Hebeloma helodes (Photo: H. J. Beker)

Taxonomy

Types: SWITZERLAND: Vaud, Tourbiere du sentier, Vallee de Joux, Jura vaudois (approx. 46.65°N, 6.25°E, alt. approx. 1180 m a.s.l.) on boggy soil in bog pathside ditch under Betula sp. and Pinus sp., 30 Aug. 1939, J. Favre (Lectotype. herbarium acc. no. G K9139, G 00053920, HJB1000054). Lectotype designated by Gröger, Mykol. Mitteilungsbl. 30 (2): (1987) page 46.

Heterotypic synonyms:

• Hebeloma crustuliniforme var. minus (Cooke) Massee [as "minor"], British Fungus-Flora. A Classified Text-Book of Mycology 2: 176 (1893)
• Hebeloma kemptoniae A.H. Sm., V.S. Evenson & Mitchel [as "kemptonae"], The Veiled Species of Hebeloma in the Western United States: 112 (1983)
• Agaricus crustuliniformis var. minor (Cooke) Cooke [as "Agaricus (Hebeloma) crustuliniformis var. minor"] [“1883-1891”], Handbook of British Fungi Edn. 2: 164 (1886)
• Agaricus crustuliniformis f. minor Cooke [as "Agaricus (Hebeloma) crustuliniformis f. minor"] [“1881-1891”], Illustr. Br. Fungi: 414 (1884)

• arrow_drop_downarrow_drop_upEtymology
  From helodes– (Greek) frequenting marshes. Favre collected this species in ‘peaty places’.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileo ad usque 3 cm lato, convexo, dein expanso, demum depresso, umbone nullo vel subnullo, viscoso, argillaceo sed centro pallide fuligineo infecto, margine sulcato et sutile araneoso-floccoso. Lamellis angustis, usque ad 2,8 mm latis tenuibus, sat confertis (33–41), albido-alutaceis, dein alutaceo-fuscis, plorantibus. Stipte subaequo, usque ad 6 cm x 3,5–5 mm, fere ubique pruinoso-flocculoso, fusco-albido. Carne albida, in stipite pallide fusca, non amara. Sporis amygdaloidibus (8–11 x 5,5–5 μm). Pilis lamellarum marginis longis, gracilis, sursum capitatis. In turfosis paludibus.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus up to 3 cm broad, convex then expanding, finally depressed, without or with weak umbo, viscous, clay-coloured but centre tinged pale reddish brown, with sulcate and finely cobwebby-floccose margin. Lamellae narrow, up to 2.8 mm broad, thin, rather crowded (33–41), white-yellowish, then yellowish brown, exuding droplets. Stipe subequal, up to 6 cm × 3.5–5 mm, pruinose-flocculose all over, brownish white. Context white, in stipe pale brown, not bitter. Spores amygdaloid (8–11 × 5–5.5 μm). Marginal hairs long, slender, capitate at apex. In peaty places.

Description

Description of Hebeloma helodes based on 67 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (13) 16–39 (50) mm diameter; shape often convex, occasionally strongly umbonate, rarely umbonate, broadly umbonate or umbilicate; characters occasionally tomentose, rarely hygrophanous, remains of universal veil or pubescent; margin characters occasionally involute or smooth, rarely crenulate, sulcate, reflexed or serrate; viscosity tacky when moist; colour variation often two color, occasionally unicolour; colour at centre occasionally orange-brown, pinkish buff or ochraceous, rarely yellowish brown or greyish brown.

  Lamellae: attachment usually emarginate, rarely adnate or adnexed; maximum depth 3–6 mm; number of complete lamellae 32–54; presence of tears often visible with naked eye, rarely absent or visible with x10 lens; white fimbriate edge often present, occasionally very strong, rarely weak.

  Cortina presence: usually no, rarely yes.

  Stipe: (15) 21–64 (80) x 2–5 (8) {median} x (2) 3–7 (8) {basal} mm; stipe Q 3.3–20.0; base shape often cylindrical, occasionally clavate, rarely bulbous; floccosity occasionally floccose, weakly floccose or pruinose, rarely fibrillose, floccose at apex or none; rooting no; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often hollow, occasionally stuffed; stipe flesh discolouring often no, occasionally yes, rarely weak; slenderness measure 5.4–49.1; smell often raphanoid, occasionally weakly raphanoid, rarely odourless; taste occasionally weakly bitter or mild, rarely none, raphanoid or weakly raphanoid where recorded.

  Spore deposit colour: often yellowish brown or brownish olive.

  Exsiccata characters: often pale, rarely fragile.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid; colour in microscope occasionally yellow, brown, very pale or yellow brown; guttules variable. papilla usually no, rarely weak; Spore Code: O2 O3; P0 P1 (P2); D0 D1.

  Basidia: 20–30 (31) x 5–8 (9) μm; ave. Q 2.8–4.2; spore arrangement 4 spored;

  Cheilocystidia: main shape usually clavate-stipitate, often capitate-stipitate, rarely clavate-lageniform or clavate-ventricose, capitate, spathulate-stipitate or subcapitate; special features observed often apical thickening, rarely many collapsed in exsiccata, septa, subcapitate, median thickening, large, spathulate or thick content in neck; cheilocystidia ratios: A/M = 1.90–2.86; A/B = 2.02–3.38; B/M = 0.76–1.17.

  Pleurocystidia: usually none seen, rarely only close to lamella edge.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 135 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation often yes, occasionally no; shape of trama elements beneath subcutis thickly sausage-shaped, often ellipsoid, occasionally cylindrical or isodiametric up to 15 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma helodes's preferred habitat appears to be deciduous woodland with grassy soil. Where only one possible associate was recorded, the most commonly recorded associate was Salix (53.6%) but Alnus (17.9%), Betula (14.3%), Fagus (3.6%), Pinus (3.6%), Populus (3.6%) and Picea (3.6%) were also recorded. In these cases the most commonly recorded families were Salicaceae (51.6%), Betulaceae (32.3%) and Pinaceae (12.9%). We have additional records where Corylus (6.8%), Abies (6.8%) and Quercus (2.3%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Salicaceae (52.3%), Betulaceae (43.2%), Pinaceae (29.6%) and Fagaceae (6.8%) The growth habit of our collections was often scattered, occasionally solitary and rarely gregarious or caespitose.

  According to our current collections, the species is predominantly found in Europe (80.3%) but also found in Northern America (19.7%). On these continents, collections has been found in the WWF biomes The World Wildlife Fund (WWF) have divided the world into 867 terrestrial ecoregions. The ecoregion here is estimated by mapping from the GPS coordinates of the collection using data made available by Dinerstein et al (2017). Use this webtool to explore the ecoregions visually or see a full list of current ecoregions on Wikipedia. temperate broadleaf & mixed forests (57.6%), boreal forests/taiga (15.3%) and temperate conifer forests (11.9%), specifically including the ecoregions: Western European broadleaf forests (15.3%), Celtic broadleaf forests (11.9%) and European Atlantic mixed forests (10.2%). From collector information, it appears collections have been found only in the 1.4 Forest – Temperate IUCN habitat We map from the collector's description of the habitat to the International Union for Conservation of Nature (IUCN)'s definition using a standardised set of rules. Please see this page for a full list of IUCN habitats..

  Within Europe we have records from the North (Norway, England, Scotland, Wales, Isle Of Man, Faroe Islands, Finland and Denmark), the Centre (Germany, Netherlands, Belgium, Poland and Switzerland) and the Southwest (France and Italy). Specimens have been collected from 43.0°N to 62.0°N.

  Within Northern America we have records from Subarctic America (Greenland and Alaska), Northwestern U.S.A. (Oregon and Washington), Eastern Canada (Quebec) and Western Canada (British Columbia).

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma helodes is monophyletic. The species is very closely related to H. aurantioumbrinum and can only be separated from this taxon using RPB2 or MCM7 (Eberhardt et al. 2015a), but not by ITS.

• arrow_drop_downarrow_drop_upCommentary
  Given the shape of its cheilocystidia, Hebeloma helodes clearly belongs to H. subsect. Crustuliniformia. This species most likely corresponds to ICG12 of Aanen & Kuyper (1999). We have no confirmed records of this taxon in arctic or alpine habitats, although it appears closely related to H. aurantioumbrinum which does exist in these habitats. It can be readily distinguished from the other members of this subsection that grow in lowland areas based on the number of lamellae, between 30 and 60, the small spore length, less than 11 μm, the large average width of the cheilocystidium apex, greater than 8 μm, and the regular apical thickening of the cheilocystidium wall. It has probably often been confused with H. pusillum, which is also a small Hebeloma, but H. pusillum is confined to Salix, has less than 30 full length lamellae, has a more fragile stature and usually a rather darker centre to the pileus. It also has, on average, significantly longer spores. Hebeloma luteicystidiatum also has fewer lamellae and longer spores and is usually somewhat smaller. Hebeloma aurantioumbrinum, which is closely related to H. helodes, is rarely found in non alpine/arctic habitats, but in any case can be distinguished microscopically because its cheilocystidia walls very rarely have any sign of apical thickening. It also usually has a much more brightly coloured pileus. In many ways, Hebeloma helodes does resemble a small member of the crustuliniforme-complex and we have no doubt that Cooke’s Agaricus crustuliniformis var. minor is this species. Hebeloma helodes was first described by J. Favre in 1948, but no material was selected as holotype. In 1987, F. Gröger selected Favre’s original material, on which Favre had based his description, as lectotype.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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