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, 2023 Pacific Northwest Key Council
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INTRODUCTION

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 Kit Scates Barnhart

Hebeloma mesophaeum group Kit Scates Barnhart

Hebeloma sacchariolens group Kit Scates Barnhart

Hebeloma sinapizans group Paul Kroeger

KEY TO SPECIES

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

................................................................................2

1b Veil absent (Subgenus Denudata)

................................................................................501

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

................................................................................3

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

................................................................................4

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

................................................................................101

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

................................................................................201

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

................................................................................Hebeloma salmonense (may be a synonym of Hebeloma velutipes)

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

................................................................................5

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

................................................................................Hebeloma praeolidum

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

................................................................................6

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

................................................................................301

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

................................................................................401

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

................................................................................Hebeloma vinaceogriseum (synonym of H. mesophaeum var. obscurum in Eberhardt et al. 2022)

101b Odor and taste not distinctive

................................................................................102

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

................................................................................Hebeloma sterlingii (synonymized with Hebeloma excedens in Eberhardt et al. (2022)

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

................................................................................Hebeloma ollaliense

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

................................................................................202

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

................................................................................203

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

................................................................................Hebeloma pseudostrophosum

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

................................................................................Hebeloma alpinicola (may be same sp. as H. perigoense and H. nigromaculatum)

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

................................................................................204

203b Not staining as above

................................................................................205

204a Veil whitish (pallid)

................................................................................Hebeloma nigromaculatum (may be same species as H. alpinicola and H. perigoense)

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

................................................................................Hebeloma angelesiense (H. pseudostrophosum may be the same species)

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

................................................................................Hebeloma perigoense (may be same species as H. alpinicola and H. nigromaculatum)

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

................................................................................206

206a Odor and/or taste raphanoid

................................................................................207

206b Odor and/or taste not as above

................................................................................Hebeloma mesophaeum

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

................................................................................Hebeloma strophosum var. strophosum

207b Spores 8-11 x 5-6 um

................................................................................208

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

................................................................................Hebeloma strophosum var. occidentale

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

................................................................................Hebeloma mesophaeum

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

................................................................................302

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

................................................................................304

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

................................................................................Hebeloma aurantiellum

302b Not as above

................................................................................303

303a Cheilocystidia 26-33 x 8-12 um

................................................................................Hebeloma immutabile

303b Cheilocystidia 40-67 x 4.5-7 um

................................................................................See Hebeloma fastibile

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

................................................................................Hebeloma olympianum

304b Spores larger

................................................................................305

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

................................................................................Hebeloma pinetorum

305b Not as above

................................................................................306

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

................................................................................Hebeloma subhepaticum

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

................................................................................Hebeloma parcivelum

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

................................................................................402

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

................................................................................404

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

................................................................................Hebeloma pungens

402b Not as above

................................................................................403

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

................................................................................Hebeloma kelloggense

403b Not as above

................................................................................Hebeloma pseudofastibile

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

................................................................................405

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)

................................................................................408

405a Spores 9-12 um long

................................................................................406

405b Spores 10-15 um or more long

................................................................................Hebeloma marginatulum

406a Odor and taste mild or odor weakly pungent

................................................................................407

406b Odor and taste raphanoid

................................................................................Hebeloma pseudofastibile

407a Veil whitish

................................................................................Hebeloma occidentale (synonymized with H. palustre in Eberhardt et al. 2022)

407b Veil grayish

................................................................................Hebeloma obscurum (synonymized with H. palustre in Eberhardt et al. 2022)

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

................................................................................409

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

................................................................................413

409a Spores 9-12 um long

................................................................................410

409b Spores (10) 12-15 um long

................................................................................412

410a Spores 9-12 x 5-6.5 um

................................................................................Hebeloma fastibile (may be nomen dubium et confusum)

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

................................................................................411

411a Veil remnants on stem white

................................................................................Hebeloma latisporum

411b Veil remnants pale ochraceous

................................................................................Hebeloma idahoense (synonymized with H. palustre in Eberhardt et al. 2022)

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

................................................................................Hebeloma stanleyense (synonymized with H. palustre in Eberhardt et al. 2022)

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

................................................................................Hebeloma oregonense

413a (408b) Stipe staining yellow where injured

................................................................................Hebeloma lutescentipes (synonymized with H. palustre in Eberhardt et al. 2022)

413b Stipe not staining yellow where handled

................................................................................Hebeloma oregonense

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

................................................................................Hebeloma sacchariolens

501b Not as above, odor often radish-like

................................................................................502

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)

................................................................................Hebeloma sinapizans group

502b Not as above

................................................................................Other groups including Section Velutipes (H. velutipes etc.) and Section Denudata (H. crustuliniforme group, H. cavipes, ­­H. hiemale, etc.)

REFERENCES

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. Eberhardt, U., Nicole Schütz, Peter Bartlett, & Henry J. Beker. 2022. "96 North American taxa sorted – Peck’s Hebeloma revisited." Mycologia 114(2):337-387.
5. 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.
6. Sagara, Naohiko. 1984. ‘On "Corpse Finder"’ McIlvainea 6:(2) 7-9.
7. 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.
8. Smith, Alexander H. 1938. “New and Unusual Agarics from North America I.” Mycologia 30: 20-41.
9. Smith, Alexander H. 1949 Mushrooms in Their Natural Habitats. University of Michigan Press, Ann Arbor.
10. Smith, Alexander H., Smith Helen V., Weber, Nancy S. 1979. How to Know the Gilled Mushrooms. Wm. C. Brown Company, Dubuque, Iowa.
11. 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.
12. Smith, Alexander H. 1984. “Studies of Species of Hebeloma (Fr.) Kummer from the Great Lakes Region of North America I.” Sydowia 37:271-283.
13. Trudell, Steve, Joe Ammirati. 2009. Mushrooms of the Pacific Northwest. Timber Press.

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