Hebeloma duracinoides (Photo: H. J. Beker)

Taxonomy

Types: FRANCE: Ain, Mussel (approx. 46.1°N, 5.81°E, alt. approx. 500 m a.s.l.) on calcareous soil in deciduous woodland under Carpinus sp., Populus tremula, Quercus sp. and Tilia sp., 31 Oct. 1990, A. Bidaud, R. Fillion (AB- 90-10-315), det: A. Bidaud (Holotype. herbarium acc. no. Holotype: herb R. Fillion RF76-90; Isotype: herb A. Bidaud AB90-10-315, HJB1000124).

• arrow_drop_downarrow_drop_upEtymology
  From durus– hard and radix– root to emphasise the ‘rooted’ buried base of the stipe.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileus 30–70 mm latus, convexus, mammiformis, interdum fere trapezii speciem praebens, margine diu inflexa manente, fissile et valde lobata vel repanda, pruinose, aere sicco argentea; indumentum viscosum et hygrophanum, dein dessicans subtomentosum. Stipes 50–110 x 7–15 mm, radicans, farctus dein cavus, sursum pulveraceus, et media parte fibrillosus, colore cremeo, dein a basi olivaceo-brunneo. Cortina nulla vel fere nulla. Caro alba, in imo stipite brunnescens, odore farinoso et cacaino, sapore dulci. Lamellae parum confertae, late emarginatae vel rotundatae et in filum decurrentes, primum carneo-ochraceae, dein avellaneae. Sporarum depositum ochraceo-brunneum. Sporae 12–14 x 8,5–9,5 μm, amygdaliformes vel limoniformes. Marginis pilii breves, cylindracei vel clavati, 35–40 x 6–8 μm, Epicuti gelificata, ex hyphis gracilibus (x 3–5 μm), hypoderma pseudoparenchymaticum. Haec species in lutosis humis, congregata, sub mixtis arboribus frondosis crescit.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus 30–70 mm broad, convex, with umbo, sometimes trapezoid, with margin staying involute for a long time, fissile and strongly lobed and wavy, pruinose, silvery when dry; epicutis viscid, hygrophanous, becoming tomentose on drying. Stipe 50–110 × 7–15 mm, rooting, stuffed then hollow, pulverulent at apex, fibrillose in middle part, cream-coloured, then turning olivaceous brown at base. Cortina absent or almost absent. Context white, in base of stipe turning brown; odour farinaceous or like cocoa, taste sweet. Lamellae not very crowded, broadly emarginate or rounded-attached and with a small decurrent tooth, incarnate-ochraceus at first, then pale brown. Spore print ochre-brown. Spores 12–14 × 8.5–9.5 μm, amygdaloid or limoniform. Marginal hairs short, cylindrical to clavate, 35–40 × 6–8 μm. Epicutis gelatinised, of narrow hyphae (× 3–5 μm), hypoderm pseudoparenchymatical. This species grows in humid, muddy places in groups, under mixed deciduous trees.

Description

Description of Hebeloma duracinoides based on 14 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (30) 47–59 (70) mm diameter; shape often umbonate, occasionally weakly umbonate; characters usually hygrophanous, occasionally remains of universal veil or spotting; margin characters occasionally eroded, involute, crenulate or smooth; viscosity tacky when moist; colour variation usually unicolour, occasionally two color; colour at centre often umber, occasionally sepia or yellowish brown.

  Lamellae: attachment emarginate; maximum depth 5–9 mm; number of complete lamellae 48–60; presence of tears absent; white fimbriate edge often very strong, occasionally present, rarely absent or weak.

  Cortina presence: no.

  Stipe: (50) 70–81 (110) x (7) 10–12 (15) {median} x (6) 8–12 (18) {basal} mm; stipe Q 5.2–11.2; base shape usually cylindrical, often tapering; floccosity usually fibrillose, occasionally floccose, floccose at apex or pruinose at apex; rooting usually no, occasionally yes; thick rhizoids at base absent;

  Context: Texture firm; stipe interior hollow or superior wick, often stuffed; stipe flesh discolouring often very strongly, occasionally yes or weak; slenderness measure 7.5–15.5; smell occasionally cocoa, odourless or fruit, rarely farinaceous, raphanoid or weakly raphanoid; taste mild where recorded.

  Spore deposit colour: Not recorded.

  Exsiccata characters: often pileus blackening, occasionally dark, rarely hard.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, usually limoniform; colour in microscope occasionally brown, brown yellow, yellow or yellow brown; guttules no. papilla often very strongly, occasionally yes; Spore Code: O3 O4; P2 P3; (D3) D4.

  Basidia: 29–44 (45) x 7–10 (11) μm; ave. Q 3.4–5.0; spore arrangement 4 spored;

  Cheilocystidia: main shape cylindrical, occasionally clavate, ventricose or lageniform, rarely gently clavate or utriform; special features observed often septa, occasionally branching, irregular, mucronate, bifurcate, clamped septa or grotesque, rarely distorted, rostrate, short or sinuate; cheilocystidia ratios: A/M = 1.03–1.19; A/B = 0.93–1.23; B/M = 0.93–1.25.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 60 μm; ixocutis hyphae width up to 12 μm; ixocutis hyphae encrustation variable; shape of trama elements beneath subcutis often ellipsoid, isodiametric, polygonal or thickly sausage-shaped up to 20 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 200 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma duracinoides's preferred habitat appears to be deciduous woodland with soil and litter or calcareous soil. Where only one possible associate was recorded, that associate has always been Quercus (family Fagaceae). We have additional records where Carpinus, Corylus, Populus, Fagus, Tilia, Abies, Ostrya and Picea were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Fagaceae (92.9%), Betulaceae (42.9%), Salicaceae (14.3%), Pinaceae (14.3%) and Malvaceae (7.1%) The growth habit of our collections was often scattered and occasionally gregarious, caespitose or connate.

  According to our current collections, the species is found only in Europe. On the continent, 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 (78.6%) and mediterranean forests, woodlands & scrub (21.4%), specifically including the ecoregions: Appenine deciduous montane forests (35.7%), Western European broadleaf forests (21.4%), European Atlantic mixed forests (21.4%) and Italian sclerophyllous and semi-deciduous forests (14.3%). 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 Southeast (Italy), the Southwest (France and Spain) and the Centre (Germany). Specimens have been collected from 39.8°N to 50.7°N.

• arrow_drop_downarrow_drop_upMolecular results
  This species forms a monophylum in all single loci analyses and in the five-locus result . The ITS clade includes the sequence of the isotype of H. duracinoides. Thus the identity of the species as delimited here is molecularly supported. Due to the isolated nature of the lineage, the species can be easily identified from molecular data within the context of European Hebeloma spp. We have not found any evidence of intraspecific variation that could indicate hidden taxa within this species. To date, no ITS sequences from other continents have been published that could belong to this taxon or are likely to belong to close relatives.

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma duracinoides is a distinctive Hebeloma sp., both macroscopically and microscopically. It is usually possible to recognise it in the field with its reasonably large stature and its dry looking pileus. Indeed in the field it resembles a Cortinarius sp., with which it has probably often been confused. The largely cylindrical but very irregularly shaped cheilocystidia, together with its tendency to root, the tapering stipe and lack of an annulus indicate H. sect. Scabrispora or H. sect. Naviculospora. Microscopically, it can easily be separated from all known members of these sections on account of the large spores (always greater than 7 μm average width). It is worth noting the unusual epicutis of this species, which did cause us to consider whether this taxon should be included within Hebeloma at all. The epicutis is an ixocutis, but the hyphae within the ixocutis do not resemble those of any other Hebeloma species of which we are aware. Many of the epicutis hyphae are capitate at their apex, with the apex up to 12 μm wide. The ixocutis is also rather thin, up to 60 μm.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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