Hebeloma laetitiaeHebeloma laetitiae (Photo: L. Quadraccia)


Full name: Hebeloma laetitiae Quadr., Mycotaxon 49: 281 (1993)
Genus: Hebeloma
Section: Denudata
Subsection: Clepsydroida

Types: ITALY: Lazio, Castelporziano (Roma) (approx. 41.7441°N, 12.403°E, alt. approx. 60 m a.s.l.) on boggy soil under Quercus cerris, 30 Oct. 1986, L. Quadraccia (Holotype. herbarium acc. no. ROHB01093, HJB1000222; Isotype. herbarium acc. no. K(M)20801, HJB1000003).

  • arrow_drop_downarrow_drop_upEtymology
    Named in honour of his wife, Mrs Letizia Maravalli.
  • arrow_drop_downarrow_drop_upOriginal diagnosis
    Pileus 20–75 mm, primitus convexus, deinde expansus, fere praeditus lato umbone obtuso, interdum subexplanato, saepius +/- gibboso margine sinuato atque interdum lobato; cuticula aequali, +/- minute fibrillosa, subviscosa vel viscosa, margine integro vel subcostato, pruinoso; centro cremeo-flavidus, margine roseo vel roseo-flavido +/- uno eodemque modo albido-palaceus, colore roseo interdum tinctus, centro nonnunquam flavo-brunneus margine albido-argillaceo. Lamellae confertae, subconstrictae, emarginatae; lamellulae rotundatae, guttulas limpidas plorantes, postea brunneo maculatae; colore praeclaro, etiam in maturitate, argillaceae ex albidis, acie clariore erosa. Stipes 25–65 x 5–9 mm, rectus vel subsinuosus, cylindraceus vel +/- basi expansus, firmus, plenus vel farctus; uno eodem modo tenuiter flocculosus; albus vel albidus, subfuscescens praesertim in maturitate. Cortina abest. Caro in media sporocarpibus pileo subtilis, alba vel albida. Odore subnullo in speciminibus recenter collectis, subraphanoideo in sectis. Sapore subraphanoideo, subamaro. Sporae (10–)11–13(–14) x (5–)5.5–6.5(–7) μm, amygdaliformes vel subcitriformes, minutim sed dense verrucosae, subflavo colore perdiluto sub microscopio optico, parum nihilve dextrinoideae. Basidia 30–38 x 8–10 μm, tetrasporica, nonnunquam bisporica. Cheilocystidia (30–)40–65(–80 ) μm, primitus sublageniformia cum apice dilatato ac +/- ventricosa (usque ad 9 μm lata) postea claviformia vel subclaviformia, cum apice x 6–8(–9) μm, parum basi dilatata (x 3–5 μm), raro bifida vel ramosa, interdum monoseptata in proximali parte. Pleurocystldia adsunt. Caulocystidia chellocystidiis similia sed longiora ac saepius cylindraceo-capitu1ata. Epicutis ex ixocute manifesta constituta, quae quidem ex hyphis 2–4 μm) constat erectioribus, saepe in pileocystidia cheilocystidiis similia desinentibus. Cutis parum distincta ex hyphis maioribus (x 4–6 μm) constituta, recubantibus. Subcutis valde aucta, pseudoparenchymatica, ex hyphis pigmento membranario aurantiaco +/- coloratis constituta. Habitat: in silvis litoralibus planitiariis hygrophilis thermo-mesophilis sub frondosis ( id est Quercus cerris, Q. robur, Q. frainetto) saepe cum Quercus ilice et Quercus subere.
  • arrow_drop_downarrow_drop_upEnglish translation
    Pileus 20–75 mm diam., at first convex to broadly convex, then expanded, nearly always with wide obtuse umbo, at times subapplanate, more often gibbous with wavy margin sometimes lobate; surface uniform, +/- minutely fibrillose, subviscid to viscid, margin smooth or slightly ribbed, pruinose; cream-yellowish at the centre, pinkish to yellowish-pink at margin or +/- uniformly whitish-straw coloured with or without pinkish shades, sometimes yellowish-brown at the centre and clay-whitish at margin. Lamellae crowded, rather narrow, emarginate, lamellulae rounded, edged with limpid droplets, becoming brown spotted with age; pale coloured even at maturity, whitish to pale argillaceous, with paler, eroded edge. Stipe 25–65 × 5–9 mm, straight or subsinuate, cylindrical or more or less enlarged at base, firm, solid or stuffed, finely floccose all over, white or whitish, pale brown, especially at maturity. Cortina absent. Flesh thin at pileus centre, white or whitish. Smell not distinctive in freshly collected basidiomes, subraphanoid when cut. Taste subraphanoid, slightly bitter. Spores (10–)11–13(–14) × (5–)5.5–6.5(–7) μm, amygdaloid or subcitriform, minutely but densely verrucose, pale yellowish under the microscope, slightly or not dextrinoid. Basidia 30–38 × 8–10 μm, four-spored, sometimes two-spored. Cheilocystidia (30–) 40–65 (–80) μm, at first sublageniform with broadened apex and +/- ventricose (up to 9 μm broad), later clavate or subclavate with apex × 6–8 (–9) μm, slightly expanded at base (x 3–5 μm), seldom bifid or branched, sometimes with a single septum at the proximal part. Pleurocystidia absent. Caulocystidia similar to cheilocystidia but longer and more often cylindrical-capitate. Epicutis consists of an evident ixocutis, formed by slender rather erect hyphae (x 2–4 μm), often ending in pileocystidia similar to cheilocystidia. Cutis hardly distinguishable, formed by larger prostrate hyphae (x 4–6 μm). Subcutis evidently, pseudoparenchymatic, formed by hyphae coloured with orange membranal pigment. Habitat: in coastal damp thermo-mesophilic forests, under broadleaved trees (i.e. Quercus cerris, Q. robur, Q. frainetto) often also with Quercus ilex and Q. suber.


  • arrow_drop_downarrow_drop_upThresholds
Description of Hebeloma laetitiae based on 6 collections
  • arrow_drop_downarrow_drop_upMacroscopic description
    Pileus: (20) 47 (75) mm diameter; shape often convex or umbonate; characters Not recorded; margin characters often crenulate, involute or wavy; viscosity tacky when moist; colour variation unicolour; colour at centre occasionally cream, warm buff or yellowish brown, rarely pinkish buff or pale salmon.

    Lamellae: attachment emarginate; maximum depth not recorded; number of complete lamellae 50–60; presence of tears visible with naked eye; white fimbriate edge present.

    Cortina presence: no.

    Stipe: (25) 45 (65) x (5) 7 (9) {median} x (6) 7 (9) {basal} mm; stipe Q 5.0–7.2; base shape cylindrical, often clavate; floccosity floccose; rooting no; thick rhizoids at base often absent, occasionally present;

    Context: Texture firm; stipe interior stuffed; stipe flesh discolouring often no, occasionally yes; slenderness measure up to 6.3; smell often weakly raphanoid; taste weakly bitter or weakly raphanoid where recorded.

    Spore deposit colour: Not recorded.

    Exsiccata characters: Not recorded.

  • arrow_drop_downarrow_drop_upMicroscopic description
    Spores: shape amygdaloid, occasionally limoniform; colour in microscope often brown, occasionally yellow brown; guttules often no, occasionally yes. papilla variable often weak; Spore Code: O3; P1 P2; D2 D3.

    Basidia: 23–29 x 6–9 μm; ave. Q 3.3–3.9; spore arrangement Not recorded;

    Cheilocystidia: main shape clavate-lageniform or clavate-ventricose, often clavate-stipitate, occasionally clavate or ventricose; special features observed often septa or median thickening, occasionally geniculate, many collapsed in exsiccata or sinuate; cheilocystidia ratios: A/M = 1.78–2.02; A/B = 1.22–1.39; B/M = 1.45–1.59.

    Pleurocystidia: none seen.

    Ixocutis: epicutis thickness (measured from exsiccata) up to 250 μm; ixocutis hyphae width up to 6 μm; ixocutis hyphae encrustation no; shape of trama elements beneath subcutis thickly sausage-shaped up to 14 μm wide.

    Caulocystidia: Similar to cheilocystidia but larger, up to 75 μm.

  • arrow_drop_downarrow_drop_upSpore measurements
  • arrow_drop_downarrow_drop_upCheilocystidia measurements
  • arrow_drop_downarrow_drop_upHabitat and distribution
    Hebeloma laetitiae's preferred habitat appears to be mixed woodland, bog or Mediterranean woodland with acidic, boggy, sandy soil, acidic, boggy soil or boggy soil. Where only one possible associate was recorded, that associate has always been Quercus (family Fagaceae). We have additional records where Populus was recorded as a possible associate, but for these collections a number of possible associates were mentioned. Overall the most commonly recorded families are Fagaceae (100.0%) and Salicaceae (25.0%) The growth habit of our collections was scattered.

    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. mediterranean forests, woodlands & scrub (50.0%) and temperate broadleaf & mixed forests (50.0%), specifically including the ecoregions: Italian sclerophyllous and semi-deciduous forests (50.0%), English Lowlands beech forests (33.3%) and Western European broadleaf forests (16.7%). From collector information, it appears collections have been found in the 1.4 Forest – Temperate (66.7%) and 5.4 Wetlands (inland) – Bogs, marshes, swamps, fens, peatlands (33.3%) 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 Southeast (Italy), the North (England) and the Southwest (France). Specimens have been collected from 41.7°N to 51.6°N.

  • arrow_drop_downarrow_drop_upMolecular results
    ITS and V6 results support H. laetitiae as a good species. We have only sequences from a single collection for MCM7, RPB2 and Tef1a, which happens to be the English collection (HJB13642) discussed below. These loci also support that H. laetitiae is distinct from all other taxa. Only the V9 result (where H. laetitiae is paraphyletic with H. ingratum) does not. We are not aware of any published ITS sequences other than the ones published by us that are likely to belong to this species.
  • arrow_drop_downarrow_drop_upCommentary
    Given the shape of its cheilocystidia (primarily clavate-lageniform) and the spores mainly O3 and D2,D3, H. laetitiae belongs to H. sect. Denudata subsect. Clepsydroida. The species has most likely not been included in the intercompatibility tests of Aanen & Kuyper (1999). Within this subsection, the pink colour tones on the pileus separate this species from the other species with rather strongly dextrinoid spores (D3). Of our three database collections, two were collected near Rome in the same locality and the British collection is a “Hebelomina”, i.e. a white-spored collection where the exospore and perispore have not properly formed. Based on so few collections, we cannot be too sure with regard to the variation within the species. This is clearly a rare species and we really need to await more collections before we can have confidence in the characters and their consistency.
Geographic distribution
  • arrow_drop_downarrow_drop_upAdditional cited collections

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