(Wh, B/W) 

T. marquettense Ovrebo (Wh, G/E) 

T. moseri Singer (G, B/W) 

T. muricatum Shanks (B/W) 

T. muskokense nom. prov. (Ovrebo) (B/E) 

T. mutabile Shanks (G/W) 

T. myomyces (Persoon) J.E. Lange (G/E, W) 

T. nigrum Shanks and Ovrebo (G/W) 

T. niveipes Peck (G, B/E) 

T. odorum Peck (Y/E, W) 

T. olivaceobrunneum Ovrebo (G, B/E) 

T. palustre A.H. Smith (Y/E) 

T. pardinum (Persoon) Quélet/Dirty 

trich, poisonous trich (Wh, G/E, W) 

T. pessundatum (Fries) Quélet/Red- 

brown trich (B/E, W) 

T. populinum J.E. Lange/The sandy, 

sand mushroom, poplar trich (B/E, W) 

T. portentosum (Fries) Quélet/Sticky 

gray trich (G/E, W) 

T. pudorinum nom. prov. (Ovrebo) B/E) 

T. pullum Ovrebo / Dusky trich (G/E) 

T. quercetorum nom. prov. (sensu 

Lamoureux) (1) (Y/E) 

T. roseoacerbum A. Riva (B/E) 

T. saponaceum (Fries) P. Kummer/ 

Soap-scented trich (Y, G, B/E, W) 

T. scalpturatum (Fries) Quélet (G, B/E, W) 

T. sejunctum (Sowerby) Quélet (Y/E, W) 

T. serratifolium Peck/Saw-tooth trich 

(Wh, B/E) 

T. silvaticoides (Murrill) Murrill (Wh/E) 

T. squarrulosum Bresadola (G/E, W) 

T. subaureum Ovrebo (Y, B/E) 

T. subluteum Peck (Y/E) 

T. subresplendens (Murrill) Murrill (Wh/E) 

T. sulphurescens Bresadola (Wh, Y/E, W) 

T. sulphureum (Bulliard) P. Kummer/ 

Sulfur trich (Y/E, W) 

T. terreum (Schaeffer) P. Kummer/Earthcolored 

trich, gray trich (G, B/E, W) 

T. transmutans Peck (B/E, W) 

T. tumidum (Persoon) Ricken (Y/W) 

T. ustale (Fries) P. Kummer (B/E, W) 

T. vaccinum (Schaeffer) P. Kummer/ 

Scaly trich, russet-scaly trich (B/E, W) 

T. venenatum G.F. Atkinson 

(Wh, B/E, W) 

T. vernaticum Shanks (Wh, B/W) 

T. virgatum (Fries) P. Kummer/Fibril 

trich, streaked trich (Wh, G/E, W) 

(1) Should this taxon be formally 

described as a new species, it will require 

a different epithet, as ‘quercetorum’ 

already has been used for a species that 

occurs in the Mediterranean region 

(T. quercetorum Contu). 

Watercolor painting by Lily Rankin who writes: "I am 17 years old and live in Copley, Ohio. I attended Spring Garden Waldorf 

School as a child. I have always loved nature. Mushrooms are beautiful and ancient looking. I love to paint and hope to be an 

artist or a medical illustrator." Email: lilyrnkn@gmail.com 


31

The Genus Tricholoma in North America

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