Hebeloma laterinum (Photo: M. Ghyselinck)

Taxonomy

• arrow_drop_downarrow_drop_upNomenclatural notes
  The nomenclature adopted here follows the proposal to conserve the name Agaricus laterinus over the sanctioned name Agaricus fastibilis (Beker et al. 2014), which was accepted by the Nomenclature Committee for Fungi (May 2015), and endorsed by the General Committee (Wilson, 2017).

Basionym:
Agaricus laterinus Batsch, Elench. Fung. 2: 195 (1789)

Types: Batsch, Elench. Fung. 2: 106 (1789) t. XXXIII, fig 195a–b, lectotype (icon) designated by Beker et al., Taxon 62 (5): (2013) page 1060 GERMANY: Baden-Württemberg, Hochwald, Locherhof (48.1678°N, 8.5025°E, alt. approx. 705 m a.s.l.) on calcareous, grassy, mossy soil in coniferous woodland under Abies alba and Picea sp., 12 Oct. 2011, M. Ghyselinck (Epitype. herbarium acc. no. BR MYCO 173990-69 (epitype), C C-F-90145 (isoepitype), HJB13824). Epitype designated by Beker et al., Taxon 62 (5): (2013) page 1060.

Heterotypic synonyms:

• Hebeloma edurum Métrod, Revue de Mycologie 11: 80 (1946)
• Hebeloma edurum Métrod ex Bon, Documents mycologiques 16 (61): 16 (1985)
• Hebeloma fastibile (Pers.) P. Kumm. nom. rej., Der Führer in die Pilzkunde: 80 (1871)
• Hebeloma fusiformiradicatum (Britzelm.) Sacc. [as "fusiformi-radicatum"], Hedwigia 35 (7): 6 (1896)
• Hebeloma nigricans Velen., Ceske Houby: 393 (1919) ["1920"]
• Hebeloma senescens Berk. & Broome, Annals and Magazine of Natural History 5th Ser. 9: 178 (1882)
• Agaricus senescens Batsch, Elench. Fung. 2: 35 (1789)
• Agaricus fastibilis Pers. : Fr., Synopsis Methodica Fungorum (Gottingen): 326 (1801)
• Agaricus fusiformiradicatus Britzelm. [as "fusiformi-radicatus"] ., Bot. Centralbl. 62: 279 (1895)
• Hebelomatis edurum Locq. [ as "(Métrod) Locq."], Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]
• Roumeguerites fastibilis (Pers.) P. Karst., Meddelanden af Societas pro Fauna et Flora Fennica 9: 59 (1883)
• Inocybe fastibilis (Pers.) P. Karst., Bidrag Kännedom Finlands Natur Folk 32: 467 (1879)
• Hylophila fastibilis (Pers.) Quél., Enchiridion Fungorum in Europa Media et Praesertim in Gallia Vigentium: 98 (1886)
• Picromyces fastibilis (Pers.) Earle, Bulletin of the New York Botanical Garden 5 (18): 438 (1909)

• arrow_drop_downarrow_drop_upEtymology
  Batsch described this species as “the brick-reddish fleshy fungus”, lateritius– brick red. So laterinus was presumably derived from lateritius.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileo lateritio-carneo, pulvinato, farto, subviscido, stipite concolore pallidiore, floccoso-aspero, laminis fulvellis angustis. Fungus vere validus, fartus, sed minus proportione, quam colore et superficie determinandus. Pileus superficie gauder opaca, delicata, alutacea, et subviscida, siccitate magis rubente. Margo vix extima ora tenuatus, vix involutus. Stipes forma varius, basi saepe crassiusculus, superficie opacus, omnis nitoris expers, crebris floccis laxis, revolutis, et laceris aspersus, pileum sustentans, vel lenissime cum eo confluens. Laminae laxae, angustae erga pilei crassitiem, inferne rectilineae, pone obtusatae et latiores, marginibus et alternatione inaequales, umbris obscurioribus et margine obsolete albentiore crenulatoque instructae. Majores circiter 60–80, pileo soli adnatae. Substantia densa suberoso carnosa, alba, pallidissime in fungi totius colorem vergens, in stipite fibrosa. Inveni frequentes hosce fungos in pinetis sylvulae Rauhethal dic 20 Sept. 1788. Icones. a. Fungi bini, sociales, graciliores, integri. b. Alius dissectus, crassior, et solitarius.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus brick-red, incarnate, convex, solid, subviscid, with pale, but similarly coloured stipe, floccose-rough; lamellae adnate, reddish brown. A well delimited fungus, firm, but of small proportion, distinguished by its colour and surface. The pileus has an opaque, fine, delicately leathery, somewhat sticky surface which turns to a more reddish colour on drying. The thick pulvinate cap is scarcely tapering towards the extreme margin where it is only scarcely involute. The stipe is variously shaped, often broadened at the base, the surface is opaque, not shining and covered with loose, fissured and backward-rolled flakes. The stipe supports the pileus and is only weakly confluent with it. The lamellae are flaccid, narrow in proportion to the pileus thickness, rectilinear below, obtuse and broader to the rear; their lengths alternate irregularly, they have dark spots and unequal, crenulate, somewhat more whitish edges. There are roughly 60-80 longer lamellae, they are only attached to the pileus. The context is compact, corky, fleshy, white and has a pale reflex of the reddish colour of the whole fungus. It is fibrillose in the stipe. I found these fungi growing abundantly under the pine trees in the Rauhtal valley, on 20 Sep. 1788. Figures. a. Two entire, more slender fungi grown together at the base. b. Another, single, thicker fungus, in section.

Description

Description of Hebeloma laterinum based on 139 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (20) 28–78 (96) mm diameter; shape often convex, occasionally broadly umbonate, rarely umbonate; characters occasionally spotting, rarely remains of universal veil, rimulose, pruinose or rugulose; margin characters often smooth, occasionally involute, rarely crenulate, eroded, scalloped, serrate or sulcate; viscosity tacky when moist; colour variation usually unicolour, rarely two color; colour at centre occasionally dark pinkish buff or pinkish buff, rarely cream, yellowish brown, pale cream, honey, ochraceous, pale pinkish buff, dark brick, umber, orange-brown, clay-buff or cinnamon.

  Lamellae: attachment usually emarginate, rarely adnate or adnexed; maximum depth 3–10 mm; number of complete lamellae 40–130; presence of tears usually absent, rarely visible with x10 lens or visible with naked eye; white fimbriate edge occasionally present or weak, rarely absent.

  Cortina presence: usually no, rarely yes.

  Stipe: (16) 30–84 (120) x 5–13 (26) {median} x (5) 6–19 (33) {basal} mm; stipe Q 2.4–12.5; base shape often clavate, occasionally cylindrical, rarely bulbous or tapering; floccosity often floccose, rarely floccose at apex, fibrillose, pruinose at apex, velute or none; rooting often yes, occasionally weak or no; thick rhizoids at base usually absent, rarely present;

  Context: Texture firm; stipe interior often stuffed, occasionally hollow, rarely superior wick; stipe flesh discolouring usually very strongly, rarely yes or weak; slenderness measure 2.6–23.4; smell occasionally fruit, odourless or cocoa, rarely tea, earthy, soap, raphanoid or strongly raphanoid; taste often bitter or weakly bitter where recorded.

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

  Exsiccata characters: occasionally hard or dark, rarely rich brown color, fragile, lamellae blackening, pileus blackening, shiny or stipe blackening.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape usually amygdaloid, rarely limoniform, ellipsoid or ovoid; colour in microscope often yellow brown, occasionally brown, rarely brown yellow, grey yellow, very pale or yellow; guttules usually yes, rarely no. papilla often no, rarely yes, weak or very strongly; Spore Code: (O2) O3; P1 P2; D3 (D4).

  Basidia: (21) 23–34 (35) x (5) 6–8 (10) μm; ave. Q 3.0–5.1; spore arrangement 4 spored;

  Cheilocystidia: main shape usually cylindrical, rarely ventricose, lageniform, clavate, balloon-shaped, gently clavate, clavate-lageniform or clavate-ventricose or utriform; special features observed often septa, occasionally clamped septa, short or branching, rarely bifurcate, rostrate, conglutinate, irregular, geniculate, many collapsed in exsiccata, median thickening or mucronate; cheilocystidia ratios: A/M = 0.92–1.23; A/B = 0.69–1.40; B/M = 0.83–1.51.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 250 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation variable; shape of trama elements beneath subcutis often isodiametric, occasionally ellipsoid, thickly sausage-shaped, circular, cylindrical, thinly sausage-shaped or spherical up to 20 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 120 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma laterinum's preferred habitat appears to be mixed woodland or deciduous woodland with calcareous soil. Where only one possible associate was recorded, the most commonly recorded associate was Pinus (32.9%) but Quercus (17.8%), Fagus (15.1%), Picea (12.3%), Helianthemum (9.6%), Abies (2.7%), Salix (2.7%), Dryas (2.7%), Tilia (1.4%), Cedrus (1.4%) and Populus (1.4%) were also recorded. In these cases the most commonly recorded families were Pinaceae (53.6%), Fagaceae (30.9%) and Cistaceae (8.3%). We have additional records where Cistus (2.7%), Corylus (2.7%), Betula (2.7%) and Carpinus (2.7%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Pinaceae (60.4%), Fagaceae (38.7%), Cistaceae (9.0%), Salicaceae (8.1%) and Betulaceae (8.1%) 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 (99.2%) but also found in Temperate Asia (0.8%). 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. temperate broadleaf & mixed forests (58.7%), mediterranean forests, woodlands & scrub (27.3%) and temperate conifer forests (11.6%), specifically including the ecoregions: Western European broadleaf forests (24.0%) and Iberian sclerophyllous and semi-deciduous forests (10.7%). 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 (France and Spain), the Centre (Germany, Switzerland, Poland, Slovakia, Belgium, Austria and Czech Republic), the Southeast (Italy, North Macedonia, Slovenia and Greece), the North (England, Denmark, Norway and Finland) and Eastern Europe (Estonia). Specimens have been collected from 39.8°N to 64.2°N.

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

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma laterinum forms a joint clade with H. lindae in all phylogenetic results. In spite of the great similarity of the sequences, H. laterinum is monophyletic and reasonably well or well supported by bootstrap in four out of five single locus results and in the five-locus phylogeny. We are not aware of any published ITS data from outside Europe that is likely to belong to this species. There is one ITS sequence published that was retrieved from the roots of Orchis anthropophora (GQ907284, Lievens et al. 2010) that is likely to belong to H. laterinum.

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma laterinum is a macroscopically distinctive Hebeloma species that can usually be recognised in the field due its robust stature and the very floccose and blackening stipe. Furthermore it is often rooting. The tendency to root, the lack of an annulus and the short cylindrical cheilocystidia place this taxon firmly within H. sect. Scabrispora. Within this section it is distinguished by the characters mentioned above, but also by the number of lamellae (always greater than 65), the spore length (at least 9.5 μm), the spores with an ave. Q value of less than 1.9, mostly distinctly ornamented and rather strongly dextrinoid (O3; D3,D4), ut with the perispore not strongly and constantly loosening (not P3). The habitat also seems onsistent in being restricted to base-rich soils. The smell is never raphanoid. The species is also known under various other names: H. edurum, H. senescens, earlier also as H. sinuosum. Vesterholt (2004) argued that H. laterinum (A. laterinus) and H. senescens should be treated as synonyms. His argument was based on the descriptions and the two plates of Batsch (1789, pl. 195 and pl. 197). Both taxa show similarities in habitat and colours as well as in the floccose nature of the stipe. The subfasciculate growth and the tendency for the flesh to become sordid brown with age are also common characters. While the stipe of H. senescens may sometimes be hollow, it is equally often stuffed (solid) as illustrated in the plate of A. laterinus. Previously, in Kuyper and Vesterholt (1990), A. laterinus had been designated as lectotype for A. fastibilis (H. fastibile), superseding an earlier neotypification of this latter taxon by Singer. Singer’s neotypification would have led to H. fastibile and H. mesophaeum becoming synonyms, potentially necessitating changing the name used for one of the most commonly collected Hebeloma spp. In Beker et al (2013b) we proposed the conservation of the name A. laterinus against the sanctioned name A. fastibilis. We believe that this will provide nomenclatural stability.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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