Hebeloma lutense (Photo: J. Vesterholt)

Taxonomy

Types: FRANCE: Yvelines, Foret de Rambouillet (S.-et-O.), etang de la Tour. (approx. 48.6°N, 1.7°E, alt. approx. 135 m a.s.l.) on silty soil in woodland lakeside under Betula sp. and Salix sp., 11 Oct. 1959, H. Romagnesi (R59.232) (Holotype. herbarium acc. no. PC0086210, HJB1000253; Isotype. herbarium acc. no. L 0054088, HJB1000011).

• arrow_drop_downarrow_drop_upEtymology
  From lutum– mud and the suffix -ensis– indicating origin or place so ‘living in mud’ to emphasise the habitat that Romagnesi associated with this taxon, i.e. moist places with stagnant water.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileo 1,8–5,5 cm primum convexo, deinde expanso, saepe eximie irregulari et ad marginem flexuoso ac lobato, interdum circum albido, medio castaneo vel saltem e fulvido ochraceo, viscoso, glabro. Stipite curto, (1,5)–2–5,5 cm x 3,5–7 mm, cylindrato vel inferne leviter incrassato, candido, deinde paulum brunnescente, fibrilloso, atque primum fere toto farinoso. Carne medio crassa, alba, paulum in stipite ex ochraceo rufulo colore tincta, odore levi, potius cacaino quam rapaceo, sapore amaro. Lamellis distantibus, praesertim in veteribus speciminibus, latis vel etiam latissimis, (3–)4–10 mm, sinuatis, falciformibus vel ventricosis, deinde segmentiformibus vel fere triangulis, pallidissime brunneolis, deinde umbrinis, acie eximie serrulata ac punctis albis praedita, plorante. Sporis in cumulo umbrinis, 10–12–(12,5) x 5,2–6–(6,5) μm, amygdaliformibus, pallide luteis s.m., verruculosis. Pilis acierum claviformibus, interdum paulum haud procul a basi ampullaceis, brevioribus quam apud populinum, 35–57 x 6,5–10,5 μm. Epicute ex hyphis filiformibus, 1,5–2,8 μm praeditis, cute hyphis amplioribus, sub cute specie pseudoparenchymatica manifesta; pigmento membranari, interdum etiam incrustante, praesertim in hyphis connexivis cutis subcutisque. - In limo stagni, prope Salices et betulas, inter Phragmites, Carices ac Hydrocotylas.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus 1.8–5.5 cm, convex at first then expanding, often remarkably irregular and with flexuose and lobed margin, sometimes white at margin, chestnut brown at centre or at least reddish ochre tinged, viscid, glabrous. Stipe short, (1.5) 2–5.5 cm × 3.5–7 mm, cylindrical or towards base slightly thickened, white then weakly browning, fibrillose, at first almost entirely pruinose. Context medium thick, white, in stipe weakly discolouring ochre to ochre red; smell weak, rather more like cocoa then raphanoid; taste bitter. Lamellae distant, especially in older specimens, broad to very broad, (3–)4–10 mm, sinuate, falciform to ventricose, later segmentiform or almost triangular, pale umber brown, with remarkably serrulate, white punctate and weeping edge. Spores in mass umber brown, 10–12–(12.5) × 5.2–6–(6.5) μm, amygdaloid, pale yellow under microscope, minutely warted. Marginal hairs claviform, sometimes with slightly swollen basal part, very short like in H. populinum, 35–57 × 6.5–10.5 μm. Epicutis made of filiform hyphae 1.5–2.8 μm wide, cutis made of wider hyphae, subcutis distinctly parenchymatical. Pigment membranal, sometimes encrusting, especially in the connective hyphae in cutis and subcutis. In moist places with stagnant water near Salix and Betula, among Phragmites, Carex spp. and Hydrocotyle.

Description

Description of Hebeloma lutense based on 103 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (10) 23–38 (59) mm diameter; shape often convex, occasionally umbonate, rarely broadly umbonate or strongly umbonate; characters rarely spotting; margin characters often smooth, occasionally involute, rarely crenulate, ribbed or sulcate; viscosity tacky when moist; colour variation usually two color, rarely unicolour; colour at centre occasionally yellowish brown, rarely umber, cinnamon, dark fawn, orange-brown, dark brick, ochraceous, dark pinkish buff or sepia.

  Lamellae: attachment usually emarginate, rarely adnate or decurrent tooth; maximum depth 5–10 mm; number of complete lamellae 40–58; presence of tears usually visible with naked eye, rarely visible with x10 lens or absent; white fimbriate edge often present, occasionally weak, rarely very strong.

  Cortina presence: no.

  Stipe: (15) 27–48 (90) x 3–7 (11) {median} x 3–10 (18) {basal} mm; stipe Q 3.3–16.3; base shape often clavate or cylindrical, rarely bulbous or tapering; floccosity often pruinose, occasionally floccose, rarely weakly floccose, floccose at apex or pruinose at apex; rooting no; thick rhizoids at base absent;

  Context: Texture firm; stipe interior usually hollow, occasionally stuffed or superior wick; stipe flesh discolouring variable occasionally weak; slenderness measure 4.1–23.2; smell often raphanoid, occasionally weakly raphanoid, cocoa or odourless; taste bitter, rarely mild or raphanoid where recorded.

  Spore deposit colour: often brownish olive, occasionally umber.

  Exsiccata characters: occasionally shiny, rarely lamellae blackening or pileus blackening.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, rarely limoniform, ellipsoid or fusoid; colour in microscope often yellow brown, occasionally brown, rarely yellow pale; guttules variable. papilla often no, occasionally weak, rarely yes; Spore Code: O2 O3; P0 P1 (P2); (D1) D2.

  Basidia: 26–40 x 5–8 μm; ave. Q 4.0–5.7; spore arrangement 4 spored;

  Cheilocystidia: main shape usually clavate-stipitate, occasionally clavate-lageniform or clavate-ventricose, rarely capitate-stipitate, clavate, gently clavate or ventricose; special features observed often sinuate, occasionally septa or median thickening, rarely apical thickening, clamped septa, branching or mucous; cheilocystidia ratios: A/M = 1.63–2.39; A/B = 1.58–2.34; B/M = 0.95–1.22.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 180 μm; ixocutis hyphae width up to 5 μm; ixocutis hyphae encrustation often yes, occasionally no; shape of trama elements beneath subcutis often ellipsoid, thickly sausage-shaped or cylindrical, occasionally oblong up to 15 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 95 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma lutense's preferred habitat appears to be mixed woodland with decomposed litter. Where only one possible associate was recorded, the most commonly recorded associate was Salix (95.2%) but Pinus (3.2%) and Alnus (1.6%) were also recorded. In these cases the most commonly recorded family was Salicaceae (94.1%). We have additional records where Betula (16.2%), Quercus (14.1%) and Populus (6.1%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Salicaceae (86.9%), Betulaceae (28.3%), Fagaceae (14.1%) and Pinaceae (9.1%) The growth habit of our collections was often scattered, occasionally caespitose and rarely solitary or gregarious.

  According to our current collections, the species is predominantly found in Europe (99.0%) but also found in Northern America (1.0%). 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 (59.8%) and mediterranean forests, woodlands & scrub (27.5%), specifically including the ecoregions: Cantabrian mixed forests (21.6%), European Atlantic mixed forests (18.6%), Celtic broadleaf forests (14.7%) and Southwest Iberian Mediterranean sclerophyllous and mixed forests (14.7%). 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 Southwest (Spain, France, Portugal and Italy), the North (Isle Of Man, Scotland, Denmark, England and Norway) and the Centre (Belgium and Netherlands). Specimens have been collected from 39.5°N to 60.4°N.

  Within Northern America all our records are from Eastern Canada (Quebec).

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma lutense is monophyletic and receives high bootstrap in trees calculated from concatenated data of five to six loci. Additionally, the species is monophyletic with high bootstrap support in all tested loci apart from the ITS. In the ITS, H. lutense is very similar to H. alpinum and, hence, to members of the alpinum-complex. The sequence indicated as H. leucosarx is part of the original type collection, but not part of the lectotype of H. leucosarx and thus without taxonomic relevance.

• arrow_drop_downarrow_drop_upCommentary
  Given the shape of its cheilocystidia, Hebeloma lutense clearly belongs to H. subsect. Crustuliniformia and most likely corresponds to ICG9 of Aanen & Kuyper (1999). Its sinuate cheilocystidia and its consistently long thin basidia distinguish it from the other members of this subsection. Sinuate cheilocystidia do occur in other species, for example H. eburneum, but, in our experience, there is no other species where sinuate cheilocystidia occur so frequently and in such a consistent manner. Similarly, other species in this subsection can have quite long narrow basidia, but again this taxon has them consistently. The basidium Q for this taxon ranges from 4.0–5.7. Additionally, the number of complete lamellae less than 60, the average cheilocystidium apex width of less than 8 μm and the association with Salix, make it highly unlikely to miss-determine this taxon.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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