Amanita vladimirii Sevcikova, Hanss, sp. nov.
Creators: name: Ševčíková, Hana
name: Hanss, Jean-Michel
name: Moreau, Pierre-Arthur
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Amanitaceae
Amanita
Amanita vladimirii

description: Amanita vladimirii Ševčíková, Hanss & P.-A. Moreau sp. nov. Figs. 4, 5
MycoBank: MB837917
Etymology:—“ vladimirii ” honours the famous Czech mycologist Vladimír Antonín, collector of the holotype and two additional collections.
Diagnosis:—Differs from all other species of Amanita sect. Vaginatae by the unique combination of a thick, 3-layered universal membranous veil with predominant yellow-coloured hyphae in the middle and outer layers; a broadly umbonate, grey-coloured pileus; sub-spherical basidiospores, Q=1.0–1.1; an indistinct hymenopodium; thromboplerous hyphae abundant in the mediopellis; and an association with species of Fagaceae, or Pinaceae.
Holotype:— CZECH REPUBLIC. Javorníky Mts., Razula National Nature Reserve, Abieto -Fagetum, on soil under Fagus sp., alongside Abies sp. and Picea sp., 4 August 2016 leg. V. Antonín & D. Janda, BRNM 825828, GenBank/EMBL: MW208927 (ITS rDNA); MW208923 (LSU); MW208627 (tef 1-α).
Description:— Pileu s 48‒85 mm diam, up to 35 mm high, paraboloid or obtusely conical-campanulate, later applanate, 8‒17 mm long striate at margin, smooth, glabrous, slightly viscid when wet; greyish brown (7D‒ E2, 7 E‒F3) or greyish yellow (4B3–4) at centre; paler, brownish grey (7D2), yellowish grey (4B2–3), grey (7B1) or white to silvery grey (3A1–7A1) towards margin, becoming silvery metallic reflection with drying. Lamellae moderately crowded, L = 106–130, l = 0(–1), free, ventricose, up to 4.5 mm broad, white (1A1) to almost cream with white to concolorous edge not darkening with age or when dried. Stipe 110‒190 × 9–13 mm, cylindrical, slightly broadened towards base (13‒30 mm diam), white (1A1), sometimes slightly greyish after bruising, entirely finely whitely floccose to striped. Volva at base of stipe 41–60 mm high, up to ca. 30 mm in diam, 0.8–1.2 mm thick, usually type IV (Fraiture 1993), sometimes bilobate, firm, membranous, very finely tomentose and white on exterior, then yellowish on old specimens, ochre brownish (not rusty brown) where bruised, lustrous and white to greyish beige on interior. Context white, greyish under pileipellis, hollow in stipe. Smell indistinct. Taste not recorded. Spore print whitish.
Basidiospores globose to subglobose (8)8.5–11(11.5) × (6.7)8–10.1(10.5) µm, avl = 10.03; avw = 9.58; Q =1.00– 1.12(1.18); avQ = 1.046. Basidia (45)50–80 × (9)14–20 µm, tetrasporic, rarely bisporic, clavate to sometimes almost sphaeropedunculate, filled with dense oily content at maturity; sterigmata very thin (less than 1 µm wide), and up to 5–6 µm long. Lamellar trama 100–125 µm wide, colourless, reduced to a mediostratum composed of parallel, catenulate, inflated physaloidal cells 25–30 × 6–20(30) µm, occasionally with slender, 3–4 µm diam, cylindrical, hyphae, forming compact chains. Hymenopodium not differentiated. Subhymenium composed of hyphae 10–14 × 4–6 µm, mostly ramose (type I of Bas), (sub)cylindrical, rarely inflated or deformed, with very rare subcellular elements only at the base of mature basidia. Lamellar edge sterile, marginal cells (25)28–33(36) × 10–25 µm, slightly gelatinized, colourless, thin-walled, pyriform to ampullaceous. Pileipellis an ixocutis 400–600 µm wide; upper layer 100–200 µm wide, gelatinized, composed of hyphae 1.5–2.5 µm wide: lower layer faintly gelatinized, composed of dense parallel hyphae 2–3 µm wide, with thick, tortuous, refractive hyphae, dark in Congo Red, of thromboplerous type, becoming more numerous towards the context. The confluence zone with the context consists of the same, but less compact hyphae. Subpellis faintly differentiated, with similar but less compact hyphae than the deep suprapellis. Context of pileus thin, but not measurable, mainly composed of oval physaloidal elements 60‒100 × 10‒30 µm, mixed with narrow hyphae. Volva 400–1000 µm thick, distinctly 3-layered: outer layer about 75 µm thick, composed of parallel hyphae strongly twisted and entangled with transversally oriented hyphae 5–6(8) µm wide; intermediate layer composed of similar but less twisted, more or less intricate hyphae forming a firm structure; inner layer 150–200 µm thick, composed of sphaerocysts (28)30–70(90) × 25–60(63) µm, less frequently ovoid or broadly clavate physaloidal hyphae (57)60–130 × 20–30 µm (acrophysalids) and filamentous hyphae 4–9 µm wide. In collection BRNM 695616 the lower part of the universal veil has a thick (600 µm) inner stratum and thinner intermediate stratum. Clamps absent from all studied tissues.
Additional material examined:— CZECH REPUBLIC. Javorníky Mts., Razula National Nature Reserve, Abieto -Fagetum, under Fagus sylvatica, 13 August 2005, V. Antonín & D. Janda (BRNM! 695616, originally as A. pachyvolvata). Beskydy Mts., Salajka National Nature Reserve, on soil under Fagus sp., Abies sp. and Picea sp., 3 August 2016 V. Antonín & D. Janda (BRNM! 825829), GenBank/EMBL: MW208926 (ITS rDNA), MW208921 (LSU); MW208626 (tef 1-α). Vsetínské vrchy Mts., Karolinka, Smradlavá Nature Monument, Fagetum with Abies alba, under Fagus sp., 23 July 2018, H. Ševčíková (BRNM! 825830), GenBank/EMBL: MW208925 (ITS rDNA), MW208922 (LSU). FRANCE. Pas-de-Calais: Seninghem, Bois Large, mixed deciduous forest on acidic ground, dominated by Quercus robur, Fagus sylvatica and Carpinus betulus, with Betula alba and Corylus avellana, on clay soil, 3 October 2005, P.-A. Moreau & C. Platiau PAM05100302 (LIP! 0401726), GenBank/EMBL: MW208924 (ITS rDNA).
Habitat:—On soil in Fagetum to Abieto -Fagetum with Picea abies (Czech Republic), or Endymio-Fagetum (France).
Distribution:—So far only known from the Czech Republic and France.
description: Published as part of Ševčíková, Hana, Hanss, Jean-Michel & Moreau, Pierre-Arthur, 2021, Amanita vladimirii (Amanitaceae, Agaricales), a new European species in section Vaginatae, pp. 159-172 in Phytotaxa 482 (2) on pages 164-166, DOI: 10.11646/phytotaxa.482.2.4, http://zenodo.org/record/5418971