Marasmius rotalis Berk. & Broome, J. Linn. Soc., Bot.

Shay, Jackie E., Desjardin, Dennis E., Perry, Brian A., Grace, Chris L. & Newman, Danny S., 2017, Biodiversity and phylogeny of Marasmius (Agaricales, Basidiomycota) from Madagascar, Phytotaxa 292 (2), pp. 101-149 : 111-112

1. Marasmius rotalis Berk. & Broome, J. Linn. Soc., Bot. 14: 40. 1873 (1875). ( Fig. 2 , Plate 1 )

Type:— SRI LANKA. Peradeniya, Thwaites 810 ( K!)

Description:— Pileus 1–5 mm diam, campanulate to umbilicate, shallowly depressed; margin plicate to sulcate, crenate; surface dry, glabrous; white to buff or pale gray (5 B 2–3). Context thin, concolorous. Lamellae adnate to a collarium, distant (8–11), no lamellulae, non-intervenose, broad (0.5–0.8 mm), white, non-marginate. Stipe 8–54 × 0.2 mm, central, cylindrical, hollow, wiry, insititious; surface glabrous; dark brown to black overall. Odor and taste not distinctive.

Basidiospores (6.4–) 7.2–10.4 (–11.2) × 3.2–4.8 (–5) μm [x mr = 8.4–8.9 × 3.7–4.2 μm; x mm = 8.7 ± 0.3 × 4.0 ± 0.3 μm; Q = 1.5–3.3; Q mr = 2.09–2.28; Q mm = 2.19 ± 0.1, n = 24–25, s = 3], ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia not observed. Basidioles 13.6–23.2 × 4–8 μm, clavate to fusoid, some utriform, hyaline, inamyloid,

thin-walled. Cheilocystidia numerous, of Rotalis - type broom cells; main body 6.8–20 × 8–22.4 μm, clavate to broadly clavate, globose, subglobose or obpyriform, hyaline, inamyloid, thin-walled; divergent setulae 0.5–2.4 × 0.5–2.4

μm, cylindrical to conical, obtuse, hyaline, inamyloid, thin-walled. Pleurocystidia absent. Pileipellis not mottled, a hymeniform layer of Rotalis - type broom cells; main body 8–34 × 8–28 μm, clavate to broadly clavate, subglobose or globose, pale yellowish brown to hyaline, inamyloid, thin-walled; divergent setulae 0.5–3 × 0.2–1.6 μm, numerous,

cylindrical to conical, pale yellowish brown to hyaline, inamyloid, thin-walled. Pileus trama interwoven; hyphae 1.6–

4.8 μm diam, cylindrical, smooth, hyaline, inamyloid, thin-walled. Lamellar trama regular; hyphae 1.6–9.6 μm diam,

cylindrical to slightly inflated, smooth, hyaline, inamyloid, thin-walled. Stipe tissue monomitic; cortical hyphae 3–4 μm diam, parallel, cylindrical, smooth, yellowish brown to brown, dextrinoid, thick-walled; medullary hyphae 1.6–6 μm diam, parallel, cylindrical, smooth, hyaline, inamyloid, thin-walled. Caulocystidia absent. Clamp connections present.

Habit, habitat, and known distribution:—Solitary or gregarious on leaves of Cephalostachium vigueri (bamboo), Cynodon dactylon ( Poaceae ), and various unknown dicotyledonous leaves and stems. Africa ( Benin, Cameroon, DR Congo, Kenya, Malawi, Nigeria, Tanzania, Uganda), Indonesia (Java), Madagascar, Papua New Guinea, South America ( Colombia), Sri Lanka.

Material examined:— MADAGASCAR. Commune Ranomafana , District Ifanadiana , Region Vatovavy-Fitovinany , Ranomafana National Park, Circuit Vohiparara, elev. 1062 m, GPS: 21˚ 14.255’ S, 47˚ 23.409’ E, 21 January 2014, J. E. Shay 141 ( SFSU) & J. E. Shay 145 ( SFSU) ; Piste B, elev. 1004 m, GPS: 21˚ 15.413’ S, 47˚ 25.253’ E, 22 January 2014, J. E. Shay 150 B ( SFSU) .

Notes:— Marasmius rotalis forms small (1–5 mm diam), white to pale grayish pilei, distant (8–11), collariate lamellae, dark brown, wiry insititious stipe, basidiospores in the range 7.2–10.4 × 3.2–5 μm, Rotalis - type broom cells, and growth on dicotyledonous leaves, bamboo or various grasses. A quick comparison with M. apatelius indicates that they differ primarily in pileus color, paler and whitish in M. rotalis and more brownish in M. apatelius . ITS sequences of the Madagascar specimens of M. rotalis ( KX 148999, KX149000, KX 149001) align with GenBank sequences of M. rotalis and M. rotula , in a clade with other members of sect. Marasmius subsect. Marasmius . ( Fig. 1c ).

Figures

PLATE 1. Basidiocarps representing sect. Marasmius subsect. Marasmius a) Marasmius rotalis (JES 154) b) Marasmius apatelius (JES 203) c) Marasmius somalomoensis (JES 129). Scale bar = 5 mm (a); = 10 mm (b, c). Photography by D.S. Newman.

FIGURE 1a. Maximum likelihood phylogeny based on ITS sequence data. Marasmius from Madagascar are indicated in bold type.Values separated by / refer to nonparametric ML bootstrap proportions and Bayesian posterior probabilities, respectively. Values greater than 70/0.70 are shown (- designates a value below 70% or below 0.70). Nodes receiving support values greater than 90/0.95 are represented by bold branches. G—sect. Globulares; N—sect. Neosessiles; SA—sect. Sicci ser. Atrorubentes; SL—sect. Sicci ser. Leonini; SH—sect. Sicci ser. Haematocephali.

FIGURE 2. Marasmius rotalis (JES 141, JES 145, JES 150B) a) basidiospores; b) basidioles; c) cheilocystidia; d) pileipellis cells. Scale bar = 10 μm. Illustrated by J.E. Shay.