Hebeloma velatum (Photo: H. J. Beker)

Taxonomy

Basionym:
Hebeloma colvinii var. velatum Peck [as "colvini"], Ann. Rep. Reg. N.Y. St. Mus. Nat. Hist. 48: 117 (1897) ["1896"]

Types: UNITED STATES: New York: Rouses Point (approx. 44.99°N, 73.36°W, alt. approx. 35 m a.s.l.) on gravelly soil under Populus monilifera, Sep. 1895, C.H. Peck (Holotype. herbarium acc. no. NYS-F-003339, HJB1000092).

Heterotypic synonyms:

• Hebeloma dunense L. Corb. & R. Heim, Mém. Soc. Sci. Nat. Math. Cherbourg 40: 166 (1929)
• Hebeloma aprile Romagn., Sydowia 36: 255 (1947) ["1983"]
• Hebeloma claviceps f. nigrescens Killerm., Denkschriften der Bayerischen Botanischen Gesellschaft in Regensburg 16: 97 (1925)
• Hebeloma collariatum Bruchet, Bull. Mens. Soc. Linn. Lyon 39, supplement 6: 125 (1970)
• Hebeloma collariatum f. aprile (Romagn.) Esteve-Rav., Boletín de la Sociedad Micológia de Madrid 20: 143 (1995)
• Hebeloma collariatum f. psammicola (Bohus) Bohus, Documents mycologiques 25 (98-100): 86 (1995)
• Hebeloma psammicola Bohus [as "psammocolum"], Ann. Hist.-Nat. Mus. Natl. Hung. 70: 103 (1978)
• Hebeloma remyi Bruchet ex Quadr., Mycol. Helv. 3 (2): 193 (1989) ["1988"]
• Hebeloma subcaespitosum Bon, Documents mycologiques 8 (29): 35 (1978)
• Hebeloma subcaespitosum var. psammicola (Bohus) Bohus [as “psammocolum”], Studia Botanica Hungarica 16: 42 (1983) ["1982"]
• Hebeloma versipelle f. alpinum Citerin [as “inédite”], Bulletin trimestriel de la Fédération Mycologique Dauphiné-Savoie 128: 27 (1993)
• Hebeloma xerophilum Rudn.-Jez. [as “xerophila”], Acta Mycol. 3: 183 (1967)
• Hebeloma bicoloratum var. coloradense A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 64 (1983)
• Hebeloma naucorioides A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 171 (1983)
• Hebeloma pitkinense A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 156 (1983)
• Hebeloma subfastigiatum A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 180 (1983)
• Hebeloma wellsiae A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 34 (1983)
• Hebelomatis dunense (L. Corb. & R. Heim) Locq., Flore Mycologique Vol III - Text. Cortinariales A: 130 (1979) ["1977"]
• Hebeloma bingolense I. Acar, Dizkirici, Kalmer & Y. Uzun, Nova Hedwigia 114 (1-2): 61 (2022)

• arrow_drop_downarrow_drop_upEtymology
  From velatus (Latin), meaning covered, partially concealed from view, presumably referring to the presence of the veil.

• arrow_drop_downarrow_drop_upDiagnosis
  Scattered or caespitose; pileus convex, plane or even slightly depressed, brittle, obtuse or umbonate, adorned with a tomentose veil, which either disappears with age or persists and makes the pileus obscurely floccose-scaly or its margin silky or floccose; lamellae rather close, subventricose, adnexed; stem equal, brittle, hollow, silky-fibrillose and often somewhat floccose-squamose toward the base, sometimes annulate with a thick, soft, cottony ring; spores subelliptical, even, .0004 to .0005 inch long, .00024 to .0003 broad [10.2-12.7 x 6.1-7.6 µm]. Pileus 1 to 2.5 inches broad [25-64 mm]; stem 1.5 to 2.5 inches long [38-64 mm], 2 to 3 lines thick [5.1-7.6 mm]. Gravelly ground under cottonwood trees, Populus monilifera. Rouses Point. September. Three forms were found growing together. The first and most abundant has the mature pileus glabrous or slightly silky on the margin only; the second has the grayish or reddish-gray pileus adorned with appressed floccose scales; the third differs from the second only in the dark chestnut color of the pileus. The veil is grayish-white and when well developed it adheres partly in fragments to the margin of the pileus and partly as an annulus to the stem. The cavity of the stem is very small. A slight odor like that of radishes is perceptible. The species belongs to the section Indusiati. The variety differs from the type especially in its strongly developed veil.

Description

Description of Hebeloma velatum based on 432 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (1) 8–42 (70) mm diameter; shape occasionally convex or umbonate, rarely broadly umbonate, papillate, weakly umbonate, strongly umbonate or umbilicate; characters occasionally remains of universal veil, rarely hygrophanous, pubescent, rimulose, rugulose or spotting; margin characters often smooth, rarely involute, fibrillose, scalloped, serrate, eroded, appendiculate, reflexed or sulcate; viscosity tacky when moist; colour variation often unicolour or two color; colour at centre occasionally yellowish brown or umber, rarely sepia, dark brick, clay-buff, ochraceous, brownish olive, cinnamon, fuscous, greyish brown, orange-brown, dark fawn or dark pinkish buff.

  Lamellae: attachment often emarginate, occasionally adnate, rarely adnexed, decurrent or decurrent tooth; maximum depth 1–9 mm; number of complete lamellae 23–49; presence of tears usually absent, rarely visible with x10 lens or visible with naked eye; white fimbriate edge often present, occasionally weak, rarely absent.

  Cortina presence: yes.

  Stipe: (0) 12–54 (80) x (0) 2–6 (12) {median} x (0) 1–7 (12) {basal} mm; stipe Q 2.3–20.0; base shape usually cylindrical, occasionally clavate, rarely sand bulb or tapering; floccosity often fibrillose, occasionally fibrous or pruinose at apex, rarely floccose, floccose at apex, none, pruinose or tomentose; rooting usually no, rarely yes or weak; thick rhizoids at base usually absent, rarely present;

  Context: Texture firm; stipe interior usually hollow, occasionally stuffed, rarely superior wick; stipe flesh discolouring usually yes, rarely no, weak or very strongly; slenderness measure 2.4–54.0; smell occasionally odourless, raphanoid or cocoa, rarely weakly raphanoid or strongly raphanoid; taste occasionally mild, raphanoid or bitter, rarely none, weakly raphanoid, weakly bitter or strongly raphanoid where recorded.

  Spore deposit colour: often brownish olive, occasionally umber, rarely yellowish brown, sepia, greyish brown or fuscous.

  Exsiccata characters: rarely dark, lamellae blackening, pale or shiny.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape usually ellipsoid, occasionally ovoid or amygdaloid, rarely cylindrical, reniform, fusoid, lacrymoid, limoniform or navicular; colour in microscope occasionally yellow brown or brown yellow, rarely brown, brown pale, yellow, yellow pale or very pale; guttules variable occasionally weak. papilla usually no, rarely yes; Spore Code: O1 O2; P0; D0 D1.

  Basidia: (18) 20–34 (35) x (5) 6–10 μm; ave. Q 2.8–4.2; spore arrangement 4 spored;

  Cheilocystidia: main shape usually lageniform or ventricose, rarely clavate, cylindrical, subcapitate or clavate-lageniform or clavate-ventricose; special features observed occasionally septa, rarely many collapsed in exsiccata, apical thickening, yellow contents, bifurcate, basal thickening, clamped septa, slender, geniculate, median thickening, short, conglutinate, distorted, grotesque, large, mucous, sparse or wide upper half; cheilocystidia ratios: A/M = 0.82–1.43; A/B = 0.42–0.89; B/M = 1.40–2.14.

  Pleurocystidia: usually none seen, rarely only close to lamella edge.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 125 μm; ixocutis hyphae width up to 8 μm; ixocutis hyphae encrustation variable; shape of trama elements beneath subcutis occasionally polygonal, thickly sausage-shaped or thinly sausage-shaped, rarely angular, ellipsoid, isodiametric, ovate or spherical up to 25 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma velatum's preferred habitat appears to be arctic tundra. Where only one possible associate was recorded, the most commonly recorded associate was Salix (85.9%) but Populus (6.3%), Dryas (3.2%) and Picea (1.4%) were also recorded. In these cases the most commonly recorded family was Salicaceae (92.3%). We have additional records where Betula (2.6%), Alnus (2.3%), Pinus (2.0%), Polygonum (1.4%) and Quercus (1.2%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Salicaceae (91.9%), Rosaceae (10.1%) and Pinaceae (5.2%) The growth habit of our collections was often scattered and rarely solitary, gregarious, caespitose or connate.

  According to our current data, the species is found on multiple continents with collections found in Europe (59.3%), Northern America (35.2%) and Temperate Asia (5.6%). 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. tundra (31.3%), temperate broadleaf & mixed forests (27.5%), temperate conifer forests (14.9%) and unknown biome (14.7%), specifically including the ecoregions: Unknown region (14.7%), European Atlantic mixed forests (12.5%), Alps conifer and mixed forests (10.1%) and Russian Arctic desert (10.1%). From collector information, it appears collections have been found in the 4.1 Grassland – Tundra (43.7%), 5.11 Wetlands (inland) – Alpine wetlands (inc. temporary waters from snowmelt) (14.9%) and 13.3 Coastal Sand Dunes (13.4%) 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 Europe we have records from the North (Svalbard, Wales, Norway, England, Denmark, Sweden, Iceland and Faroe Islands), the Centre (Belgium, Switzerland, Poland, Germany and Hungary), the Southwest (France and Spain) and the Southeast (Italy, North Macedonia and Romania). Specimens have been collected from 41.0°N to 79.1°N.

  Within Northern America we have records from Subarctic America (Nunavut, Greenland, Alaska, Northwest Territories and Yukon), Northwestern U.S.A. (Colorado, Wyoming and Washington), Eastern Canada (Quebec, Newfoundland and Labrador and Ontario), Western Canada (Manitoba, Alberta and Saskatchewan), Northeastern U.S.A. (Michigan and New York), Southwestern U.S.A. (California) and North-central U.S.A. (Minnesota).

  Within Temperate Asia we have records from Russian Far East (Chukotka and Sakha), Caucasus (Adygea and Georgia), Western Asia (Turkey) and Siberia (Krasnoyarsk).

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma velatum belongs in H. sect. Hebeloma owing to the mainly ventricose cheilocystidia and the elliptically shaped spores. Within this section, the relatively large elliptical spores and the persisting veil, together with the non-alpine, non-arctic habitat, suggest what we have so far been referring to as Hebeloma dunense. This is supported by ITS data. The publication of the name Hebeloma velatum predates the publication of the name H. dunense. In Beker et al. (2016) 1501 it was argued that H. dunense was conspecific with H. collariatum, and that there were also a number of other synonyms but that none was sufficiently well-established to warrant a conservation proposal. Since that publication, the name H. dunense has come into widespread use and as of the time of writing (Apr, 9 2021), Mycoportal has 48 records of H. dunense and none of H. velatum, and GBIF has 190 records of H. dunense vs. one of H. velatum (and nine of H. velatum Velen.) and still 94 of H. collariatum). Google (May, 6 2021) indicated over 2000 results for H. dunense from a name search, but less than 800 for H. velatum. Despite this, we feel that the name Hebeloma velatum, which does have priority, should take precedence for this taxon. Sequences from types of species synonymized with H. velatum (and formerly with H. dunense) form an unsupported clade within a clade that also includes sequences of H. alpinicola. Morphologically these two species are well separated, with H. velatum having significantly larger spores than H. alpinicola (av. 10.0–12.4 × 6.0–7.3 μm in H. velatum vs. 8.5–10.6 × 5.1–6.2 μm in H. alpinicola). Beker et al. (2016) indicated that H. velatum is not monophyletic in the ITS. At the time, the authors mentioned that it is mixed with H. mesophaeum. We are now aware that it is rather H. alpinicola, not recognized then, with which it is clustering. According to Beker et al. (2016), H. velatum (as H. dunense) receives molecular support using the loci rpb2 and tef1.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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