Hebeloma cylindrosporum (Photo: H. J. Beker)

Taxonomy

• arrow_drop_downarrow_drop_upNomenclatural notes
  The name Hebeloma cylindrosporum Romagn. has been conserved against H. angustispermum A. Pearson; it was proposed by Vesterholt et al., Taxon 58: 15 (2009), recommended by Norvell, Taxon 60: 224 (2011) and ratified by Barrie, Taxon 60: 1212 (2011).

Types: FRANCE: Oise, Foret d'Ermenonville near Bosquet du Prince, La Fontaine (approx. 49.15°N, 2.65°E, alt. approx. 110 m a.s.l.) on acidic, mossy soil and litter in coniferous dune woodland under Pinus pinaster and Pinus sylvestris, 27 Oct. 1961, H. Romagnesi (61.262) (Holotype. herbarium acc. no. PC0088805, HJB1000142; Isotype. herbarium acc. no. L 0054087, HJB1000013).

Heterotypic synonyms:

• Hebeloma angustispermum A. Pearson nom. rej., Transactions of the British Mycological Society 33 (3-4): 301 (1951) ["1950"]
• Hebeloma cylindrosporum f. pseudoradicatum (Bon) Migl. & Bon, Bollettino della Associazione Micologia ed Ecologica Romana 4 (10): 29 (1987)
• Hebeloma cylindrosporum var. pseudoradicatum Bon, Fungorum Rariorum Icones Coloratae: 27 (1979)

• arrow_drop_downarrow_drop_upEtymology
  From cylindrus– (Greek) cylindrical and sporus– spored to emphasise the cylindrical shape of the spores; until now no other species of Hebeloma has been discovered with such shaped spores.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileo 2,5–5,5 cm, pulvinato, dein expanso, interdum subdepresso, margine abrupta, dein expansa, medio e rufo brunneo, circumpallidiore, viscidulo, lucido. Stipite 1,3–9 cm x 3–10 mm, saepe inferne attenuato, pallido, dein e rufulo brunneo tincto, flocculoso. Cortina fugacissima. Carne crassa, pallida, modice brunnescente, odore herbaceo, grato, sapore amaro. Lamellis ± stipatis, inaequalibus, latis (4–10 mm), sinuatis, adnexis vel liberis, ex argillaceis brunneis, deinde vividius e rufis brunneis acie pallida. Sporis in cumulo vivide brunneis. anguste cylindrato-ellipsoideis, obtusis, 7,7–9–(11) x 4,2–4.7 μm, perispora distincta, manifeste verrucosis, vivide coloratis sub lente. Pilis acierum minimis, lageniformibus vel ciliformibus, 18–30 x 4–7 μm. Subcute specie minus pseudoparenchymatica quam apud multa alia Hebelomata. - In pinetis arenosis, tardus.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus 2.5–3.5 cm, cushion shaped (pulvinate) then expanding, sometimes slightly depressed, with abrupt then expanding margin, at centre first reddish then brown, paler towards margin, slightly viscid, shiny. Stipe 43–90 × 3–10 mm, often narrowed towards base, pale, then turning reddish then brown, flocculose. Cortina very fugacious. Context thick, pale, moderately browning. Smell herbaceous, pleasant. Taste bitter. Lamellae fairly crowded, unequal, broad (4–10 mm), sinuate, adnexed then free, first clay-coloured then brown, finally vivid reddish brown with paler edge. Spore print vividly brown; narrowly cylindrical to ellipsoid, blunt, 7.7–9(–11) × 4.2–4.7 μm, with distinct perispore, strongly verrucose, vividly coloured under microscope. Marginal hairs small, lageniform to cylindrical, 18–30 × 4–7 μm. Subcutis less parenchymatical than in many other Hebeloma species. In pine wood on sandy soil, late in season.

Description

Description of Hebeloma cylindrosporum based on 42 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (10) 12–40 (64) mm diameter; shape convex, rarely applanate; characters rarely hygrophanous; margin characters often smooth, occasionally involute, rarely scalloped, crenulate, eroded, ribbed, sulcate or wavy; viscosity tacky when moist; colour variation usually two color, rarely unicolour; colour at centre often yellowish brown, occasionally dark brick, rarely cinnamon.

  Lamellae: attachment usually emarginate, occasionally adnate, rarely adnexed; maximum depth 3–10 mm; number of complete lamellae 32–64; presence of tears often absent, occasionally visible with x10 lens; white fimbriate edge often absent, occasionally weak or present.

  Cortina presence: no.

  Stipe: (15) 28–66 (90) x 3–6 (10) {median} x 3–9 (14) {basal} mm; stipe Q 4.3–14.7; base shape usually cylindrical, occasionally clavate, rarely tapering or sand bulb; floccosity occasionally pruinose, fibrillose, pruinose at apex or floccose, rarely fibrous or weakly floccose; rooting variable rarely weak; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often hollow, occasionally stuffed or superior wick, rarely basal wick; stipe flesh discolouring variable occasionally weak, rarely very strongly; slenderness measure 7.2–34.0; smell often odourless, occasionally earthy, rarely fruit, cocoa or raphanoid; taste often bitter, occasionally mild where recorded.

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

  Exsiccata characters: occasionally shiny, rarely pileus blackening.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape cylindrical, rarely ellipsoid; colour in microscope often brown, occasionally yellow brown, rarely beige or yellow; guttules often yes, occasionally no, rarely weak. papilla no; Spore Code: (O1) O2; P1 P2; D3 (D4).

  Basidia: (16) 17–27 x 5–7 μm; ave. Q 2.7–4.1; spore arrangement 4 spored;

  Cheilocystidia: main shape cylindrical, often ventricose, occasionally lageniform, rarely clavate-lageniform or clavate-ventricose, gently clavate or filiform; special features observed often short, occasionally branching, rarely septa, bifurcate, clamped septa, irregular, geniculate, apical thickening, median thickening or mucronate; cheilocystidia ratios: A/M = 0.95–1.26; A/B = 0.69–1.15; B/M = 1.00–1.71.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 280 μm; ixocutis hyphae width up to 5 μm; ixocutis hyphae encrustation yes; shape of trama elements beneath subcutis often cylindrical, ellipsoid or thickly sausage-shaped, occasionally isodiametric or thinly sausage-shaped up to 20 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 cylindrosporum's preferred substrate appears to be sandy soil. Where only one possible associate was recorded, the most commonly recorded associate was Pinus (89.3%) but Cistus (7.1%) and Salix (3.6%) were also recorded. In these cases the most commonly recorded families were Pinaceae (88.9%) and Cistaceae (7.4%). We have additional records where Quercus (21.1%), Betula (2.6%) and Picea (2.6%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Pinaceae (86.8%), Fagaceae (21.1%) and Cistaceae (18.4%) 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 (90.2%) but also found in Africa (4.9%) and Temperate Asia (4.9%). 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. temperate broadleaf & mixed forests (52.5%), mediterranean forests, woodlands & scrub (30.0%) and unknown biome (12.5%), specifically including the ecoregions: Cantabrian mixed forests (25.0%), Unknown region (12.5%) and Baltic mixed forests (12.5%). From collector information, it appears collections have been found in the 13.3 Coastal Sand Dunes (51.7%) and 1.4 Forest – Temperate (37.9%) 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 Southwest (France, Portugal, Italy and Spain), the Centre (Poland and Germany), the North (Scotland, Denmark and England) and the Southeast (Italy). Specimens have been collected from 38.8°N to 57.3°N.

  Within Africa we have records from Macaronesia (Spain) and Southern Africa (South Africa).

  Within Temperate Asia all our records are from Western Asia (Cyprus).

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma cylindrosporum is molecularly distinct and monophyletic in all single locus results and in the five-locus result. The species receives high bootstrap support in the latter and in the V6, V9, RPB2 and Tef1a results. The synonymization of H. angustispermum and H. cylindrosporum (ITS1 only) and its variety H. cylindrosporum var. pseudoradicatum is supported by ITS data. We are not aware of any published ITS data from America or Asia that is likely to belong to H. cylindrosporum.

• arrow_drop_downarrow_drop_upCommentary
  Without annulus and with its tendency to root (although this is not always apparent) and its mainly cylindrical cheilocystidia this species clearly belongs to H. sect. Scabrispora. Within this subsection, and indeed within the genus as far as we are aware, the cylindrical spores are unique and make it relatively straightforward to identify this taxon. Hebeloma cylindrosporum does appear to favour sandy, base-poor soil with the presence of Pinus. We have synonymized H. cylindrosporum var. pseudoradicatum with this species as there appear to be no grounds for the separation. The rooting stipe appears to be dependent on the precise ecology of the habitat. Factors probably include the texture of the soil, the depth of the mycelium, the food sources available in the soil, e.g. roots, nests of insects or small rodents and so on. This is discussed quite fully in Grilli (2006). The type locality of H. cylindrosporum is the forest of Ermenonville (Oise) which lies to the north of Paris. At relatively low altitude (up to 200 m) the forests include plantations of Pinus sylvestris and Pinus pinaster and the soil is typically sandy, even forming internal dunes, similar to littoral dunes and exhibiting a similar flora. The species is common in the temperate Atlantic sand dune forests of Pinus pinaster and Pinus pinea along the south west coast of France where this taxon has been extensively studied by various French researchers (see below). Gröger (1987b) proposed that H. spoliatum should be regarded as a synonym of H. cylindrosporum. As argued by Vesterholt (2005) and Grilli (2006), it is unlikely that the species escribed by Fries as H. spoliatum was the same taxon. Hebeloma spoliatum was described from a mountainous coniferous forest in Sweden. We have no collections of this taxon from such habitats and we suspect that it does not grow in such habitats. While it is difficult to be certain of the taxon represented by H. spoliatum, we suspect that it probably represents H. birrus or, perhaps even more likely, H. syrjense. Hebeloma cylindrosporum is one of the most intensively studied species of ectomycorrhizal fungi. It is used as a model because its mycelium is easy to grow in vitro and its entire life cycle can be completed under controlled conditions (Debaud et al. 1987; Marmeisse et al. 2004). This latter feature has so far not been achieved for any other ectomycorrhizal fungus. These properties of this species have allowed scientists to explore different fields of mycorrhizal esearch, such as physiology, molecular functioning, ecology and population genetics, and to make significant advances in understanding the biology of mycorrhizal symbiosis. Grilli (2006) was the first to call attention to the synonymy of H. cylindrosporum with H. angustispermum. Sequence data derived from the holotypes of H. cylindrosporum (ITS sequence GenBank accession no. FJ769356) and H. angustispermum (ITS sequence GenBank accession no. J769357) confirmed Grilli’s results. Hebeloma angustispermum was first described by Pearson in 1951 from Bergvliet, an area south of Cape Town in the Cape Peninsula. Grilli argued that H. angustispermum should be regarded as an introduced species in South Africa and its centre of origin could be located in Atlantic, sub-Atlantic and Mediterranean areas of Europe. He suspected that it was brought in with the Pinus pinea and Pinus pinaster trees that were introduced to this region of South Africa. In Vesterholt et al. (2009a, 2009b) we proposed the conservation of the name Hebeloma cylindrosporum. This was based on the fact that H. cylindrosporum is a widely used name, in particular by many researchers working on mycorrhizas. The importance of the name H. cylindrosporum in academic research can be demonstrated by the number of citations in scientific literature using this name. A bibliographic search through two major international databases of scientific literature at the time of publication, ISI Web of Science and Scopus, recorded the name Hebeloma cylindrosporum in the title of 67 scientific publications and in at least 585 different published works originating from 30 different countries. By comparison, a similar search using the name Hebeloma angustispermum as input failed to find any record. The proposal was accepted in Norvell (2011).

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

Image gallery