Hebeloma bulbiferumHebeloma bulbiferum (Photo: H. J. Beker)


Full name: Hebeloma bulbiferum Maire, Publ. Inst. Bot. Barcelona 3 (4): 108 (1937)
Genus: Hebeloma
Section: Sinapizantia

Types: SPAIN: Barcelona, Catalaunia, Palautordera (approx. 41.7°N, 2.4°E, alt. approx. 210 m a.s.l.) under Pinus pinea and Quercus ilex, 20 Oct. 1933, R. Maire (Lectotype. held at herbarium MPU, HJB1000101). Lectotype designated by Grilli, Micol. Veg. Medit. 19 (2): (2004) page 94.

Heterotypic synonyms:

  • Hebeloma colossus Huijsman, Persoonia 2 (1): 98 (1961)
  • Hebelomatis colossus (Huijsman) Locq. [ as "colossum"], Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]

  • arrow_drop_downarrow_drop_upEtymology
    From bulbus– bulb, and fer– carrying, emphasizing the shape of the base of the stipe.
  • arrow_drop_downarrow_drop_upOriginal diagnosis
    Carpophora gregaria, circinantia, haud hygrophana: sapor amarus; odor debilis demum vix rapaceus; caro undique alba; sporae in cumulo fusco-ferrugineae. Stipes (6–8 cm. x 1,3–1,7 cm) bulbosus bulbo 2,5–2,8 cm crasso abrupte contracto sed immarginato, cum pileo confluens, fibroso-carnosus, e solido demum farctus, cute adnata, sicca, a bulbo usque ad apicem squamulis fibrillosis praedita, alba; cortina nulla. Pileus (5–8 cm diam.) convexus, crassus, margine tantum tenui, carnosus, cute separabili viscosa glabra, cremeo-ochracea; margo incurvus, estrius, albo-pruinosus. Lamellae tenues, subconfertae, lacrymantes, latae (usque ad 1 cm), cum pileo confluentes, ventricosae, postice leviter adnatae valde emarginatae, antice plus minusve adtenuatae, e dilute argillaceo fusco-ferrugineae, intus albae, acie valde pruinosa alba, haud intervenatae; lamellulae postice rotundatae. Lamellarum acies pilis filiformibus apice clavatis, dense fasciculatis heteromorpha; mediostratus regularis; subhymenium tenue; cystidia nulla; basidia cylindracea, 4-spora, 30–32 x 8 μ; sporae amygdaliformes, melleae, tenuiter et dense “verruculosae”, apice papillatae, basi in apiculum hilarem hyalinum contractae, 12–14 x 7–8 μ. Pilei cutis ex hyphis gracilibus (c. 3 μ diam.) laxe intertextis, gelificatis, contexta. Stipitis cutis ex hyphis parallelis inaequalibus (3–14 μ diam.), cylindraceis, constans, pilis filiformibus flexuosis, in fasciculos densos intertextis, apice clavatis, praedita. Hyphae fibuligerae.
  • arrow_drop_downarrow_drop_upEnglish translation
    Basidiomes gregarious, in circles, not hygrophanous, taste bitter, smell weak, later hardly raphanoid, context white in all parts, spores in mass brown-rusty brown. Stipe (6–8 cm × 1.3–1.7 cm) bulbous, 2.5–2.8 cm wide, abruptly shaped but not marginate, confluent with pileus, fibrous-fleshy, solid then hollow, with adnate cutis, dry, with white fibrillose squamules on bulb and at apex; cortina absent. Pileus (5–8 cm broad), convex, thick, margin barely thin, fleshy, cutis separable, viscous, glabrous, creamy-ochraceous, with white pruinose, incurved not striate margin. Lamellae thin, not very crowded, exuding droplets, broad (up to 1 cm), confluent with pileus, ventricose, attachment slightly adnate, strongly emarginate, more or less attenuate at margin of pileus, first diluted clay-coloured, then rusty brown, inner part white, edge white, strongly pruinose, not interveined; lamellulae rounded-attached. Lamella edge heteromorphic with dense clusters of filiform hairs with clavate apex; mediostratum regular; subhymenium thin; cystidia none; basidia cylindrical, four-spored, 30–32 × 8 μm; spores amygdaloid, honey-coloured, minutely and densely verruculose with papillate apex; base contracted in a hyaline apiculus, 12–14 × 7–8 μm. Pileipellis made of slender (ca. 3 μm wide), loosely interwoven, gelatinized hyphae. Stipitipellis composed of a cutis of parallel unequal, cylindrical hyphae, 3–14 μm wide, with dense cluster of filiform, flexuose hairs. Hyphae clamped.


  • arrow_drop_downarrow_drop_upThresholds
Description of Hebeloma bulbiferum based on 31 collections
  • arrow_drop_downarrow_drop_upMacroscopic description
    Pileus: (30) 41–99 (125) mm diameter; shape often convex, occasionally broadly umbonate, rarely umbonate; characters occasionally remains of universal veil; margin characters often involute, occasionally smooth, rarely scalloped; viscosity tacky when moist; colour variation usually unicolour, rarely two color; colour at centre occasionally ochraceous, dark pinkish buff or pinkish buff, rarely pale cream, cream or yellowish brown.

    Lamellae: attachment often emarginate, occasionally adnate, rarely decurrent tooth; maximum depth 3–17 mm; number of complete lamellae 80–120; presence of tears usually visible with naked eye, rarely absent; white fimbriate edge usually present, occasionally very strong.

    Cortina presence: no.

    Stipe: (20) 41–126 (145) x (10) 12–28 (35) {median} x (17) 19–43 (50) {basal} mm; stipe Q 1.7–8.4; base shape usually bulbous, occasionally clavate; floccosity floccose, rarely floccose at apex; rooting no; thick rhizoids at base absent;

    Context: Texture firm; stipe interior often hollow or stuffed, occasionally superior wick; stipe flesh discolouring usually no, rarely weak; slenderness measure 1.9–12.1; smell often raphanoid, occasionally strongly raphanoid or weakly raphanoid; taste often bitter, occasionally weakly raphanoid where recorded.

    Spore deposit colour: umber.

    Exsiccata characters: occasionally hard, rarely dark.

  • arrow_drop_downarrow_drop_upMicroscopic description
    Spores: shape amygdaloid, often limoniform; colour in microscope occasionally brown, very pale, yellow brown or yellow; guttules usually yes, rarely weak. papilla variable rarely weak or very strongly; Spore Code: (O2) O3 O4; (P0) P1 (P2); D4.

    Basidia: 27–45 (47) x 6–10 μm; ave. Q 3.9–4.7; spore arrangement Not recorded;

    Cheilocystidia: main shape usually clavate-stipitate, often clavate-lageniform or clavate-ventricose or gently clavate, occasionally capitate-stipitate or spathulate-stipitate, rarely ventricose, clavate, lageniform or subcapitate; special features observed often clamped septa, occasionally bifurcate, branching or septa, rarely geniculate, conglutinate, many collapsed in exsiccata, mucous or plaques; cheilocystidia ratios: A/M = 1.70–2.46; A/B = 1.32–2.06; B/M = 1.01–1.46.

    Pleurocystidia: none seen.

    Ixocutis: epicutis thickness (measured from exsiccata) up to 250 μm; ixocutis hyphae width up to 7 μm; ixocutis hyphae encrustation often yes, occasionally no; shape of trama elements beneath subcutis often thinly sausage-shaped, occasionally cylindrical, isodiametric or oblong up to 12 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 bulbiferum's preferred habitat appears to be deciduous woodland with calcareous soil or calcareous, decomposed soil and litter. Where only one possible associate was recorded, the most commonly recorded associate was Quercus (84.6%) but Pinus (15.4%) were also recorded. In these cases the most commonly recorded families were Fagaceae (85.7%) and Pinaceae (14.3%). We have additional records where Carpinus (30.8%), Fagus (3.9%), Populus (3.9%), Betula (3.9%) and Corylus (3.9%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Fagaceae (88.5%), Betulaceae (34.6%), Rosaceae (15.4%) and Pinaceae (11.5%) The growth habit of our collections was often scattered, occasionally gregarious and rarely caespitose.

    According to our current collections, the species is predominantly found in Europe (87.1%) but also found in Temperate Asia (12.9%). 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. mediterranean forests, woodlands & scrub (64.5%) and temperate broadleaf & mixed forests (35.5%), specifically including the ecoregions: Appenine deciduous montane forests (19.4%), Southwest Iberian Mediterranean sclerophyllous and mixed forests (19.4%), Italian sclerophyllous and semi-deciduous forests (16.1%) and Southern Anatolian montane conifer and deciduous forests (12.9%). 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, North Macedonia and Croatia), the Southwest (Portugal, France and Spain) and the North (England). Specimens have been collected from 38.7°N to 50.9°N.

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

  • arrow_drop_downarrow_drop_upMolecular results
    Hebeloma bulbiferum is monophyletic and well supported for all loci tested. The ITS is well suited for identifying this species. The synonymy of H. colossus with our concept of H. bulbiferum is supported by the ITS2 of H. colossus. We are not aware of any published ITS sequences from outside Europe that are likely to belong to this species.
  • arrow_drop_downarrow_drop_upCommentary
    Hebeloma bulbiferum looks macroscopically as if it belongs to H. section Sinapizantia, but microscopically it is rather different from the other member of this section. Indeed, microscopically it could well be mistaken for a member of H. sect. Denudata subsect. Echinospora. It does usually have gently clavate, slender cheilocystidia, but it also has clavate-stipitate and clavate-lageniform cheilocystidia, which are more reminiscent of H. sect. Denudata. However, all species within H. sect. Echinospora have spores with strongly and constantly loosening perispore (P3) whereas, although H. bulbiferum spores can have a loosening perispore, we have no collections where it is strongly and constantly loosening, i.e. it is at most P2 and never P3. Macroscopically, H. bulbiferum is very different from the members of H. subsect. Echinospora. The cheilocystidia and strongly dextrinoid spores may mean that this species is confused with members of H. sect. Velutipes, but no member of this section has such robust basidiomes and such a large number of full length lamellae (always at least 80). Within H. sect. Sinapizantia it is closely related, and potentially confused, with H. sinapizans (the only other European member of this section of which we are aware). But they are easily separated in the field (except perhaps in very dry conditions) because H. sinapizans never has drops on the lamellae and normally has a darker pileus than H. bulbiferum, which always has large drops on the lamellae and even in dry weather the tell-tale patches on the lamellae indicate where the drops were placed. Microscopically, the two taxa are very different with the clavate-stipitate or clavate-lageniform or gently clavate cheilocystidia of H. bulbiferum and the lageniform or ventricose cheilocystidia of H. sinapizans. Hebeloma colossus is a synonym of H. bulbiferum as was pointed out by Grilli (2004). The lectotype material of H. bulbiferum is unfortunately in very bad condition, and we have been unable to generate any sequences. However, there is no doubt that this taxon is well defined and the lectotype sufficiently demonstrates the important characters, so we have decided not to epitypify it.
Geographic distribution
  • arrow_drop_downarrow_drop_upAdditional cited collections

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