Hebeloma ammophilum (Photo: E. Larsson)

Taxonomy

Types: HUNGARY: Between Orkeny and Tatarszentgyorgy (approx. 47.1°N, 19.38°E, alt. approx. 120 m a.s.l.) on bare, sandy soil in sandhill under Populus sp., 8 Nov. 1975, M. Babos, A. Friesz, det: G. Bohus (Holotype. herbarium acc. no. BP 56.934, HJB1000051).

• arrow_drop_downarrow_drop_upEtymology
  From ammophilus– meaning sand loving.

• arrow_drop_downarrow_drop_upOriginal diagnosis
  Pileus 2–6 cm., primum convexus, deinde expansus, Hebeloma-brunneus, ochraceo-brunneus, interdum in margine pallidus, viscosus, cum sabulo toto obtectus. Lamellae 4–8 mm latae, siccae, ex aquosocremeae argillaceae, argillaceo-ferruginascentes, sicco ± brunnea, adnatae-emarginatae, non raro ventricosae, cum acie pallido. – Stipes 3–6 x 0.5–1 cm, aequalis vel inferne incrassatus, interdum inferne tenuiescens, non raro curvus, albus, albidus, tactu ochraceus, sericeus, sub lamellis farinosus. Caro albida, alba. Odor nullus vel vix raphanaceus. Sapor exiguous. Sporae magnae, 13–16(–17.5) x 7–8.5(–9.5) μm, amygdaliformes, interdum ventricosae, non raro in papillam elongatae, dense et insigniter punctatae-verruculosae, cum ectosporio non-vel haud decollatae, ochraceo-brunneolae. Cheilocystidiae claviformes, 33–50 x 8–17 μm. In sabulo vasto, primitus hypogaeus.

• arrow_drop_downarrow_drop_upEnglish translation
  Pileus 2–6 cm, at first convex then expanding, Hebeloma-brown, ochre-brown, sometimes with paler margin, viscid, entirely covered with sand. Lamellae 4–8 mm broad, dry, watery-cream-coloured at first then clay-coloured to rusty brown, more or less brown in dry state, adnate-emarginate, not rarely ventricose, with paler edge. Stipe 3–6 × 0.5–1 cm, equal or broadened towards base, sometimes narrowing towards base, not rarely curved, white or whitish, turning ochre when handled, shiny, under lamellae pruinose. Context white. Smell none or slightly raphanoid. Taste indistinct. Spores large, 13–16(–17.5) × 7–8.5(–9.5) μm, amygdaloid, sometimes ventricose, not rarely with elongated papilla, densely and markedly punctate, with loosening epispore or not, ochre-brown. Cheilocystidia claviform, 33–50 × 8–17 μm. In bare sand, first hypogeous.

Description

Description of Hebeloma ammophilum based on 14 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (20) 40–44 (60) mm diameter; shape convex; characters Not recorded; margin characters involute, often crenulate or smooth; viscosity tacky when moist; colour variation two color; colour at centre often ochraceous or dark pinkish buff.

  Lamellae: attachment emarginate; maximum depth up to 8 mm; number of complete lamellae 53–68; presence of tears often absent or visible with x10 lens; white fimbriate edge often present, occasionally absent.

  Cortina presence: no.

  Stipe: (30) 45–52 (65) x (5) 7–8 (10) {median} x (5) 7 (10) {basal} mm; stipe Q 5.7–6.5; base shape often cylindrical or tapering, occasionally clavate or sand bulb; floccosity often fibrillose, floccose, floccose at apex or pruinose at apex; rooting variable; thick rhizoids at base absent;

  Context: Texture firm; stipe interior hollow or stuffed; stipe flesh discolouring no; slenderness measure 7.1–7.5; smell often odourless, occasionally weakly raphanoid; taste Not recorded.

  Spore deposit colour: Not recorded.

  Exsiccata characters: Not recorded.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid, often limoniform; colour in microscope often brown, occasionally yellow brown, brown pale or yellow; guttules often no, occasionally yes. papilla often yes, occasionally very strongly; Spore Code: O2 O3; P1 (P2); (D2) D3.

  Basidia: 31–42 x 7–10 μm; ave. Q 3.4–4.2; spore arrangement 4 spored;

  Cheilocystidia: main shape clavate-lageniform or clavate-ventricose, occasionally gently clavate, rarely clavate, clavate-stipitate or cylindrical; special features observed often apical thickening, median thickening or septa, occasionally clamped septa, rarely bifurcate or many collapsed in exsiccata; cheilocystidia ratios: A/M = 1.44–1.85; A/B = 0.74–1.26; B/M = 1.36–1.94.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 200 μm; ixocutis hyphae width up to 5 μm; ixocutis hyphae encrustation yes; shape of trama elements beneath subcutis thickly sausage-shaped up to 15 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 ammophilum's preferred habitat appears to be sandhill or coastal sandhill with sandy soil, bare, sandy soil or mossy, sandy soil. Where only one possible associate was recorded, the most commonly recorded associate was Populus (66.7%) but Salix (16.7%) and Pinus (16.7%) were also recorded. In these cases the most commonly recorded families were Salicaceae (83.3%) and Pinaceae (16.7%). We have additional records where Quercus 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 (88.9%), Pinaceae (33.3%) and Fagaceae (11.1%) The growth habit of our collections was often gregarious and occasionally 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. unknown biome (38.5%), temperate broadleaf & mixed forests (38.5%) and mediterranean forests, woodlands & scrub (23.1%), specifically including the ecoregions: Unknown region (38.5%), Po Basin mixed forests (23.1%), Northeast Spain and Southern France Mediterranean forests (15.4%) and Pannonian mixed forests (15.4%). From collector information, it appears collections have been found in the 1.4 Forest – Temperate (50.0%) and 13.3 Coastal Sand Dunes (50.0%) 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 Centre (Hungary) and the Southwest (France). Specimens have been collected from 43.6°N to 47.1°N.

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma ammophilum is monophyletic and well supported in the ITS, V6 and V9 results and also in the five and six-locus results. Three of the four collections were too old to amplify single copy genes, but the data from the one more recent collection fully support the distinctiveness of H. ammophilum. We obtained the ITS of the holotype of the species. There are to date no other ITS sequences published from Europe or elsewhere that are likely to belong to H. ammophilum.

• arrow_drop_downarrow_drop_upCommentary
  Given the shape of its cheilocystidia, H. ammophilum clearly belongs to H. sect. Denudata. This species has most likely not been included in the intercompatibility tests of Aanen & Kuyper (1999). The dextrinoid spores, at most P2, together with the cheilocystidium ratio B/M on ave. greater than 1.35, puts it within H. subsect. Clepsydroida. The average spore width (> 6.5 μm), spore length (> 12.5 μm) and average width of cheilocystidium apex (> 8 μm) distinguish this taxon from other members of this subsection. In the past this species appears to have been confused with H. vaccinum and H. populinum. Although the latter species also occurs with Salicaceae, we have no records of it being collected in bare sand, and macroscopically it is quite different; microscopically, it is similar but the perispore of H. ammophilum is not as strongly nor as consistently loosening and the spore ornamentation does not have such a ‘spiny’ appearance. With regard to H. vaccinum, also in H. subsect. Clepsydroida, this species also often occurs on bare sand, but it is rather smaller and has average width of cheilocystidium apex at most 8 μm. Hebeloma ammophilum is certainly rare and, until we have more collections, it is difficult to be precise about its species delimitation.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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