Cortinarius insanus Ballarà, Bidaud, Carteret & Huth sp. nov.

Mycobank MB#846488

Etymology: insanus = mad, crazy (Latin), refers to the sister species C. furiosus, the epithet of which bears the same meaning.

Diagnosis: Medium-sized bovinoid basidiomata, strongly hygrophanous and dehydrating in a Kuehneromyces mutabilis fashion with conspicuous radial strips or spots. Spores ellipsoid to broadly amygdaloid, 6.1– 7.1 –8.1 × 4– 4.4 –4.8 µm in size, moderately verrucose. Deciduous thermophilous woodlands of Europe, on calcareous soils. Differs from the sister species C. furiosus by slightly smaller spores less prominently ornamented and an average shorter and later fruiting period.

Type: SPAIN. Catalonia: Girona, Garrotxa, Vall d’en Bas, Joanetes, N42°07’19” E2°25’02”, 610 m asl, under Q. ilex on calcareous soil, 31 Oct. 2015, J. Ballarà, VAL _Myco1667! (isotype JB-8770-15, JB personal herbarium), ITS GenBank ON818537 .

Description (Fig. 3): Basidiomata medium sized. Pileus 30–60(–75) mm in diameter, convex with rounded and low umbo; margin first incurved, later extended and slightly serrulate, with persisting whitish veil remnants; surface hygrophanous, smooth or covered with silvery micaceous radial innate fibrills, brown, beige-brown, violet brown (Séguy 713, 702, 693), chestnut-brown (Cailleux R47), dark red-brown (Caill. T50), umbo distinctly darker, soon dehydrating in a K. mutabilis fashion with conspicuous radial strips or spots, pale beige brown, pale reddish brown (Ség. 715, 705, 704, 700), pinkish-grey (Caill. M71) to blackish in mature pilei due to necropigments (Ség. 681, 676). Lamellae moderately crowed, wide, emarginate or uncinate, brownish to rusty-ocre (Caill. R55, N55, N47), brown, dark brown (Ség. 693, 692); edges slightly paler, mustard brown with age. Stipe cylindrical to clavate-bulbose, sometimes rooting with white mycelial strands, (30–)40–60(–85) mm long x 7–10(–14) mm diameter at the apex, reaching 12–20(–30) mm diameter in the basal bulb; surface white then pale beige to sepia on the bulb, with universal veil copious towards the base, partial veil fugacious, not forming any ring zone. Context generally fibrous, marbled, pale ochraceous, brownish in the stipe cortex, darkening to KOH; taste and smell mild, sometimes of raddish or parsley, sometimes slightly earthy.

Basidiospores [6, 6, 201], 6.1–8.1 × 4.0–4.8 µm, M = 7.1 × 4.4 µm, intercarpic variation of M: 6.6–7.6 × 4.3–4.5 µm, Q = 1.42–1.78, Q m = 1.60, intercarpic variation of Q m: 1.53–1.68, subamygdaloid, densely verrucose, with warts of moderate size, mostly not distinctly visible in the outline of the spores. Reaction with Melzer’s reagent more or less “strongly dextrinoid” in most collections (Table 1 and Fig. 5). Basidia 25–37 × 8–11 µm, 4-spored, present on lamellar edge. Sterile elements present on lamellar edges, claviform, 20–34 × 7–9 µm. Pileipellis a cutis formed by a layer of clamped, more or less cylindrical hyphae, 4–8 µm wide, with scattered pale ochraceous incrusting wall pigments. Subcutis composed of short and irregularly-arranged, septate hyphae, 30–75 × 20–32 µm. Veil hyphae (remnants at pileus margin) 2–3 µm diam.

Habitat & distribution: Autumn, in thermophilous Quercus woodlands on calcareous soil, in association with Q. ilex in the Mediterranean, but also found at thermophilous sites in Germany.

Other studied material: FRANCE. Ardèche: Lagorce, Rocles, 200 m asl, under Q. ilex on calcareous soil, 5 Dec. 2018, G. Raffini & A. Bidaud, AB 18-12-219, ITS GenBank ON818531; Hérault: Bédarieux, Levas, under Q. ilex on calcareous soil, 23 Oct 2013, T.E. Brandrud, TEB 948-13, ITS GenBank ON818540; Isère: Leyrieu, under mixed deciduous trees on calcareous soil, 7 Oct. 2007, X. Carteret, XC 2007-75, ITS GenBank ON818541; Saône-et-Loire: Montceaux-Ragny, Bois des Brousaillons, 340 m asl, under Q. pubescens and Buxus sempervirens on calcareous soil, A. Bidaud & C. Gérard, 17 Nov. 2011, AB 11-11-343, ITS GenBank ON818530. GERMANY. Sachsen-Anhalt: Freyburg, NSG Tote Täler, under C. betulus and Quercus spp . on calcareous soil, 17 Oct. 2013, M. Huth, HM 17.10.2013, ITS GenBank ON818532; Sachsen-Anhalt: Freyburg, NSG Tote Täler, under C. betulus on calcareous soil, 17 Oct. 2016, M. Huth, HM2017-009 & HM2017-011, ITS GenBank ON818533 and ON818534, respectively. SPAIN. Mallorca: Escorca, Monastero de Lluc, 39°49´17.1´´ N / 2°53´31.8´´E, ca. 500 m asl, under Q. ilex and Pinus spp ., 11 Nov. 2018, F. Hampe & J. Kleine, JK Cort18111108, ITS GenBank ON818539; Catalonia: Girona, Garrotxa, Planes d’Hòstoles, Cogolls, N42°04’58» E2°32’18», 480 m asl, under Q. ilex on +/- calcareous soil, 24 Oct. 2015, J. Ballarà, JB-8727-15/ VAL_Myco1666!, ITS GenBank ON818536; Catalonia: Barcelona, Berguedà, Montmajor, Comarmada, N42°02’33” E1°44’09”, 885 m asl, under Q. ilex on calcareous soil, 19 Oct. 2014, J. Ballarà, JB-8487-14, ITS GenBank ON818535; Catalonia: Barcelona, Berguedà, Montmajor, Mare de Deu del Bosc, N42°02’33» E1°44’10», 880 m asl, under Q. ilex and Q. humilis on calcareous soil, 4 Nov. 2018, J. Ballarà, JB-9912-18, ITS GenBank ON818538.