Notes on HEBELOMA in the Pacific Northwest

Prepared for the Pacific Northwest Key Council
By Ian Gibson, South Vancouver Island Mycological Society
Copyright © 2008, 2011, 2019 Pacific Northwest Key Council
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Considerably more field work must be done before a comprehensive key can be written for Hebeloma in the Pacific Northwest. It has been said in jest that there are only four species: veiled Hebeloma, poison pie (Hebeloma crustuliniforme), scaly-stalked Hebeloma (Hebeloma sinapizans group), and sweet-smelling Hebeloma (Hebeloma sacchariolens). That is just to illustrate the difficulty of distinguishing members of the genus which David Arora calls “another faceless and featureless collection of brownish mushrooms”.

By 2019, considerable new research on Hebeloma had been carried out by Henry Beker and his colleagues in Europe and North America including the Pacific Northwest. A European monograph was published in 2016 as the fourteenth volume of the Fungi Europaei series. A North American monograph is planned, which will advance considerably the knowledge of Pacific Northwest species.

A monograph for the veiled Hebelomas was written by A.H. Smith et al. in 1983, The veiled species of Hebeloma in the western United States. The monograph describes more than 90 species of which about a third had collections examined from the Pacific Northwest. Most of the rest were described from Colorado and could occur in the Pacific Northwest. The monograph has now been made available at MykoWeb:
The veiled species of Hebeloma in the western United States and in somewhat less accessible form at the University of Michigan:
The veiled species of Hebeloma in the western United States
The keys it contains should be consulted for detailed work. They have been abstracted below to contain only the species that Smith et al. document from the Pacific Northwest, in this case defined as British Columbia, Washington, Oregon, and Idaho. Identification is based on microscopic features.

Species such as Hebeloma radicosoides and Hebeloma danicum are among the ammonia fungi, studied by Naohika Sagara and found to fruit through the application of ammonia or ammonia-releasing nitrogenous material (such as rotting carcasses) to soil. Because those particular fungi have root-like extensions they have the potential to fruit in response to underground human corpses (“corpse finders"). The occurrence of such fungi in the Pacific Northwest is not well proven.

Descriptions of the veiled species are found in the monograph mentioned above. Hebeloma crustuliniforme [group], Hebeloma sacchariolens [group], and the Hebeloma sinapizans group are well described by Arora (1986). A North American monograph is eagerly awaited.

Hebeloma crustuliniforme group
Hebeloma crustuliniforme group
Kit Scates Barnhart
Hebeloma mesophaeum group
Hebeloma mesophaeum group
Kit Scates Barnhart
Hebeloma sacchariolens group
Hebeloma sacchariolens group
Kit Scates Barnhart
Hebeloma sinapizans group
Hebeloma sinapizans group
Paul Kroeger



1a Veil present, usually fibrillose to cortinate (Subgenus Hebeloma)

1b Veil absent (Subgenus Denudata)

2a Spores in profile view bean-shaped to elliptic or ovate, the apex +/- rounded (Section Mesophaea)

2b Spores +/- inequilateral in profile and narrowed to a blunt apex or apex +/- snoutlike (Section Hebeloma)

3a Spores 10-15 um long or longer (Subsection Subviscidae)

3b Spores 7-10 (11) um long (Subsection Mesophaeae)

4a (2b) Pileus white to pallid or cream color (Subsection Pallidae)

4b Pileus more highly colored when young than in above choice

5a When fresh the odor fragrant to pungent-aromatic (Subsection Praeolidae)

5b Not as above (the odor if present +/- pungent to radishlike)

6a Spores 7-10(11) um long (Subsection Mesosporae)

6b Spores (9) 10-15 um or longer (Subsection Magnisporae)

101a (3a) Odor and taste of radish, lamellae pinkish gray, veil pallid

101b Odor and taste not distinctive

102a Odor and taste farinaceous, interior of stipe bay-red

102b Odor and taste not distinctive, stipe not splitting lengthwise, gregarious not caespitose

201a (3b) Cuticle of pileus an ixotrichodermium rarely collapsing to an ixolattice (study young pilei) (Stirps Pseudostrophosum)

201b Not as above (cuticle rarely an ixolattice in age)

202a Cheilocystidia 40-70 x 7-12 x 2.3-5 um

202b Cheilocystidia 28-43 x 5-7 x 7-9 um

203a (201b) Pileus and/or gills staining dark brown to blackish on some basidiocarps in situ (Stirps Nigromaculatum)

203b Not staining as above

204a Veil whitish (pallid)

204b Veil (or at least outer layer) buff to pale tan

205a (203b) Stipe not darkening at base in age (Stirps Pascuense)

205b Stipe soon darkening in basal area at least (Stirps Mesophaeum)

206a Odor and/or taste raphanoid

206b Odor and/or taste not as above

207a Spores 7-9 x 4.5-5.5 um, veil copious

207b Spores 8-11 x 5-6 um

208a Veil copious and remains long persistent on margin of pileus and/or stipe

208b Veil thin and scarcely leaving a zone of fibrils on the stipe

301a (6a) Stipe not darkening in lower part by maturity

301b Stipe darkening (often slowly) from the base upward

302a Taste bitter-farinaceous; pileus orange-brown when moist

302b Not as above

303a Cheilocystidia 26-33 x 8-12 um

303b Cheilocystidia 40-67 x 4.5-7 um

304a (301b) Spores 7-9 x 4-5 um

304b Spores larger

305a Odor fragrant; cheilocystidia 27-41 x 8-11 um

305b Not as above

306a Cheilocystidia 18-26 x 3-4 um, many of them tibiiform

306b Cheilocystidia not as above (at least wider than 3-4 um)

401a (6b) Stipe not staining or discoloring in the lower portion by late maturity (Stirps Coniferarum)

401b Stipe soon darkening at base or lower portion, then upward

402a Cheilocystidia fusoid-ventricose, the apices subcapitate; odor pungent

402b Not as above

403a Cheilocystidia (some of them) cylindric-subcapitate; pileus slimy viscid

403b Not as above

404a (401b) Spores dextrinoid (medium to dark reddish brown in Melzer’s (Stirps Kuehneri)

404b Spores not dextrinoid, but in a mount a few may be found which become pale to +/- reddish brown in 30 minutes; (dried specimens are most reliable for this test) (Strips Oregonense)

405a Spores 9-12 um long

405b Spores 10-15 um or more long

406a Odor and taste mild or odor weakly pungent

406b Odor and taste raphanoid

407a Veil whitish

407b Veil grayish

408a (404b) Taste and usually the odor of the crushed context raphanoid

408b Not as above (odor +/- pungent in some and in others the taste farinaceous to bitter or at least not raphanoid)

409a Spores 9-12 um long

409b Spores (10) 12-15 um long

410a Spores 9-12 x 5-6.5 um

410b Cheilocystidia not as above (at least wider than 3-4 um)

411a Veil remnants on stem white

411b Veil remnants pale ochraceous

412a (409b) Spores distinctly rough under a high-dry objective

412b Spores appearing smooth under a high-dry objective or a 1.25 NA objective

413a (408b) Stipe staining yellow where injured

413b Stipe not staining yellow where handled

501a (1b) Strong odor sweet and aromatic, like burnt sugar, caramel, fruit candy, or orange blossom

501b Not as above, odor often radish-like

502a Pileus 4-13(20) cm across, typically brown to cinnamon, dark reddish brown, ocher-brown, or pinkish tan, often shaded with gray or overlaid with a pallid sheen toward margin, which is at first minutely cottony; stipe 1-3 cm thick, with distinct pallid to brownish flakes or protruding scales (Arora)

502b Not as above



  1. Arora, David. 1986 Mushrooms Demystified Second Edition. Ten Speed Press, Berkeley.
  2. Beker, Henry J., Ursula Eberhardt, and Jan Vesterholt. 2016. Fungi Europaei Vol. 14, Hebeloma (Fr.) P. Kumm., Edizioni Technografica.
  3. Burdsall Jr., H.H., J.S. MacFall, M.A. Albers. 1986. “Hebeloma arenosa (Agaricales, Cortinariaceae), a new species from lake state nurseries” Mycologia 78(5): 861-865.
  4. Kauffman, C.H., A.H. Smith. 1933. “Agarics collected in the vicinity of Rock River, Michigan in 1929” Pap. Mich. Acad. Sci. Arts Lett. 17.
  5. Sagara, Naohiko. 1984. ‘On "Corpse Finder"’ McIlvainea 6:(2) 7-9.
  6. Sagara, Naohiko, Takashi Yamanaka, Mark Tibbett. 2008. Chapter 4 Soil Fungi Associated with Graves and Latrines: Toward a Forensic Mycology, in ed. Mark Tibbett, David O. Carter, Soil Analysis in Forensic Taphonomy - Chemical and Biological Effects of Buried Human Remains. CRC Press. 364 pages.
  7. Smith, Alexander H. 1938. “New and Unusual Agarics from North America I.” Mycologia 30: 20-41.
  8. Smith, Alexander H. 1949 Mushrooms in Their Natural Habitats. University of Michigan Press, Ann Arbor.
  9. Smith, Alexander H., Smith Helen V., Weber, Nancy S. 1979. How to Know the Gilled Mushrooms. Wm. C. Brown Company, Dubuque, Iowa.
  10. Smith, Alexander H., V.S. Evenson, D.H. Mitchel. 1983. The Veiled Species of Hebeloma in the Western United States. University of Michigan Press, Ann Arbor.
  11. Smith, Alexander H. 1984. “Studies of Species of Hebeloma (Fr.) Kummer from the Great Lakes Region of North America I.” Sydowia 37:271-283.
  12. Trudell, Steve, Joe Ammirati. 2009. Mushrooms of the Pacific Northwest. Timber Press.


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