Hebeloma vaccinum (Photo: H. J. Beker)

Taxonomy

Types: FRANCE: Oise, La-Neuville-en-Hez (Oise) (approx. 49.4°N, 2.32°E, alt. approx. 100 m a.s.l.) on boggy, grassy soil in lakeside verge under Populus sp., 1961, H. Mesplede, H. Romagnesi (HR-R61-159), det: H. Romagnesi (R61-159) (Holotype. herbarium acc. no. PC0090761, HJB1000029; Isotype. herbarium acc. no. TENN-F-037574, HJB1000561).

Heterotypic synonyms:

• Hebeloma alvarense Vesterh. & Vauras, Karstenia 44: 57 (2004)
• Hebeloma alvarense var. hinnuleum Vesterh., Fungi N. Eur. 3. 3: 96 (2005)

Homotypic synonyms:

• Hebelomatis vaccinum (Romagn.) Locq., Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]

• arrow_drop_downarrow_drop_upEtymology
  From vaccinus– dun (dull greyish brown) in colour.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileo 1,8–3 cm, carnoso, tenero, convexo, deinde applanato. Obtuso vel vix gibboso, margine involuta et pallida, dein patente, vivide e rufo-ochraceo brunneo, paulum sicco pallescente, lucido, viscosissimo. Stipite 2,8–5 cm x 3,5–6 cm, aequali, fere candido, vel parum colorato, striato, subtiliter ad apicem pruinoso. Cortina nulla. Carne fragili, candida, odore raporum ac herbarum, sapore amaro. Lamelles parum stipatis, sinuates-liberis pallidissime ex ochraceis brunneis, dein brunneolis, acie pruinosa ac alba, tenuiter plorantibus. Sporis in cumulo brunneis, amygdaliformibus, 11–13 x 6–7,7 μm, vivide flavis, manifestissime verrucosis, perispora distincta. Pillis acierum ciliformibus vel sublageniformibus, saepe paulum clavatis, 43–68 x 5,5–10 μm. Subcute pseudoparenchymatica manifestissima, intense colorata, sicut epicutis, cujus hyphae graciles quoque sont flavae, summa parte interdum excepta. Prope stagnum, cum populis proximis.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus 1.8–3 cm, fleshy, weak, convex then flattened, blunt or hardly umbonate, with pale involute then expanded margin, vivid ochre reddish then brown, weakly discolouring on drying, shining, very viscid. Stipe 2.8–5 cm × 3.5–6 cm, equal, first white then a little coloured, striate, delicately pruinose at apex. Cortina absent. Context fragile, white, smell raphanoid or herbaceous, taste bitter. Lamellae more or less distant, sinuate-free, pale ochre-brown then brownish with pruinose, white edge. Spore print brown; spores amygdaloid, 11–13 × 6–7.7 μm, vividly yellow, distinctly verrucose, with distinct perispore. Marginal hairs hair-shaped to sublageniform, often weakly clavate, 43–68 × 5.5–10 μm. Subcutis distinctly pseudoparenchymatous, intensely pigmented, like the epicutis, of which the slender hyphae also are yellow, except for the upper part. Near stagnant water, close to Populus.

Description

Description of Hebeloma vaccinum based on 129 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (9) 15–46 (64) mm diameter; shape usually convex, rarely umbonate, strongly umbonate or broadly umbonate; characters rarely spotting; margin characters occasionally smooth, scalloped, crenulate or involute, rarely sulcate; viscosity tacky when moist; colour variation often two color, occasionally unicolour; colour at centre occasionally umber, dark brick or cinnamon, rarely clay-buff, yellowish brown, dark fawn, sepia or brick.

  Lamellae: attachment usually emarginate, rarely adnate, adnexed, decurrent tooth or free; maximum depth 2–7 mm; number of complete lamellae 30–70; presence of tears often visible with naked eye, occasionally absent or visible with x10 lens; white fimbriate edge often present, occasionally weak, rarely very strong.

  Cortina presence: no.

  Stipe: (9) 19–50 (67) x (2) 3–7 (13) {median} x (2) 3–9 (13) {basal} mm; stipe Q 2.2–13.3; base shape often cylindrical, occasionally clavate, rarely sand bulb, tapering, bulbous or subbulbous; floccosity occasionally pruinose, floccose or pruinose at apex, rarely fibrillose, weakly floccose, fibrous, floccose at apex or velute; rooting usually no, rarely yes; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often hollow, occasionally stuffed, rarely superior wick; stipe flesh discolouring often no, occasionally yes, rarely weak; slenderness measure 2.4–23.6; smell often raphanoid, occasionally cocoa or odourless, rarely weakly raphanoid, earthy or strongly raphanoid; taste often mild, occasionally weakly bitter or raphanoid, rarely bitter or weakly raphanoid where recorded.

  Spore deposit colour: occasionally brownish olive, umber or sepia.

  Exsiccata characters: rarely shiny or lamellae blackening.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, often limoniform, rarely fusoid; colour in microscope often brown, occasionally yellow brown, rarely yellow; guttules often yes, occasionally no, rarely weak. papilla often yes, occasionally very strongly, rarely weak; Spore Code: O3; P1 P2; (D2) D3.

  Basidia: 25–39 (42) x 6–10 (11) μm; ave. Q 3.0–4.6; spore arrangement 4 spored;

  Cheilocystidia: main shape usually clavate-lageniform or clavate-ventricose, occasionally clavate-stipitate, rarely capitate, lageniform, capitate-stipitate, clavate, ventricose, gently clavate or tapering; special features observed occasionally median thickening, septa or apical thickening, rarely geniculate, many collapsed in exsiccata, short, sinuate, clamped septa, rostrate or subcapitate; cheilocystidia ratios: A/M = 1.43–2.54; A/B = 0.84–1.90; B/M = 1.28–1.92.

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

  Ixocutis: epicutis thickness (measured from exsiccata) up to 125 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation usually yes, rarely no; shape of trama elements beneath subcutis occasionally angular, polygonal, thickly sausage-shaped or thinly sausage-shaped, rarely ellipsoid, isodiametric or spherical up to 15 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 100 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma vaccinum's preferred habitat appears to be coastal dune with sandy soil. Where only one possible associate was recorded, the most commonly recorded associate was Salix (78.3%) but Populus (12.0%), Dryas (5.4%), Pinus (3.3%) and Fagus (1.1%) were also recorded. In these cases the most commonly recorded family was Salicaceae (91.0%). We have additional records where Betula (5.7%) and Helianthemum (1.9%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Salicaceae (89.6%), Pinaceae (6.6%), Betulaceae (6.6%) and Rosaceae (6.6%) The growth habit of our collections was often scattered and rarely gregarious, solitary or caespitose.

  According to our current collections, the species is predominantly found in Europe (83.2%) but also found in Northern America (16.8%). 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 (62.2%), tundra (13.4%) and unknown biome (12.6%), specifically including the ecoregions: European Atlantic mixed forests (32.8%), Unknown region (12.6%), Celtic broadleaf forests (11.8%) and Kalaallit Nunaat Arctic steppe (11.8%). From collector information, it appears collections have been found in the 13.3 Coastal Sand Dunes (52.9%), 1.4 Forest – Temperate (11.8%) and 4.1 Grassland – Tundra (11.8%) IUCN habitats 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 (Denmark, Wales, England, Isle Of Man, Scotland, Norway, Iceland and Sweden), the Centre (Belgium, Netherlands, Germany, Poland, Switzerland and Slovakia), the Southwest (France, Italy and Channel Islands), the Southeast (Italy and North Macedonia) and Eastern Europe (Estonia and Yaroslavl). Specimens have been collected from 39.2°N to 65.5°N.

  Within Northern America we have records from Subarctic America (Greenland, Nunavut and Alaska), Northwestern U.S.A. (Oregon and Colorado) and Eastern Canada (Ontario).

• arrow_drop_downarrow_drop_upMolecular results
  See under H. cavipes. Hebeloma vaccinum does not even form a monophyletic group with five or six loci concatenated, but it is not mixed with any other species. The separation of H. cavipes and H. vaccinum in our results is largely due to RPB2 data; we obtained too few Tef1a sequences to be sure whether this locus separates the two species. We have obtained molecular data (but unfortunately not of RPB2 or Tef1a) supporting that H. alvarense and H. alvarense var. hinnuleum are included in the ITS clade with H. cavipes and H. vaccinum. In the case of the isotype of H. vaccinum var. cephalotum, ITS data clearly shows that it is not H. pusillum like the holotype.

• arrow_drop_downarrow_drop_upCommentary
  Given the shape of its cheilocystidia (primarily clavate-lageniform) and the spores mainly O3 and D3 and usually with a strongly loosening perispore, Hebeloma vaccinum belongs to H. sect. Denudata subsect. Clepsydroida. This species most likely corresponds to ICG15 of Aanen & Kuyper (1999). The spore width, on average, greater than 6.5 μm places this species in a small group with H. ammophilum and H. matritense. It is separated from H. matritense on both the number of lamellae (at most 65) and the average spore length (at least 12.5 μm). This taxon is morphologically and ecologically closely related to H. ammophilum. Both can be found in wet sandy soil with Salicaceae. However, H. ammophilum is normally of a larger stature and microscopically it has cheilocystidia more swollen at the apex (average greater than 8 μm). Also, we have no records of H. ammophilum from dunes or in arctic or alpine habitats. Molecularly, Hebeloma vaccinum is very closely related to H. cavipes. However, the two are easily separated on a variety of microscopic characters and also H. cavipes is usually a more slender species with a wide variety of mycorrhizal associates. Both molecularly and microscopically (and largely macroscopically), both H. alvarense and H. alvarense var. hinnuleum resemble H. vaccinum. Macroscopically, there are some small differences (e.g. H. alvarense var. hinnuleum has its number of full length lamellae at the top end of the range for H. vaccinum), but we feel the differences are insufficient evidence to warrant different species. Therefore we have synonymized these taxa. We have found that the isotype of Hebeloma vaccinum var. cephalotum is conspecific with H. vaccinum and we have used this collection within our cited collections. However the holotype of H. vaccinum var. cephalotum is conspecific with H. pusillum and has been synonymized with that taxon. Hebeloma vaccinum var. cremeopallidum is synonymous with H. fusisporum, as the authors of the species realized themselves (Esteve-Raventos & Heykoop 1998). Collections HJB11012 and HJB11578 are two white-spored (“Hebelomina”) collections of H. vaccinum. They were collected in almost exactly the same location but in two consecutive years (2005 and 2006). While we do not know, whether the same mycelium was sampled or different individuals, and then possibly off-spring of the originally sampled individual (mycelium), it appears unlikely that the lack of spore colour was caused by the physical environment. In both cases we were unable to get a spore print from the basidiomes.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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