Hebeloma avellaneumHebeloma avellaneum (Photo: N. Siegel)


Full name: Hebeloma avellaneum Kauffman, Papers of the Michigan Academy of Science, Arts and Letters 17: 171 (1933)
Genus: Hebeloma
Section: Naviculospora

Types: UNITED STATES: Washington: Grays Harbor, Lake Quinault, Olympic National Park (approx. 47.4742°N, 123.8667°W, alt. approx. 75 m a.s.l.) on mossy soil in woodland bog edge, 8 Nov. 1925, C.H. Kauffman (Holotype. herbarium acc. no. MICH 10722, HJB1000322).

  • arrow_drop_downarrow_drop_upEtymology
  • arrow_drop_downarrow_drop_upOriginal diagnosis
    Caespitosum vel subcaespitosum; pileus 3-8 cm. latus, ovato-campanulatus, umbonatus demum expansus, avellaneus, valde viscosus; lamellae adnato-emarginatae vel adnatae, brevissime et angulatim decurrentes, angustae, confertae, avellaneae, acie albido-fimbriatae, non guttulatae; stipes 5-10 cm. longus, 6-12 mm. crassus, ovoideo-bulbosus, farctus, demum cavus, albido-furfuraceus, basi sericeus; sporae amygdaloideae, tuberculosae, 8-10 (11) x 5-5.5 μ.
  • arrow_drop_downarrow_drop_upEnglish translation
    Caespitose or subcaespitose; pileus 3-8 cm broad, ovate to campanulate, umbonate finally expanded, hazel brown, strongly viscous; lamellae adnate-emarginate or adnate, very shortly and angularly decurrent, narrow, crowded, hazel brown, with white, fimbriate edge, not beaded; stipe 5-10 cm long, 6-12 mm thick, ovoid to bulbous, stuffed, finally fistulose, whitish scurfy, silky at base; spores amygdaloid, tuberculate, 8-10 (11) x 5-5.5 μ.


  • arrow_drop_downarrow_drop_upThresholds
Description of Hebeloma avellaneum based on 17 collections
  • arrow_drop_downarrow_drop_upMacroscopic description
    Pileus: (25) 32–67 (119) mm diameter; shape often broadly umbonate, occasionally convex or umbonate; characters occasionally pruinose; margin characters often involute, occasionally smooth; viscosity tacky when moist; colour variation often unicolour, occasionally two color; colour at centre occasionally brick, ochraceous or clay-buff, rarely umber, yellowish brown or dark brick.

    Lamellae: attachment emarginate, rarely decurrent tooth; maximum depth 2–5 mm; number of complete lamellae 75–96; presence of tears usually absent, rarely visible with x10 lens; white fimbriate edge often weak, occasionally present, rarely very strong.

    Cortina presence: no.

    Stipe: (25) 29–80 (100) x (6) 9–16 (19) {median} x 7–18 (20) {basal} mm; stipe Q 1.4–10.2; base shape occasionally clavate, cylindrical or bulbous; floccosity often floccose, occasionally pruinose at apex, velute or floccose at apex; rooting often no, occasionally yes; thick rhizoids at base absent;

    Context: Texture firm; stipe interior usually hollow, occasionally stuffed; stipe flesh discolouring usually no, rarely weak; slenderness measure 0.8–14.5; smell occasionally odourless or weakly raphanoid, rarely cocoa, raphanoid, strongly raphanoid or soap; taste often mild, occasionally bitter or weakly raphanoid where recorded.

    Spore deposit colour: brownish olive.

    Exsiccata characters: shiny, occasionally fragile.

  • arrow_drop_downarrow_drop_upMicroscopic description
    Spores: shape amygdaloid, occasionally fusoid or limoniform, rarely navicular; colour in microscope yellow brown; guttules yes. papilla yes; Spore Code: O1 O2; (P0) P1; D3.

    Basidia: (21) 22–35 (36) x 5–8 μm; ave. Q 3.7–4.6; spore arrangement 4 spored;

    Cheilocystidia: main shape cylindrical, often gently clavate or clavate-lageniform or clavate-ventricose, occasionally ventricose, capitate-stipitate or clavate, rarely balloon-shaped or capitate; special features observed often irregular or septa, occasionally bifurcate, rarely branching, clamped septa, grotesque, distorted, geniculate or short; cheilocystidia ratios: A/M = 1.10–1.73; A/B = 0.96–1.84; B/M = 0.93–1.26.

    Pleurocystidia: usually none seen, rarely seen.

    Ixocutis: epicutis thickness (measured from exsiccata) up to 130 μm; ixocutis hyphae width up to 8 μm; ixocutis hyphae encrustation Not recorded; shape of trama elements beneath subcutis thinly sausage-shaped, often angular, circular, cylindrical, ellipsoid, hyphae thick, hyphae thin, isodiametric, oblong, ovate, polygonal, pyriform, thickly sausage-shaped, spherical or undefined up to 14 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
    Where only one possible associate was recorded, the most commonly recorded associate was Pinus (33.3%) but Picea (33.3%), Salix (16.7%) and Betula (16.7%) were also recorded. In these cases the most commonly recorded families were Pinaceae (80.0%), Salicaceae (10.0%) and Betulaceae (10.0%). We have additional records where Abies (37.5%), Tsuga (31.2%) and Populus (6.2%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Pinaceae (75.0%), Salicaceae (31.2%) and Betulaceae (6.2%) The growth habit of our collections was often solitary and occasionally caespitose or scattered.

    According to our current collections, the species is predominantly found in Northern America (81.2%) but also found in Temperate Asia (18.8%). 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 conifer forests (58.8%), boreal forests/taiga (17.6%) and temperate broadleaf & mixed forests (17.6%), specifically including the ecoregions: North Cascades conifer forests (23.5%), Colorado Rockies forests (17.6%), Caucasus mixed forests (11.8%) and Northern Canadian Shield taiga (11.8%). From collector information, it appears collections have been found in the 1.4 Forest – Temperate (38.5%), 1.1 Forest – Boreal (30.8%) and 5.11 Wetlands (inland) – Alpine wetlands (inc. temporary waters from snowmelt) (15.4%) 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 Northern America we have records from Northwestern U.S.A. (Washington and Colorado), Subarctic America (Nunavut and Alaska), Eastern Canada (Newfoundland and Labrador) and Southwestern U.S.A. (California).

    Within Temperate Asia we have records from Caucasus (Karachay-Balkar) and Western Asia (Turkey).

  • arrow_drop_downarrow_drop_upCommentary
    Based on our studies of this taxon and of the habitats where it has been collected, we strongly suspect that this species is typically associated with conifers in temperate to subalpine or subarctic habitats. The holotype was collected in a temperate rainforest within the Olympic Peninsula in western Washington state. The often pruinose pileus with distinctive orange tones is indicative of H. sect. Naviculospora. In subalpine habitats, the species might be confused with H. alpinum, H. velutipes, or H. hiemale because of its robust habit and lack of veil, however there are more orange color tones of the pileus; the spores are smaller and more dextrinoid than one would expect for H. alpinum and H. hiemale.
Geographic distribution
  • arrow_drop_downarrow_drop_upAdditional cited collections

Image gallery

Looking up available images for avellaneum

Data viewer

(No data)
(No data)