Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima, 2022

Buyck, Bart, Eyssartier, Guillaume, Armada, François, Corrales, Adriana, Hembrom, Manoj Emanuel, Rossi, Walter, Bellanger, Jean-Michel, Das, Kanad, Dima, Bálint & Ghosh, Aniket, 2022, Fungal biodiversity profiles 111 - 120, Cryptogamie, Mycologie 20 (2), pp. 23-61 : 29-31

113. Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima , sp. nov.

( Figs 2 ; 5 ; 6 )

DIAGNOSIS. — Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima , sp. nov. can be distinguished from E. turci , which frequently occurs in similar habitats, by the finely roughened, innately fibrillose stipe, the absence of red staining at stipe base, and the absence of cheilocystidia.

HOLOTYPE. — France. Savoie , Bourg-Saint-Maurice, Arc 2000, secteur du lac Marlou, 2500 m alt., leg. F. Armada, 21.VIII.2018, holo-, LY ( FA 4277 ).

MYCOBANK. — MB 840118.

GENBANK. — MZ198884 (ITS holotype).

ETYMOLOGY. — Nigrus for black and flavescens for yellowing, referring to the colour and colour change of the pileus.

ADDITIONAL MATERIAL STUDIED. — France. Savoie, Peisey-Nancroix, secteur du col de la Chal, 2500 m alt., leg. F. & E. Armada, 17.VIII.2010, LY(FA 1726), ITS[ MZ198883 ].

DESCRIPTION

Pileus

9-22 mm, convex to plano-convex, with slightly inflexed margin, very variably shaped, sometimes umbilicate, with a small central umbo, or with irregular, undulating margin, not hygrophanous, not translucently striate, entirely very dark blackish brown to sepia brown at first, later on more yellow brown at margin, finally most of the pileus yellow brown with dark brownishblack centre; entirely rugose-tomentose to rimulose-fibrillose at first, breaking up in appressed squamules all over with age.

Lamellae

Rather distant, adnate-emarginate, thin or somewhat thick, ventricose, up to 3.5 mm broad, frequently intervenose, sordid white to greyish white, then sordid pinkish brown with an entire, thickened, concolorous edge.

Stipe

16-38 × 1.5-3.5 mm, equal, cylindrical, straight or curved, early fistulose, almost white when young, then beige-yellowish to pale yellow brown, minutely pruinose/punctate when young, glabrescent, never strictly polished but with fine, innate fibrils, base attenuate or slightly enlarged, slightly white tomentose, no reddening observed.

Context

Very thin, fragile, concolorous with surface, white inside, not reddening.

Odour

Weak or vaguely farinaceous.

Taste

None.

Basidiospores

(9)10.5-12.5 × (6.7)7.0-8.5(9) µm, heterodiametrical, irregularly 7-8(9) angled, sometimes almost nodulose.

Basidia

36-45 × 11.5-13 µm, 4-spored.

Cheilocystidia

Absent, lamella edge fertile.

Pileipellis

A cutis with transitions to a trichoderm, with clavate terminal elements, 30-90 × 13-24 µm. Pigment brown, intracellular.

Clamp-connections

Absent.

Habitat

In alpine zone, on mossy soil amongst Salix herbacea , Polygonum viviparum , and Alchemilla pentaphyllea .

Distribution

Known from two different localities in the French Alps.

NOTES

Entoloma nigroflavescens sp. nov. is a remarkable species with its dark, blackish brown basidiomata, which develop yellow tinges when maturing, and the fertile lamella edge without cystidia. In the ITS phylogeny it is a sister species to E. perasprellum , a recently described new species from the Alps, with a blue, polished stipe, reminiscent of E. asprellum (Dima et al. 2021). Entoloma nigroflavescens sp. nov. can be distinguished from E. turci which frequently occurs in similar habitats, by the finely roughened, innately fibrillose stipe, the absence of red staining at stipe base, and the absence of cheilocystidia.

Figures

FIG. 2. — Phylogenetic tree depicting the relationship of Entoloma aurantioalpinum Armada, Vila, Bellanger, Noordel., Krisai & Dima, sp. nov. and Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima, sp. nov. within subgen. Cyanula, clades /Sarcitulum and /Atrocoeruleum, respectively. The new species are highlighted in color rectangles. Newly generated sequences are in boldface. The analysis was inferred from nrDNA ITS sequences using PhyML 3.1 with the following settings: GTR+I+G model of evolution, gamma distribution of 10 rate categories, and tree topology search as SPR. Branch support was tested using the non-parametric, Shimodaira-Hasegawa version of the approximate likelihood-ratio test (SH-aLRT). PhyML SH-aLRT support values (>50) are indicated at the branches. Main clades within the subgenus are compressed. Clitopilus was chosen as outgroup. Bar indicates 0.05 expected change per site per branch.

FIG. 5. — Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima, sp. nov., habit in situ (from holotype). Photo: F. Armada.

FIG. 6. — Microstructures of Entoloma nigroflavescens Armada, Bellanger, Noordel. & Dima, sp. nov.: A, spores; B, lamella edge with basidia and basidioles; C, D, elements of pileipellis. Photos: F. Armada. Scale bars: A, 10 µm; B, D, 20 µm; C, 50 µm.