Hebeloma catalaunicum (Photo: C. Lavorato)

Taxonomy

Types: SPAIN: Girona, Mas Roures,Llagostera (Girona) (approx. 41.82°N, 2.89°E, alt. approx. 140 m a.s.l.) under Eucalyptus sp., 30 Dec. 1997, X. Llimona, J. Vila (JV-JVG971230A) (Holotype. herbarium acc. no. BR5020184132484, HJB11519).

• arrow_drop_downarrow_drop_upEtymology
  This species was for a long time only known from two locations within the Catalan province of Spain. Catalaunicus– from Catalonia.

• arrow_drop_downarrow_drop_upDiagnosis
  Hebeloma catalaunicum is morphologically similar to H. nanum and H. naviculosporum. The cheilocystidia of H. catalaunicum are as diversely and irregularly shaped as is typical for H. sect. Naviculospora with average apex width greater than 5 µm and average basal width greater than 6 µm. The spores are weakly ornamented and distinctly to strongly dextrinoid, with the perispore distinctly but not constantly loosening, average length at most 11 μm and average width at least 5.7 μm. Molecular data support H. catalaunicum as an independent species related to the above named species. To date, H. catalaunicum has only been found in the Mediterranean region.

Description

Description of Hebeloma catalaunicum based on 9 collections

• arrow_drop_downarrow_drop_upMacroscopic description
  Pileus: (20) 33–71 (90) mm diameter; shape convex, occasionally umbonate; characters occasionally hygrophanous or rugulose; margin characters often involute, smooth or sulcate, occasionally crenulate or eroded; viscosity tacky when moist; colour variation often unicolour, occasionally two color; colour at centre occasionally umber, ochraceous, honey, brownish olive or orange-brown.

  Lamellae: attachment usually emarginate, occasionally adnate; maximum depth 5–6 mm; number of complete lamellae 70–120; presence of tears absent; white fimbriate edge often present, occasionally weak, rarely absent.

  Cortina presence: no.

  Stipe: (20) 25–55 (70) x (6) 7–12 (14) {median} x (5) 6–11 (14) {basal} mm; stipe Q 3.1–5.8; base shape cylindrical, often tapering, rarely clavate; floccosity often fibrillose, occasionally pruinose, pruinose at apex, floccose or weakly floccose; rooting usually no, occasionally yes; thick rhizoids at base absent;

  Context: Texture firm; stipe interior often stuffed or hollow; stipe flesh discolouring variable; slenderness measure 2.1–6.3; smell occasionally raphanoid or odourless, rarely cocoa, earthy or strongly raphanoid; taste often mild or raphanoid where recorded.

  Spore deposit colour: Not recorded.

  Exsiccata characters: Not recorded.

• arrow_drop_downarrow_drop_upMicroscopic description
  Spores: shape amygdaloid; colour in microscope occasionally yellow, yellow pale or yellow brown; guttules often yes, occasionally no. papilla no; Spore Code: O2; P0 P1; (D2) D3.

  Basidia: (16) 19–39 x 5–8 (9) μm; ave. Q 3.3–4.7; spore arrangement 4 spored;

  Cheilocystidia: main shape clavate-lageniform or clavate-ventricose, often cylindrical, ventricose or gently clavate, occasionally clavate-stipitate or lageniform, rarely clavate; special features observed often irregular or grotesque, occasionally geniculate or septa, rarely conglutinate, many collapsed in exsiccata, rostrate or short; cheilocystidia ratios: A/M = 1.15–1.69; A/B = 0.82–1.13; B/M = 1.25–1.78.

  Pleurocystidia: none seen.

  Ixocutis: epicutis thickness (measured from exsiccata) up to 250 μm; ixocutis hyphae width up to 7 μm; ixocutis hyphae encrustation no; shape of trama elements beneath subcutis often hyphae thick, thickly sausage-shaped or thinly sausage-shaped up to 16 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
  Hebeloma catalaunicum's preferred habitat appears to be woodland or Mediterranean maquis with mossy soil and litter or soil and litter. Where only one possible associate was recorded, the most commonly recorded associate was Eucalyptus (75.0%) but Pinus (25.0%) were also recorded. In these cases the most commonly recorded families were Myrtaceae (75.0%) and Pinaceae (25.0%). We have additional records where Cistus (25.0%), Arbutus (25.0%), Quercus (25.0%) and Cedrus (12.5%) were recorded as possible associates, but in these cases a number of possible associates were mentioned. Overall the most commonly recorded families are Myrtaceae (62.5%), Pinaceae (50.0%), Cistaceae (25.0%), Ericaceae (25.0%) and Fagaceae (25.0%) The growth habit of our collections was occasionally caespitose, gregarious or scattered.

  According to our current collections, the species is found only in Europe. On the continent, collections have been found only in the mediterranean forests, woodlands & scrub WWF biome 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. (Tyrrhenian-Adriatic sclerophyllous and mixed forests (37.5%), Northeast Spain and Southern France Mediterranean forests (25.0%), Southwest Iberian Mediterranean sclerophyllous and mixed forests (25.0%) and Iberian sclerophyllous and semi-deciduous forests (12.5%) ecoregions). From collector information, it appears collections have been found in the 1.4 Forest – Temperate (66.7%) and 3.8 Shrubland – Mediterranean-type shrubby vegetation (33.3%) 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 Europe we have records from the Southwest (Spain, Italy and Portugal) and the Southeast (Italy). Specimens have been collected from 37.2°N to 44.2°N.

• arrow_drop_downarrow_drop_upMolecular results
  Hebeloma catalaunicum is very well supported by bootstrap in the five-locus analysis. This taxon forms a distinct clade in all nuclear loci used, but is very similar to H. nanum in the mitochondrial loci. The different topologies of the single locus trees do not cast doubt on the distinctness of H. catalaunicum. The results only imply we cannot resolve which of the two species of H. nanum and H. naviculosporum is its closest relative. We are not aware of any published ITS sequences that might belong to this species from outside Europe or of any European sequences from material other than those mentioned here.

• arrow_drop_downarrow_drop_upCommentary
  Hebeloma catalaunicum with its short, irregular cheilocystidia, often cylindrical but also clavate-lageniform or ventricose and numerous shapes in-between appears to fit well within H. sect. Naviculospora, which includes other species with such irregular cheilocystidia. Our molecular studies support the placement of this taxon. Unfortunately we do not have a picture of either of the collections of H. catalaunicum from Catalonia. On both occasions on which it was collected the forayer did not realise the significance of the collection. Indeed the collection from Collsacreu maresme-barcelona (MCVE 13641, lodged as H. pallidum) was a mixed collection, within which the larger part of the collection was H. subtortum. We do have a picture of the Italian collection. The amygdaloid spores, weakly ornamented (O2), with perispore at most somewhat loosening in a few spores (P0 or P1), at least 5.7 μm wide but less than 11 μm long and with both apex and base of cheilocystidia quite swollen (greater than 5.2 μm and 6 μm respectively), separate this taxon from other members of both H. sect. Scabrispora and H. sect. Naviculospora. If one is deceived by the cheilocystidium shape and tries to key this species out in H. sect. Theobromina, one arrives at a couplet (4) in which the choices are a Cistus associate or spores O3. One might choose the Cistus associate as the more likely option, but this would lead to H. erumpens which is a very different fungus. As discussed above, Hebeloma catalaunicum is currently only known from two locations in Catalonia within 35 km from each other and from Calabria (E. Grilli has recently made us aware of another collection from Sardinia). While it is certainly rare, it will probably be difficult to truly understand this taxon and its distribution until we have more collections.

Geographic distribution

Phenology

• arrow_drop_downarrow_drop_upAdditional cited collections

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