Hebeloma colvinii (Photo: H. Knudsen)

Taxonomy

Basionym:
Agaricus colvinii Peck [as "Agaricus (Hebeloma) colvini"], Ann. Rep. N.Y. St. Mus. nat. Hist. 28: 49 (1876) ["1875"]

Types: UNITED STATES: New York: sand hills, West Albany (approx. 43.0975°N, 73.9738°W, alt. approx. 390 m a.s.l.) on sandy soil in sandhill, Oct. 1874, V. Colvin, det: C.H. Peck (Lectotype. herbarium acc. no. NYS-F-000813.1, HJB1000269). Lectotype designated by Eberhardt et al., Mycologia 114 (2): (2022) page 351 (MBT10000877).

• arrow_drop_downarrow_drop_upType notes
  The holotype is a mixed collection: one part (NYS-F-000813.2) has whitish small, pip-shaped spores and does not match the protologue; the other part (NYS-F-000813.1) is here designated as lectotype. It has large, yellowish brown, elliptical spores and matches closely the description given in the protologue. Llectotype designated was NYS-F-000813.1 [p.p.]. GenBank: ITS = MN017797.

Heterotypic synonyms:

• Hebeloma affine A.H. Sm., V.S. Evenson & Mitchel, The Veiled Species of Hebeloma in the Western United States: 162 (1983)

Homotypic synonyms:

• Derminus colvinii (Peck) Henn. [as "colvini"], Hymenomycetineae: 243 (1898)

• arrow_drop_downarrow_drop_upEtymology
  In honour of its discoverer: Mr V. Colvin.

• arrow_drop_downarrow_drop_upDiagnosis
  Pileus fleshy, convex or expanded, sometimes gibbous or broadly umbonate, rarely centrally depressed, glabrous grayish or alutaceous inclining to pale ochre; lamellae close, broad, emarginate or rounded behind, whitish or pallid becoming brownish; stem flexuous, silky-fibrillose, stuffed or hollow, solid toward the base, whitish; spores subelliptical, .0004'-.0005' long [10.2-12.7 um]. Plant 2'-4' high [50.8-101.6 mm], pileus 1'-3' broad [25.4-76.2 mm], stem l"-3" thick [2.5-7.6 mm]. Sand hills near West Albany. October. This interesting species is dedicated to Mr. V. Colvin, to whom is due the credit of its discovery. Its habitat is peculiar, being the clear drifting sand of the plains west of Albany. The mycelium binds the sand together in a mass which adheres to the base of the stem. A cricket was observed feeding upon the pileus of a small specimen.

Description

Description of Hebeloma colvinii based on 12 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (13) 22–48 (75) mm diameter; shape usually convex, rarely umbilicate, umbonate or broadly umbonate; characters remains of universal veil, often pubescent; margin characters often appendiculate, occasionally eroded, involute, reflexed or wavy; viscosity tacky when moist; colour variation often unicolour or two color; colour at centre often sepia or orange-brown.

  Lamellae: attachment often adnexed or emarginate, rarely adnate; maximum depth up to 5 mm; number of complete lamellae 30–58; presence of tears absent; white fimbriate edge often present, occasionally weak, rarely absent.

  Cortina presence: yes.

  Stipe: (28) 41–67 (100) x (2) 4–8 (11) {median} x (2) 4–7 (10) {basal} mm; stipe Q 4.6–20.0; base shape often cylindrical or sand bulb; floccosity often fibrillose or pruinose at apex, rarely velute; rooting usually no, occasionally yes; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often hollow or stuffed; stipe flesh discolouring often yes, occasionally no; slenderness measure 7.7–28.9; smell often odourless, occasionally weakly raphanoid; taste often mild, occasionally strongly raphanoid or weakly raphanoid where recorded.

  Spore deposit colour: Not recorded.

  Exsiccata characters: Not recorded.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape ellipsoid, usually ovoid, occasionally amygdaloid; colour in microscope usually yellow brown, occasionally grey yellow or yellow; guttules usually no, occasionally yes. papilla no; Spore Code: O1; P0; D1 (D2).

  Basidia: 25–44 (47) x 7–11 μm; ave. Q 3.0–4.2; spore arrangement 4 spored;

  Cheilocystidia: main shape ventricose, usually lageniform, occasionally cylindrical, clavate-lageniform or clavate-ventricose or utriform, rarely balloon-shaped, clavate-stipitate or pyriform; special features observed occasionally apical thickening, septa, many collapsed in exsiccata, basal thickening, irregular, plaques or thick content in neck, rarely large, short, uniform or yellow contents; cheilocystidia ratios: A/M = 0.90–1.26; A/B = 0.46–0.77; B/M = 1.22–2.45.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 120 μm; ixocutis hyphae width up to 10 μm; ixocutis hyphae encrustation yes; shape of trama elements beneath subcutis occasionally cylindrical, ellipsoid, isodiametric or thickly sausage-shaped up to 16 μm wide.

  Caulocystidia: Similar to cheilocystidia but larger, up to 130 μm.

• arrow_drop_downarrow_drop_upSpore measurements

• arrow_drop_downarrow_drop_upCheilocystidia measurements

• arrow_drop_downarrow_drop_upHabitat and distribution
  Hebeloma colvinii's preferred habitat appears to be dune with sandy soil or boggy, sandy soil. Where only one possible associate was recorded, the most commonly recorded associate was Salix (80.0%) but Arctostaphylos (10.0%) and Abies (10.0%) were also recorded. In these cases the most commonly recorded families were Salicaceae (80.0%), Ericaceae (10.0%) and Pinaceae (10.0%). 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 Salicaceae (81.8%), Pinaceae (18.2%) and Ericaceae (9.1%) The growth habit of our collections was scattered.

  According to our current collections, the species is found only in Northern America. 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. temperate broadleaf & mixed forests (58.3%) and tundra (33.3%), specifically including the ecoregions: Kalaallit Nunaat Arctic steppe (33.3%) and Eastern Great Lakes lowland forests (33.3%). From collector information, it appears collections have been found in the 13.3 Coastal Sand Dunes (72.7%) and 5.10 Wetlands (inland) – Tundra wetlands (inc. pools and temporary waters from snowmelt) (27.3%) 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 Northern America we have records from Subarctic America (Greenland), Eastern Canada (Ontario) and Northeastern U.S.A. (New York and Michigan).

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma colvinii was originally described as “Agaricus colvini” (Peck 1875). The name is currently not in use, e.g. there are no records on Mushroom Observer (https://mushroomobserver.org/, accessed 23 Sept 2020) and while Mycoportal (https://mycoportal.org/portal/collections/list.php, accessed 2 Dec 2020) has 63 records, the most recent is from 1972. The identification of the Greenland collections is supported by unpublished studies of type material. It appears that exposed expanses of sandy soil are the characteristic habitat for the species, which is morphologically similar to a number of species of the difficult group around H. dunense and H. mesophaeum. Hebeloma colvinii can be recognized by its large ellipsoid spores, reminiscent of Hebeloma psammophilum, which is currently known only from western Europe (Beker et al. 2016).

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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