Marasmius siccus (Schwein.) Fr.

S, Jadson José, Oliveira, ouza de, Capelari, Marina, Margaritescu, Simona & Moncalvo, Jean-Marc, 2022, Disentangling cryptic species in the Marasmius haematocephalus (Mont.) Fr. and M. siccus (Schwein.) Fr. species complexes (Agaricales, Basidiomycota), Cryptogamie, Mycologie 20 (5), pp. 91-137 : 124-125

Marasmius siccus (Schwein.) Fr.

Epicrisis Systematis Mycologici, seu Synopsis Hymenomycetum: 382 ( Fries 1838). — Type: United States. North Carolina (Salem) or Pennsylvania (Bethlehem): “Salem-Beth.”, Schweinitz, no date (holo-,PH[PH00062046]) (based on Desjardin [1989]).

Agaricus siccus Schwein., Schriften der Naturforschenden Gesellschaft zu Leipzig 1: 84 ( Schweinitz 1822).

Chamaeceras siccus (Schwein.) Kuntze, Revisio generum plantarum (Leipzig) 3 (3): 457 ( Kuntze 1898).

REFERENCE STRAINS. — United States. Tennessee, 19.VII.1991, D.E. Desjardin DED5255 (SFSU[SFSU-F-029078]; GenBank: FJ431272 ); J.N. Hill JNH010 (TENN[TENN-F-070783]; GenBank: MF686511 ) as Marasmius fulvoferrugineus ; V. Antonín (BRNM[BRNM 552709]; GenBank: HQ607384 ), published in Antonín et al. (2012).

REMARKS

Marasmius siccus s. str. regards DED5255, a topotype specimen collected and determined by Dr Dennis E. Desjardin, as the most authentic for the species in the phylogenetic trees (Figs 1; 2). The species is known by the umbrella-like basidiomata (the orange pinwheel) that are somewhat larger and more robust than M. haematocephalus , with a membranous, radially sulcate, yellow-orange-brown pileus (2.5-27 mm diam.) with darker center, a filiform to cylindrical, glabrous, brown stipe ([17-]23-62[-85] × 0.2-1.25 mm) with a floccose basal mycelium, and distant, whitish (15-22) lamellae (lamellulae often absent or 1-2) ( Gilliam 1976; Desjardin 1989). Desjardin (1989: 671-674) revised the holotype that singly had oblong, 15.2-20.4 × 3.4-4 µm (n = 13) basidiospores, refractive, well-developed, 32-56 × 5.5-8 µm pleurocystidia, and a pileipellis composed of orangish to brownish Siccustype broom cells. His review of the type specimen ( Desjardin 1989: 671-674) as well as the description based on fresh collections ( Desjardin 1989: 246-249) agreed with Gilliam (1976), especially in the dimensions of basidiospores (15.2- 20.8 × 3.2-4.6 µm vs [13.3-]16-21[-23] × 2.8-4.2[-5] µm, respectively) and of pleurocystidia (32-60 × 5-9 µm vs 23-67[- 81] × 3-14 µm, respectively). Besides the holotype, examined collections from the United States included in Desjardin (1989) were from Connecticut, Delaware, Idaho, Illinois, Indiana, Kansas, Maryland, Michigan, Minnesota, Nebraska, New Hampshire, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, West Virginia, Wisconsin, along with one collection from Japan. Gilliam (1976) also included to the list of states in United States collections from the District of Columbia, Massachusetts and Missouri, besides collections from Ontario ( Canada) and Japan. So, the North American collections are the preferred starting point to delimit M. siccus . The pantemperate species concept recognizes the taxon as widespread across the subarctic, boreal and temperate zone of the northern hemisphere with circumpolar distribution ( Noordeloos 1987; Antonín & Noordeloos 2010) based on collections from Canada, Finland, Norway, Republic of Korea, Russia, Sweden, and United States. This pantemperate M. siccus would cover specimens with larger spores (15-23 × 4-5 µm in Noordeloos [1987] and 15-23.5 × [2.5-]3-4.5[-5] µm in Antonín & Noordeloos [2010]) and larger pleurocystidia (25-70 × 5-10 µmNoordeloos [1987] and 25-80 × 5-21.5 µm in Antonín & Noordeloos [2010]) than those predominantly from North America ( Gilliam 1976; Desjardin 1989). Noordeloos (1987) and Antonín & Noordeloos (2010) also included collections from North America that should be M. siccus s. str. This species has been referred as a very variable species, or with a broad concept, or one of the most misapplied binomials of Marasmius ( Gilliam 1976; Desjardin 1989; Antonín & Noordeloos 2010), usually confused with M. bellipes Morgan , M. borealis Gilliam , M. glabellus Peck , M. ferrugineus , M. fulvoferrugineus Gilliam , M. pulcherripes and M. robinianus Gilliam.

Based on nrITS, the Nearctic M. siccus s. str. (DED5255) is 1.6-3.5 dissimilar to the Palearctic M. siccus lineages. Strains of M. siccus s. str. without preserved basidiomata collection, solely based on the GenBank accessions are: GU328526 ( United States, Michigan, 44°48’N, 85°48’W, date unshown, environmental sample “man22_litter_H12” in Edwards & Zak [2010]). Dedicated to the M. siccus complex, a review study of the involved collections in the phylogenetic analyses herein and/or fresh collections should be carried out considering M. siccus s. str. and the other close/cryptic species across the temperate zone based on siccus_cp1 (Figs 1; 2).