Hebeloma alpinum (Photo: H. J. Beker)

Taxonomy

Basionym:
Hebeloma crustuliniforme var. alpinum J. Favre, Ergebnisse der Wissenschaftlichen Untersuchungen der des Schweizerischen Nationalparks 5 (Neue Folge) (33): 202 (1955)

Types: SWITZERLAND: Val dal Botsch (approx. 46.65°N, 10.1°E, alt. approx. 2600 m a.s.l.) on calcareous soil in alpine meadow under Dryas octopetala and Salix herbacea, 27 Aug. 1949, J. Favre (Lectotype. herbarium acc. no. G K13674, HJB1000060). Lectotype designated by Vesterholt, Acta Univ. Ups. Symb. Bot. Ups. 30 (3): (1995) page 134.

Homotypic synonyms:

• Hebeloma crustuliniforme f. alpinum (J. Favre) Vassilkov, Macromycetes 1: 59 (1970)
• Hebelomatis alpinum (J. Favre) Locq. 1979, Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]

• arrow_drop_downarrow_drop_upEtymology
  From its habitat in alpine areas from which it was first recorded.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  A typo differt statura minuscula, lamellis latioribus, paucis, stipite semper cavo.

• arrow_drop_downarrow_drop_upEnglish translation
  Differs from the type by the small habit, less numerous, broader lamellae, and always hollow stipe.

Description

Description of Hebeloma alpinum based on 211 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (12) 17–57 (82) mm diameter; shape occasionally convex, broadly umbonate or umbonate, rarely weakly umbonate or strongly umbonate; characters rarely remains of universal veil, spotting, hygrophanous or pubescent; margin characters often smooth, occasionally involute, rarely scalloped, crenulate, eroded, serrate or sulcate; viscosity tacky when moist; colour variation often unicolour, occasionally two color; colour at centre occasionally cream or yellowish brown, rarely dark pinkish buff, brownish olive, sepia, pale yellow, umber, clay-buff, cinnamon, ochraceous, dark greyish buff or pale pinkish buff.

  Lamellae: attachment usually emarginate, rarely adnate or adnexed; maximum depth 2–9 mm; number of complete lamellae 40–72; presence of tears often visible with naked eye, occasionally absent, rarely visible with x10 lens; white fimbriate edge often present, rarely weak or very strong.

  Cortina presence: no.

  Stipe: (10) 15–38 (58) x (2) 4–12 (18) {median} x (2) 4–14 (19) {basal} mm; stipe Q 1.6–10.3; base shape often cylindrical or clavate, rarely tapering, bulbous or sand bulb; floccosity occasionally floccose, pruinose or pruinose at apex, rarely fibrillose, velute, fibrous, floccose at apex or weakly floccose; rooting no; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often stuffed, occasionally hollow, rarely superior wick; stipe flesh discolouring usually no, rarely yes or weak; slenderness measure 1.2–8.6; smell often raphanoid, rarely odourless, cocoa, weakly raphanoid, strongly raphanoid, fruit or soap; taste often mild, occasionally weakly bitter, raphanoid or weakly raphanoid, rarely strongly bitter where recorded.

  Spore deposit colour: often brownish olive, occasionally yellowish brown, rarely clay-buff.

  Exsiccata characters: Not recorded.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, often limoniform; colour in microscope often brown, occasionally yellow brown, rarely brown pale or brown yellow; guttules often yes, occasionally no, rarely weak. papilla usually yes, rarely very strongly; Spore Code: (O1) O2 (O3); P0 P1; D1 D2.

  Basidia: (22) 24–40 (44) x (6) 7–11 μm; ave. Q 3.0–4.3; spore arrangement 4 spored;

  Cheilocystidia: main shape usually clavate-stipitate, often capitate-stipitate, occasionally spathulate-stipitate or clavate-lageniform or clavate-ventricose, rarely gently clavate or clavate; special features observed occasionally apical thickening, septa or many collapsed in exsiccata, rarely conglutinate, sinuate, median thickening, rostrate, yellow contents, bifurcate, clamped septa or geniculate; cheilocystidia ratios: A/M = 1.61–2.75; A/B = 1.52–3.03; B/M = 0.77–1.29.

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

  Ixocutis: epicutis thickness (measured from exsiccata) up to 160 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation often yes, occasionally no; shape of trama elements beneath subcutis often thickly sausage-shaped, ellipsoid or spherical, occasionally angular or cylindrical up to 18 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 120 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma alpinum's preferred habitat appears to be alpine meadow. Where only one possible associate was recorded, the most commonly recorded associate was Salix (58.1%) but Dryas (33.3%), Helianthemum (3.8%) and Betula (2.9%) were also recorded. In these cases the most commonly recorded families were Salicaceae (62.0%) and Rosaceae (30.1%). We have additional records where Populus (9.3%), Picea (8.6%) and Polygonum (3.1%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Salicaceae (71.0%), Rosaceae (40.1%), Pinaceae (9.3%), Polygonaceae (6.2%) and Betulaceae (5.6%) The growth habit of our collections was often scattered, occasionally solitary and rarely gregarious or caespitose.

  According to our current data, the species is found on multiple continents with collections found in Europe (56.7%), Northern America (41.4%) and Temperate Asia (1.9%). 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. tundra (42.1%), temperate conifer forests (29.2%), unknown biome (13.4%) and boreal forests/taiga (11.0%), specifically including the ecoregions: Alps conifer and mixed forests (21.1%), Kalaallit Nunaat Arctic steppe (16.7%), Unknown region (13.4%) and Russian Arctic desert (12.9%). From collector information, it appears collections have been found in the 4.1 Grassland – Tundra (46.1%) and 5.11 Wetlands (inland) – Alpine wetlands (inc. temporary waters from snowmelt) (33.5%) 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 (Svalbard, Norway and Iceland), the Centre (Switzerland, Slovakia and Austria), the Southeast (Italy, Romania and Montenegro) and the Southwest (France and Spain). Specimens have been collected from 42.1°N to 79.0°N.

  Within Northern America we have records from Subarctic America (Greenland, Yukon, Nunavut, Northwest Territories and Alaska), Western Canada (Alberta and Manitoba), Northwestern U.S.A. (Montana) and Eastern Canada (Quebec).

  Within Temperate Asia we have records from Russian Far East (Chukotka) and Siberia (Tyumen).

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma alpinum is not monophyletic, even when concatenating five or six loci,, although in the trees using MCM7, instead of or in addition to Tef1a, H. alpinum is the only non-monophyletic species within the alpinum-complex. Among the loci applied here and by Eberhardt et al. (2015a), not a single one can distinguish H. alpinum on its own. The combination of V6 and V9 is probably the most reliable combination of fewer than five loci for identifying H. alpinum. Hebeloma alpinum V6 sequences cluster with H. geminatum and V9 sequences with H. eburneum. Hebeloma geminatum V9 sequences are much longer than H. alpinum V9, whereas Hebeloma eburneum V6 sequences cluster with H. aanenii. We obtained the ITS1 of the type of H. alpinum.

• arrow_drop_downarrow_drop_upCommentary
  Given the shape of its cheilocystidia, Hebeloma alpinum clearly belongs to H. subsect. Crustuliniformia and most likely corresponds to ICG4 of Aanen & Kuyper (1999). Within this section, it certainly appears to be confined to alpine or arctic habitats and can be readily separated from other alpine/arctic species in this section based on the number of lamellae, usually between 40 and 60 on average, and the size of the spores, on average at least 11 μm long and more than 6 μm wide. It also has quite a squat, robust stature. As discussed in Eberhardt et al. (2015a), we have examined material of Hebeloma bellotianum, which was recorded in 1876 from Bellot Island in Canada by Capt. Feilden and described by M.J. Berkeley as Agaricus (Naucoria) bellotianus in 1878. Hebeloma bellotianum has cheilocystidia that clearly place it in H. subsect. Crustuliniformia and, given the habitat at more then 81 deg N, it falls into the arctic/alpine group from this subsection. The number of lamellae (estimated from the exsiccata) and spore size would mean that it would key out, among known species from this subsection, as H. alpinum, to which it is certainly closely related and were it not for the very large spores we would be confident this was the same species. However, the spores of H. bellotianum measured, on average, 14.7 × 7.1 μm, while the largest average spore size we have measured for H. alpinum (across 72 collections) is 13.7 μm long (and 7.7 μm wide). We have not been able to obtain any molecular data from this collection and cannot rule out that this may be a species from H. subsect. Crustuliniformia that we have not yet encountered. Thus, at this point, we hesitate to synonymize these species and await further evidence one way or the other. Hebeloma alpinum is the most common Hebeloma species we have collected in arctic/alpine areas. It can usually be determined, with reasonably high confidence, in the field.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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