Marasmius bambusiniformis Singer, Fl. Neotrop. Monogr.

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 : 138-139

28. Marasmius bambusiniformis Singer, Fl. Neotrop. Monogr. 17: 167. 1976. ( Fig. 19 , Plate 7 )

Type:— ECUADOR. Napo, Lago Agrio, 16 May 1973, Singer B 7480 ( F!)

Description:— Pileus 4–5 mm diam, convex to campanulate; margin smooth to sulcate; surface dull, dry, glabrous; reddish orange becoming more orange towards the margin (6 C – E 8). Context thin, white. Lamellae adnate, distant (12–17), no lamellulae, not intervenose, narrow; white with reddish brown edges. Stipe 25–30 × 0.5–1 mm, central, cylindrical, hollow, wiry; surface glabrous, apex white (3 A 3), grading to brownish orange (6 C – E 5–8) at the base. Odor and taste not distinctive.

Basidiospores (14.4–) 16–18.4 × 3.2–4 μm [x m = 16.35 ± 1.44 × 3.46 ± 0.36 μm; Q = 4–5.75; Q m = 4.76 ± 0.57, n = 25, s = 1], narrowly ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia not observed. Basidioles 19.2–24 × 5.6– 7.2 μm, clavate to fusoid, hyaline, inamyloid, thin-walled. Cheilocystidia numerous, of Siccus - type broom cells; main body 9.6–14.4 × 5.6–10.4 μm, clavate to broadly clavate, seldom 2–3-lobed, hyaline, inamyloid, apically thick-walled; apical setulae 1.6–7.2 × 0.8 μm, dense, cylindrical to conical, seldom branched, hyaline, inamyloid, thick-walled. Pleurocystidia absent. Pileipellis mottled, a hymeniform layer of Siccus - type broom cells; main body 10.4–17.6 × 6.4–8 μm, clavate to broadly clavate, seldom 2–3-lobed, hyaline, inamyloid, apically thick-walled; apical setulae 1.6– 4.8 × 0.8 μm, dense, cylindrical to conical, pale yellowish brown, inamyloid, thick-walled. Pileus trama interwoven; hyphae 1.6–16.8 μm diam, cylindrical, smooth, hyaline, inamyloid, thin-walled. Lamellar trama regular; hyphae 1.6–8 μm diam, cylindrical to inflated, smooth, hyaline, dextrinoid, thick-walled. Stipe tissue monomitic; cortical hyphae 1.6–4 μm diam, parallel, cylindrical, smooth, dark brown, dextrinoid, thick-walled; medullary hyphae 2.4–8 μm diam, parallel, cylindrical to inflated, hyaline, dextrinoid, thin-walled. Caulocystidia absent. Clamp connections present.

Habit, habitat, and known distribution:—Solitary on stems of Uapaca ( Phyllanthaceae ). Malaysia, Madagascar, Papua New Guinea, South America ( Brazil. Ecuador), Thailand, United States (Florida).

Material examined:— MADAGASCAR. Region Alaotra-Mangoro, District Moramanga, Commune Andasibe, Vohimana Forest, Piste 5, elev. 844 m, GPS: 18˚ 55.422’ S, 48˚ 30.201’ E, 27 January 2014, J. E. Shay 199 ( TAN).

Notes:— Marasmius bambusiniformis was described originally from Ecuador ( Singer 1976), and subsequently reported from Papua New Guinea ( Desjardin & Horak 1997), Malaysia ( Tan et al. 2009) and Thailand ( Wannathes et al. 2009a). Distinctive features include a small (3–10 mm diam), obtusely conical, striate, reddish orange pileus, distant (12–17) lamellae with reddish orange edges, a glabrous, non-insititious stipe lacking caulocystidia, no pleurocystidia, Siccus - type broom cells, and growth on dicotyledonous leaves and twigs. The material from Madagascar ( JES 199) matches nicely that reported from Southeast Asia and Papua New Guinea, and ITS sequences support this determination.

Marasmius conicoparvus Antonín, C. Sharp & Stubbe is quite similar, differing primarily in forming non-marginate lamellae and slightly shorter basidiospores (13–16 μm); this may represent the same taxon as what we report from Madagascar, but until more material becomes available for comparison and sequencing, we prefer to recognize the Madagascan taxon as M. bambusiniformis . Marasmius berteroi (Lév.) Murr. described from Puerto Rico, and reported from Indonesia ( Desjardin et al. 2000), is similar but has non-marginate lamellae and shorter basidiospores (12–16 μm). An ITS sequence of JES 199 ( KX 148990) is sister to a Thai specimen of M. bambusiniformis ( EU 935521) and together are sister to M. berteroi ( FJ 917632) ( Fig. 1a )

Figures

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.

PLATE 7. Basidiocarps representing sect. Sicci ser. Leonini a) Marasmius megistus (JES 163) b) Marasmius megistus (Lockwood 2132155), photo generously donated by Taylor Lockwood, c) Marasmius bambusiniformis (JES 199). Scale bar = 10 mm (a, c); 5 mm (b). Photography by D.S. Newman.

FIGURE 19. Marasmius bambusiniformis (JES 199) a) basidiospores; b) basidioles; c) cheilocystidia; d) pileipellis cells. Scale bar = 10 μm. Illustrated by J.E. Shay.