Hygrocybe rubroalba Picciola, Battistin & Vizzini, 2015

Vizzini, Alfredo, Picciola, Paolo, Battistin, Eliseo & Ercole, Enrico, 2015, Hygrocybe rubroalba (Hygrophoraceae, Agaricales), a new species of sect. Firmae from Brazil, Phytotaxa 226 (1), pp. 18-26 : 22

Hygrocybe rubroalba Picciola, Battistin & Vizzini , sp. nov. Figs. 3–4

Mycobank MB813563

Diagnosis:—It is distinguished from Hygrocybe martinicensis by a scarlet red, purplish red pileus and stipe, lemon yellow context, the absence of cheilocystidia, and different ITS and LSU sequences.

Type:— BRAZIL, Paraná: Curitiba, Campina Grande do Sul, 25°18’21’’ south, 49°03’18’’ west, broad-leaved trees and Araucaria angustifolia , 980 m alt., 07 January 2014, P. Picciola, MCVE 28634 (Holotype, MCVE!).

Etymology:—from Latin rubrus (red) and albus (white), referring to the red pileus surface and the white lamellae.

Pileus 10–43 mm broad, convex to plane, then slightly depressed or (sub)umbilicate, not or hardly hygrophanous when moist ( Fig. 3a, c ), bright red, scarlet red, purplish red (Spectrum Red, Scarlet-Red, Plate I; Tyrian Rose, Plate XII; Spinel Red, Plate XXVI), violaceous purplish at margin (Light Phlox Purple, Violet-Purple, Purple, Plate XI), soon spotted ivory to orange-yellow (Bittersweet Orange, Plate II; Mikado Orange, Orange, Plate III; Buff-Yellow, Plate IV); on drying ( Fig. 3b, d ) it fades to light orange-red (Mikado Orange, Cadmium Orange, Plate III) with evident purplish hues (Hermosa Pink, Plate I; Phlox Pink, Light Phlox Purple, Purple, Plate XI). Surface dry, smooth, glabrous, sometimes slightly rugulose (under 10x lens); margin inflexed, exceeding lamellae, not translucently striate, entire to slightly wavy-lobed. Lamellae distant (L = 20–30), with many lamellulae of different length [l = 1–2(3)], emarginate to adnate or emarginate with decurrent tooth, up to 4 mm broad, thick, sometimes intervenose at the base, pure white but with purplish tinges at the base and towards the pileus margin; edge even to undulate, concolorous. Stipe 33–60 × 3–10 mm, central or slightly eccentric, straight to curved or flexuose, equal or tapering upwards, cylindrical or compressed, dry, finely fibrillose, fistulose to broadly fistulose, entirely bright red at first, then progressively orange to lemon yellow (Light Orange-Yellow, Plate III; Lemon Yellow, Plate IV) starting from apex and base. Context lemon yellow in the stipe; odour none, taste bitterish. Spore print not obtained.

Macrospores (11.0) 12.0– 13.3 –15.0 (16.0) × (6.7) 7.0– 8.0 – 9.0 (10) μm, Q = (1.4) 1.5 – 1.7 –1.9 (2.0) (n = 55) ellipsoid-oblong to oblong, smooth, thin-walled, opaque to monoguttulate. Microspores (6.0) 6.1– 7.1 –8.0 (9.0) × (3.0) 4.0– 4. 4 –5.3 (7.0) μm, Q = (1.2) 1.3– 1.6 – 1.8 (2.0) (n = 40), mainly ellipsoid, smooth, thin-walled, usually with one guttule. Macrobasidia 60–80 × 10–15 μm, clavate, slender, mainly 4-spored but also 2-spored; sterigmata up to 10 μm long. Microbasidia 35–55 × 5–8 μm, clavate, slender, 4-spored but also 2-spored; sterigmata up to 8 μm long. Hymenial cystidia absent. Hymenophoral trama (sub)regular, consisting of hyphae 21–92 μm long and 6–14 μm wide. Pileipellis as a cutis of sometimes ascending, repent and radially arranged 3–5 (7) μm wide hyphae. Pileus trama made up of interwoven, 45–98 × 9–22 μm cylindrical hyphae. Pigment parietal, hardly visible. Stipitipellis as a cutis of cylindrical, 50–67 × 3.3–9 μm hyphae. Stipe trama consisting of allantoid, 45–90 × (9) 12 14.5–24 μm hyphae. Clamp-connections present in all tissues.

Habit, habitat and known distribution:—terrestrial, fasciculate to gregarious, in a forest consisting of broad-leaved trees and Araucaria angustifolia (Bertol.) Kuntze. So far known only from Brazil.

Additional collection examined:— Brazil, Paraná: Curitiba, Campina Grande do Sul, 25°18’21’’ south, 49°03’18’’ west, from the same site as the holotype, broad-leaved trees and Araucaria angustifolia , 980 m alt., 31 December 2013, P. Picciola, TO AV31122013f (TO!).

Figures

FIGURE 3. Hygrocybe rubroalba. Basidiomata. a, c Basidiomata in moist condition (MCVE 28634, holotype). b, d Basidiomata in dry conditions (TO AV31122013f). Scale bars: 20 mm. Photos by P. Picciola.

FIGURE 4. Hygrocybe rubroalba. Microscopic features (from MCVE 28634, holotype). a. Macro and microbasidia. b. Immature macrobasidia. c. Immature microbasidia. d. Macro- and microspores. e. Pileipellis. f. Hyphae of the hymenophoral trama. Scale bars: a–d = 10 μm; e–f = 20 μm. Drawings by P. Picciola.