Hebeloma monticola (Photo: J. Vesterholt)

Taxonomy

• arrow_drop_downarrow_drop_upNomenclatural notes
  Vesterholt may have intended this as replacement name for H. remyi, which he believed to be invalid. Given that H. remyi is now considered valid this name would have been superfluous and, hence, illegitimate. However, it was properly diagnosed and a type was selected, so this name is valid.

Types: SWEDEN: Vattjom (approx. 62.36°N, 17.04°E, alt. approx. 95 m a.s.l.) under Betula sp. and Salix sp., 7 Sep. 1986, S. Muskos (6133), det: J. Vesterholt (Holotype. herbarium acc. no. C C-F-84155, HJB1000019).

• arrow_drop_downarrow_drop_upEtymology
  From monticola– a dweller on mountains, to describe the habitat. The species is in fact boreal rather than alpine.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileus primum hemisphaericus, deinde minus convexus vel expansus, 21–40 mm latus, supra viscidus vel paene siccus, in medio primum fuscus, provecta aetate pallescens, ad marginem laetior. Velum universale et velum partiale presentiae. Lamella emarginatae. Stipe 25–80 x 2–6 mm magnus, cylindricus vel ad basem versus clavatim dilatatus. Sporae amygdaloides, 10.5–12.5 x 6–7 μm magnae, asperulae, dextrinoides; cheilocystidia cylindrica, prope bases dilatata. Habitat sub Salice et Betula.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus hemispherical at first, then weakly convex to expanded, 21–40 mm broad, surface viscid or almost dry, centre sordid brown at first, fading with age, paler at margin. Velum universale and partiale present. Lamellae emarginate. Stipe 25–80 × 2–6 mm, cylindrical or towards base broadened, clavate. Spores amygdaloid, 10.5–12.5 × 6–7 μm, roughened, dextrinoid; cheilocystidia cylindrical, broadened towards base. Under Salix and Betula.

Description

Description of Hebeloma monticola based on 42 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (11) 15–49 (60) mm diameter; shape usually convex, often umbonate, occasionally weakly umbonate; characters remains of universal veil, occasionally hygrophanous; margin characters usually involute, often smooth, occasionally wavy; viscosity tacky when moist; colour variation often two color, occasionally unicolour; colour at centre orange-brown.

  Lamellae: attachment usually emarginate, occasionally adnate or decurrent tooth; maximum depth not recorded; number of complete lamellae 50–64; presence of tears usually absent, rarely visible with x10 lens; white fimbriate edge often present, occasionally weak, rarely absent.

  Cortina presence: yes.

  Stipe: (25) 50–92 (112) x (2) 4–9 (12) {median} x (3) 4–12 (16) {basal} mm; stipe Q 6.5–19.8; base shape often cylindrical or clavate; floccosity fibrillose, usually pruinose at apex, occasionally floccose at apex; rooting no; thick rhizoids at base absent;

  Context: Texture firm; stipe interior Not recorded; stipe flesh discolouring variable occasionally weak; slenderness measure 10.9–59.5; smell occasionally raphanoid, odourless or strongly raphanoid, rarely earthy, farinaceous or tea; taste occasionally weakly bitter, mild, raphanoid, hot or none where recorded.

  Spore deposit colour: Not recorded.

  Exsiccata characters: occasionally pileus blackening.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, often limoniform, rarely ovoid; colour in microscope usually yellow brown, rarely brown; guttules variable. papilla often yes, occasionally no, rarely weak; Spore Code: O2 O3; P0 P1; D2 D3.

  Basidia: (21) 24–34 x 6–10 μm; ave. Q 2.6–3.9; spore arrangement 4 spored;

  Cheilocystidia: main shape ventricose, usually lageniform, rarely cylindrical; special features observed often basal thickening, occasionally septa or irregular, rarely geniculate, many collapsed in exsiccata, median thickening or uniform; cheilocystidia ratios: A/M = 1.01–1.25; A/B = 0.50–0.89; B/M = 1.42–2.21.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 160 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation variable; shape of trama elements beneath subcutis occasionally cylindrical, polygonal, thickly sausage-shaped or thinly sausage-shaped up to 14 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 115 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma monticola's preferred habitat appears to be boreal with soil, boggy soil or deeply-mossy soil. Where only one possible associate was recorded, the most commonly recorded associate was Picea (71.4%) but Betula (14.3%) and Fagus (14.3%) were also recorded. In these cases the most commonly recorded families were Pinaceae (71.4%), Betulaceae (14.3%) and Fagaceae (14.3%). We have additional records where Salix (26.9%), Populus (26.9%), Alnus (23.1%), Tsuga (7.7%) and Abies (3.9%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Pinaceae (65.4%), Betulaceae (57.7%) and Salicaceae (53.9%) The growth habit of our collections was often scattered or solitary and occasionally gregarious.

  According to our current data, the species is found on multiple continents with collections found in Europe (62.2%) and Northern America (37.8%). 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. boreal forests/taiga (51.2%) and tundra (22.0%), specifically including the ecoregions: Scandinavian and Russian taiga (31.7%) and Pacific Coastal Mountain icefields and tundra (14.6%). From collector information, it appears collections have been found in the 1.1 Forest – Boreal (61.9%) and 1.4 Forest – Temperate (23.8%) 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 (Norway, Sweden and Finland) and the Centre (Sweden). Specimens have been collected from 59.2°N to 69.6°N.

  Within Northern America we have records from Subarctic America (Alaska), Eastern Canada (Quebec and Newfoundland and Labrador), Western Canada (British Columbia) and Southwestern U.S.A. (Arizona).

• arrow_drop_downarrow_drop_upMolecular results
  With only four collections and only a single sequence from a protein-coding locus it is difficult to assess the molecular delimitation of H. monticola. The species is supported by 91% bootstrap in the five-locus tree, but with the small number of sequences in total (three ITS, two V6 and V9 sequences, and one of each of Tef1a and RPB2), it is difficult to assess the reliability of this result. Neither the three ITS sequences, nor the two V6 and V9 sequences are monophyletic in single ocus results. Using molecular identification tools, the species could be mistaken for H. clavulipes, H. hygrophilum, H. nigellum, H. oreophilum or H. spetsbergense.

• arrow_drop_downarrow_drop_upCommentary
  With the persistent presence of a cortina and the lageniform or ventricose cheilocystidia, this taxon clearly belongs in H. section Hebeloma. Within this section, it can be differentiated on the basis of the amygdaloid and limoniform spores, distinctly to rather strongly dextrinoid, the number of lamellae always at least 40 and the boreal, rather than arctic or alpine, habitat. The closest taxa are H. oreophilum, which only occurs in arctic or alpine habitats, H. sordescens that can occur in similar habitats, but has a very narrow cheilocystidium apex and for which the exsiccata almost always strongly discolours and H. clavulipes. Distinguishing between H. monticola and H. clavulipes is rather more problematic. Based on our database collections, H. monticola does have more crowded lamellae and it is on this basis that we key them out. Equally importantly, the spore shape is somewhat different: Hebeloma clavulipes has a distinct papilla and the spores often look limoniform, while H. monticola spores rarely have a distinct papilla and the spores often have a more ovoid look to them, more closely resembling H. nigellum. Also, the habitat for H. monticola does appear rather narrow (all our collections being from Scandinavia with latitude greater than 60 deg N), although H. clavulipes does occur in these regions. From a molecular viewpoint these two species also appear very closely related, however, there are distinct molecular differences. Putting all this together is sufficient to stop us synonymizing these two taxa. Perhaps with further collections and more molecular loci, we will be able to make a more certain differentiation. The photograph of the holotype is taken from the original publication which was in black and white; the original watercolour appears to be lost.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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