Hebeloma birrus (Photo: J. Vesterholt)

Taxonomy

Basionym:
Agaricus birrus Fr. [“1836–1838”], Epicrisis Systematis Mycologici seu Synopsis Hymenomycetum: 179 (1838) ["1836-1838"]

Types: SWEDEN: Ostergotland at Rejmyre, NW of Norrkoping. (approx. 58.82°N, 15.92°E, alt. approx. 75 m a.s.l.) in coniferous woodland, 4 Sep. 1994, J. Vesterholt (94-390) (Neotype. herbarium acc. no. C-F-74732, HJB1000122). Neotype designated by Vesterholt, Fungi N. Eur. 3. 3: (2005) page 116.

Heterotypic synonyms:

• Hebeloma calyptrosporum Bruchet, Bull. Mens. Soc. Linn. Lyon 39, supplement 6: 125 (1970)
• Hebeloma longicaudum var. radicatum (Cooke) Sacc., Syll. Fung. 5: 801 (1887)
• Hebeloma radicatum (Cooke) Maire, Bull. Trimestriel Soc. Mycol. France 24 (2): 57 (1908)
• Agaricus longicaudus var. radicatus Cooke, Handbook of British Fungi Edn. 2: 164 (1886)
• Hebelomatis calyptrosporum (Bruchet) Locq., Bull. Mens. Soc. Linn. Lyon 39, supplement 6: 146 (1970),Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]
• Hebelomatis radicatum (Cooke) Locq., Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]

Homotypic synonyms:

• Inocybe birra (Fr.) P. Karst. [as "birrus"], Bidrag Kännedom Finlands Natur Folk 32: 469 (1879)
• Hylophila birra (Fr.) Quélet, Enchiridion Fungorum in Europa Media et Praesertim in Gallia Vigentium: 99 (1886)

• arrow_drop_downarrow_drop_upEtymology
  From birrus– of yellow colour.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  A. birrus, pileo carnoso convexo-plano discoideo, circa marginem fibris superficialibus fasciculatis albis squamoso, stipite solido fusiformi-radicato, floccis albis squamoso-imbricatis sublanato apice farinoso fibrillosoque cortinato, lamellis rotundatis dein truncato-liberis confertis punctatis argillaceis. In fagetis umbrosis raro. Odor debilis, minime Raphani. Stipes 3 unc. l. 3 lin. cr. tenax, rectus. Pileus 1.5 unc., crustallinus, disco ruguloso.

• arrow_drop_downarrow_drop_upEnglish translation
  Agaricus birrus. Pileus fleshy plano-convex, disc-shaped, near margin with white squamules arising from fasciculate superficial fibrils; stipe solid, fusiform, radicating, almost woolly with white, squamose-imbricate flocks, apex pruinose and with fibrillose cortina; lamellae rounded then truncate-free, crowded with clay-coloured spots. In shadowy Fagus forest, rare. Smell weak, slightly raphanoid. Stipe about 7.5 cm long, 6 mm wide, tough, straight. Pileus about 4 cm, the colour of bread crust, centre rugulose.

Description

Description of Hebeloma birrus based on 79 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (6) 16–45 (75) mm diameter; shape often convex, occasionally broadly umbonate or strongly umbonate, rarely umbonate, papillate or weakly umbonate; characters rarely hygrophanous or spotting; margin characters often smooth, occasionally crenulate, rarely involute, ribbed or serrate; viscosity tacky when moist; colour variation usually two color, rarely unicolour; colour at centre occasionally yellowish brown, rarely ochraceous, clay-red, orange-brown, buff-yellow, umber, dark pinkish buff, dark brick, cinnamon or dark fawn.

  Lamellae: attachment often emarginate, rarely adnate or adnexed; maximum depth 3–7 mm; number of complete lamellae 30–55; presence of tears usually absent, rarely visible with naked eye; white fimbriate edge often present, occasionally weak or absent.

  Cortina presence: no.

  Stipe: (19) 29–74 (100) x (2) 3–7 (14) {median} x (2) 3–9 (18) {basal} mm; stipe Q 3.9–18.7; base shape occasionally cylindrical, clavate or tapering, rarely bulbous; floccosity occasionally floccose, pruinose at apex or pruinose, rarely fibrillose, floccose at apex, weakly floccose or transverse; rooting often yes, occasionally weak or no; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often hollow, occasionally stuffed; stipe flesh discolouring often yes, occasionally weak or no; slenderness measure 10.5–45.0; smell occasionally odourless, rarely cocoa, fruit, tea, raphanoid, soap or weakly raphanoid; taste often mild, occasionally bitter or weakly bitter, rarely hot where recorded.

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

  Exsiccata characters: occasionally shiny, rarely pileus blackening, pileus cracking or rich brown color.

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

  Basidia: 20–33 (34) x 5–8 μm; ave. Q 3.0–5.0; spore arrangement 4 spored;

  Cheilocystidia: main shape cylindrical, rarely clavate, lageniform, ventricose, utriform or gently clavate; special features observed occasionally short or septa, rarely clamped septa, apical thickening, median thickening or wavy; cheilocystidia ratios: A/M = 1.00–1.25; A/B = 0.94–1.23; B/M = 0.96–1.24.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 300 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation often yes, occasionally no; shape of trama elements beneath subcutis occasionally angular or thinly sausage-shaped, rarely cylindrical, hyphae thin or polygonal.

  Caulocystidia: Similar to cheilocystidia but larger, up to 150 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma birrus's preferred habitat appears to be coniferous woodland with decomposed litter. Where only one possible associate was recorded, the most commonly recorded associate was Pinus (45.0%) but Quercus (20.0%), Fagus (10.0%), Picea (10.0%), Castanea (5.0%), Betula (2.5%), Salix (2.5%), Abies (2.5%) and Cistus (2.5%) were also recorded. In these cases the most commonly recorded families were Pinaceae (54.5%) and Fagaceae (34.1%). We have additional records where Alnus was recorded as a possible associate, but for these collections a number of possible associates were mentioned. Overall the most commonly recorded families are Pinaceae (50.0%), Fagaceae (35.9%), Betulaceae (17.2%) and Salicaceae (12.5%) The growth habit of our collections was usually scattered, occasionally caespitose and rarely solitary or gregarious.

  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 (47.4%), mediterranean forests, woodlands & scrub (30.3%) and temperate conifer forests (11.8%), specifically including the ecoregions: Iberian conifer forests (19.7%) and European Atlantic mixed forests (11.8%). 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 North (England, Norway, Denmark, Scotland, Wales, Northern Ireland and Sweden), the Southwest (Spain, France and Italy), the Centre (Belgium, Germany and Austria), the Southeast (Italy) and Eastern Europe (Estonia). Specimens have been collected from 40.0°N to 60.3°N.

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma birrus is closely related with H. anthracophilum from which it cannot be differentiated based on ITS data. However, Hebeloma birrus receives excellent bootstrap support in the five-locus phylogeny as well as in the single locus results of V6, RPB2 and Tef1a and it is monophyletic but without bootstrap support in the V9 result. We obtained not only ITS, but also V6 and V9 sequences from the types of H. birrus and H. calyptrosporum. These results clearly support the assignment of the name H. birrus to this clade and the synonymization of the two species. As mentioned for H. anthracophilum, we are not aware of any published ITS sequences that might belong to either of these two species from outside Europe.

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma birrus is without annulus and this together with its tendency to root and the short, mainly cylindrical cheilocystidia place this taxon firmly within H. sect. Scabrispora. However, when the rooting is not obvious it may be difficult, at least microscopically, to separate this taxon from some members of H. sect. Naviculospora. Within the group of taxa with primarily cylindrical cheilocystidia, H. birrus may be distinguished by the spore size (9.1–10.8 × 5.0–6.3 μm) and the strongly and constantly loosening perispore. In the past many species, both North American and European, have been synonymized with Hebeloma birrus. We now believe that many of these synonyms are incorrect. Certainly species like H. nitidum and H. politum, both from North America, are distinct from this taxon. Also, we now know that H. anthracophilum, H. danicum and H. pumilum are different from H. birrus. Hebeloma danicum has spores of similar length to H. birrus, but they are rarely with strongly and constantly loosening perispore (P3). Hebeloma anthracophilum and H. pumilum do have spores P3, but these three taxa can be separated on average spore length: Hebeloma pumilum 7.9–8.9 μm, H. birrus 9.1–10.8 μm and H. anthracophilum 11.0–11.9 μm. It is worth noting that in Vesterholt (2005) there are three photographs of what he regarded (at the time) as H. birrus. The first of these, on p. 117, is indeed the neotype of H. birrus. Of his two photographs on p. 119 the first of these (JV02-890) is the taxon we call H. pumilum and the second (JV00-617) is the taxon we call H. anthracophilum. Hebeloma calyptrosporum is morphologically and molecularly similar to H. birrus and we have preserved this synonymy.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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