Pleurotus magnificus Rick, Brotéria, Rev.

Bittencourt, Felipe, Drewinski, Mariana De Paula, Jr, Nelson Menolli & Drechsler-Santos, Elisandro Ricardo, 2024, Rare Pleurotus species with veiled basidiomata from the Neotropics: neotypification of Pleurotus magnificus and epityfication of Pleurotus rickii, Phytotaxa 672 (1), pp. 30-48 : 36-38

Pleurotus magnificus Rick, Brotéria, Rev. scienc. nat. Colleg. S. Fiel 5: 22 (1906). Figs 3 , 4

Neotype (designated here, MBT10022153):— BRAZIL. Santa Catarina: Três Barras, Floresta Nacional de Três Barras , 824 m a.s.l., 26°12’59’’S, 50°18’07’’W, yellow basidioma on fallen trunk with ca. 35 cm diameter, 2 June 2014, F. Bittencourt 134 ( FURB 44086 !).

Specimens examined:— BRAZIL. Paraná: Guarapuava, Parque Municipal das Araucárias, 23 February 2018, M.P. Drewinski MPD186 ( SP 512760 ) ; Jordão, Casa dos Drewinski, 12 February 2020, M.P. Drewinski MPD635 ( SP 512761 ). Santa Catarina: Painel, Pedras Brancas , next to Rio Caveiras , 27°51’54’’S, 50°11’59’’W, 8 May 2018, F. Bittencourt 1078 ( FLOR 79344 ) ; Três Barras, Floresta Nacional de Três Barras, 824 m a.s.l., 26°12’59’’S, 50°18’07’’W, yellow basidioma on fallen trunk with ca. 35 cm diameter, 2 June 2014, F. Bittencourt 134 ( FURB 44086 ). São Paulo: São Bento do Sapucaí, Restaurante Entrevillas , 20 April 2022, Marcelo Sulzbacher leg. N. Menolli Jr. NMJ443 (FIFUNGI 393). Rio Grande do Sul: Canela, on dead wood, 21 April 2018, J.M. Timm 46/18 ( FLOR 79343 ) ; São Leopoldo , in pino, 1908, J. Rick ( FH 00543855 ) [photograph] ; unknown location, J. Rick s/n, 27584 ( BPI 740091 [photograph!]) .

Description:— Basidiomata gregarious, scattered to caespitose ( Fig. 3A ). Pileus narrowly to broadly-shallowly depressed, 62–200 mm diam.; surface glabrous, smooth, wrinkled when dry, light yellow (1A4), yellowish white (4A2), yellowish grey (2B2, 2C2, 3C2), greyish yellow (4B4) when fresh, dull yellow (3B4), greyish-orange (5B5), brownish orange (5C6), orange or deep orange (6A7-8) when dry; margin often brighter, incurved when young, involute at maturity, incurved when dry; context up to 5 mm near the pileus center, yellowish white (2A2, 4A2) to yellowish gray (2B2, 4B2). Lamellae deeply decurrent, close, narrow, anastomosing near the stipe, pale yellow (3A3), orange gray (5B2) to grayish orange (5B3) when fresh, light brown (6D8), greyish orange (5B6) to brownish orange (6C8, 5C6) when dry; lamellar edges entire and usually darker in dried specimens; lamellulae present, 1–4 tiers. Partial veil present in young basidiomata, fugacious ( Fig. 3 B-C), but remaining for a time as appendiculate fragments on the pileus margin ( Fig. 3A ), single, yellowish white (4A2), annulus not seen. Stipe central to subeccentric, fleshy fibrous, solid, cylindrical to slightly attenuated upward, yellowish grey (4B2), greyish yellow (4B4), to brownish grey (5D2) when fresh, greyish orange (5B4-5) to brownish orange (5C5-6) when dry, 68–84 mm long, 9–23 mm thick, glabrous or with small fragile white squamules ( Fig. 3C ), fading in dry specimens.

Basidiospores [60/3/3] (8.4–)8.9–12.8(–13.8) × (3.2–)3.4–4.4(–4.6) µm (avg. = 10.7 × 3.9 µm), Q = 2.3–3.5, Qm = 2.8, IKI-, cylindrical to bacilliform, sometimes slightly wider at the anterior portion in side view, smooth, thin-walled, often bearing one or two guttules ( Fig. 3G ). Basidia (28–)30–46(–49) × (5.5–)6.0–8.0(–9.0) µm, cylindrical-clavate, hyaline, thin-walled or rarely thick-walled at base in some specimens, 4-sterigmate, with a basal clamp. Pleurocystidia (23–)28–38(–43) × 6.0–7.0(–7.5) µm, narrowly lageniform to narrowly obpyriform, seldom contracted in the median portion or close to the apex, apex obtuse, sometimes subcapitate, often apically mucronate to rostrate, thin- to thick-walled in the basal portion or toward to the apex, often bearing numerous small guttules or one wider in the apex, scattered or sometimes absent ( Fig. 3F ). Cheilocystidia 19–53(–62) × (3.5–)4.0–8.0(–10.0) µm, narrowly clavate, narrowly obpyriform, narrowly obutriform, obutriform or cylindrical, tapering towards the base, apex often flexuose, obtuse to almost acute, sometimes subcapitate, rarely mucronate to rostrate, thin- to more frequently thick-walled, rarely with small lateral tips, abundant ( Fig. 3E ). Hyphal system dimitic with clamp connections. Lamellar trama irregular, generative hyphae hyaline, frequently branched, sometimes very inflated, thin- to slightly thick-walled (up to 1 mm thick), (2.5–)3.0–9.0(–15) µm diam.; skeletal hyphae aseptate, rarely branched, hyaline, thick-walled (up to 2.5 mm thick), often solid, (2.5–)3.0–7.0(–8.0) µm. Subhymenium well developed, 16.0–30 µm wide, with pseudoparenchymatous, isodiametric, hyaline cells, (2.5–)3.0–12.5(–20) µm diam. Lamellar edges sterile, with cheilocystidia and slender hyphae 2–4 µm wide projecting up to 130 µm. Pileipellis a cutis, 11–60 µm wide, composed of generative hyphae repent to radially arranged, yellowish to brownish, thin- to slightly thick-walled (up to 0.5 µm thick), 2.0–6.0(–6.5) µm diam.; skeletal hyphae rare, similar to tramal skeletal hyphae. Pileus hyphal system composed of irregularly arranged thin- to slightly thick-walled (up to 1.0 µm thick), colorless and hyaline, generative hyphae (3.0–)3.5–13.5(–14.0) µm diam.; skeletal hyphae aseptate, rarely and rarely branched, hyaline, thick-walled (up to 2.5 mm thick), (3.0–)3.5–7.0 µm diam. Stipitipellis similar to pileipellis, composed of generative hyphae (5.0–)6.9–11.0 µm diam. Stipe hyphal system composed of irregularly arranged thin- to slightly thick-walled (up to 1.0 µm thick), colorless and hyaline, generative hyphae, (3.3–)3.6–7.5(–7.7) µm diam.; skeletal hyphae aseptate, rarely and rarely branched, hyaline, thick-walled (up to 2.5 mm thick), (2.8–)3–5.2(–5.7) µm diam.

Ecology and distribution:—On dead trunks of gymnosperms (FH 00543855, “in pino”) and angiosperms [i.e. Psidium ( Rick 1906) ]. Associated with the Araucaria Forest province and high-elevation sites in lower latitudes. Currently known from Southern and Southeastern Brazil, in the states of Rio Grande do Sul ( Rick 1906), Minas Gerais, Paraná, Santa Catarina, and São Paulo ( Araucaria Forest , Parana Forest and Pampean provinces, this work) ( Fig. 1 ).

Figures

FIGURE 1. Distribution map of Pleurotus magnificus (blue points) and P. rickii (red points) in South America. Colored areas are delimitations of biogeographic provinces according to Morrone (2014).

FIGURE 3. Morphological features of Pleurotus magnificus. A. Habit (FURB 44086, neotype); B. Detail of the partial veil remnants (SP 512761); C. Detail of the stipe and annulus (SP 512761); D. Hymenium and part of subhymenium (FURB 44086); E. Cheilocystidia (FURB 44086); F. Pleurocystidia (FURB 44086); G. Basidiospores (FURB 44086). Scale bars: A, B, C: 2 cm; D, E, F = 20 µm; G = 10 µm. Photos by F. Bittencourt (A) and M.P. Drewinski (B, C), illustrations by F. Bittencourt.

FIGURE 4. Known extant material of Pleurotus magnificus from 20th century. A. Rick 55 (FH 00543855); B. Plate from Theissen (1912); C. Rick 51 (Lloyd 740091). Photos provided by the Farlow Herbarium of Harvard University (A) and the U.S. National Fungus Collections (BPI) (C).