Marasmius madagascariensis J.E. Shay & Desjardin, 2017

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 : 124-125

16. Marasmius madagascariensis J.E. Shay & Desjardin , sp. nov. ( Fig. 11 , Plate 4 )

MycoBank no.: MB 818620

Holotype:— MADAGASCAR. Region Vatovavy-Fitovinany , District Ifanadiana , Commune Ranomafana , Ranomafana National Park, Circuit Vohiparara, elev. 1062 m, GPS: 21˚ 14.255’ S, 47˚ 23.409’ E, 21 January 2014, J. E. Shay 139 ( SFSU).

Etymology:— madagascar-iensis –occurring in Madagascar.

Description:— Pileus 2–6 mm diam, convex to campanulate, umbilicate, with a reddish brown papilla; margin sulcate;

surface dry, glabrous; orangish brown (6C–D7, 5B6–7). Context thin (<1 mm), concolorous with pileus. Lamellae adnate to a collarium, subdistant (9–11), broad (0.5–1 mm), light orange (5A4) to cream, non-marginate. Stipe 10–

23 × 0.1–1 mm, central, hollow, wiry, insititious; surface glabrous; black; rhizomorphs present. Odor and taste not distinctive.

Basidiospores 8.8–12.8 × 4–5.6 (–7.2) μm [x mr = 11.3–11.6 × 4.8–5.0 μm; x mm = 11.46 ± 0.17 × 4.90 ± 0.09 μm; Q = 1.8–3.2; Q mr = 2.36–2.38; Q mm = 2.37 ± 0.02, n = 21–22, s = 2], ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 18.4–26.4 × 9.6–11.2 μm, clavate, 4-spored, hyaline, inamyloid. Basidioles 13.6–24.8 × 4.8–8.5 μm, clavate to cylindrical, hyaline, inamyloid, thin-walled. Cheilocystidia of Siccus - type broom cells; main body 8–19.2 × 6.4–11.2 μm, clavate to cylindrical, seldom lobed, hyaline, inamyloid, thin-walled; apical setulae 0.8–6.4 × 0.5–2 μm, cylindrical to conical, often branched, hyaline, inamyloid, thin-walled. Pleurocystidia absent. Pileipellis mottled, a hymeniform layer of Siccus - type broom cells; main body 8–16 × 6.4–16 μm, clavate or irregular, 2–3-lobed, hyaline, inamyloid, thin-walled; apical setulae 1.6–5.6 × 0.5–2 μm, cylindrical to conical, sometimes branched, yellowish brown to hyaline, inamyloid, thin-walled. Pileus trama interwoven; hyphae 2.4–4.8 μm diam, cylindrical, smooth, hyaline, inamyloid, thin-walled. Lamellar trama regular; hyphae 1.6–12 μm diam, cylindrical to inflated, smooth, hyaline, inamyloid, thin-walled. Stipe tissue monomitic; cortical hyphae 2–4 μm diam, parallel, cylindrical, smooth, brown, dextrinoid, thick-walled; medullary hyphae 2.4–8 μm diam, parallel, cylindrical, smooth, hyaline, weakly dextrinoid, thin-walled. Caulocystidia absent. Clamp connections present.

Habit, habitat and known distribution:—Solitary or gregarious on stems of Cyathea (tree fern, Cyatheaceae ) and on debris of an unknown grass ( Poaceae ). Madagascar.

Material examined:— MADAGASCAR. Region Vatovavy-Fitovinany , District Ifanadiana , Commune Ranomafana , Ranomafana National Park, Circuit Vohiparara, elev. 1062 m, GPS: 21˚ 14.255’ S, 47˚ 23.409’ E, 21 January 2014, J. E. Shay 139 ( SFSU) ; Region Analamanga , District Ankazobe , Commune Ambatoharanama , Ambohitantely Forest Reserve Sentier Botanique, 1574 m, GPS: 18˚ 11.504’ S, 47˚ 17.074’ E, 8 Feb. 2014, J. E. Shay 225 ( SFSU) .

Notes:— Marasmius madagascariensis is characterized by small (2–6 mm diam), orangish brown pileus with a reddish brown central papilla, distant (9–11), collariate, non-marginate lamellae, a wiry stipe <23 mm long, abundant rhizomorphs, basidiospores with mean 11.5 × 4.9 μm, Siccus - type broom cells, and growth on grass leaves and tree fern stems. Morphologically it is similar to M. guyanensis Mont. , a species described originally from French Guyana (South America), and subsequently reported from the Caribbean region, Indonesia, Singapore, Malaysia, Thailand and Africa. Morphologically, the Madagascar specimens are most similar to Thailand M. guyanensis where basidiomes are formed on dicot leaves and have basidiospores with mean width 3.8 μm. In comparison, the Madagascar specimens differ in growing on grass leaves and tree fern stems and have basidiospores with mean width 4.9 μm. ITS sequences of Madagascar material of M. madagascariensis (KX149015, KX149006) are on a long branch embedded in a clade with two Malaysian specimens determined as M. guyanensis (FJ431246, FJ431247; Tan et al. 2009), two specimens of M. crinisequi , and two Thai specimens of M. guyanensis (EU935552, EU935553; Wannathes et al. 2009a). In addition, the Madagascar specimens are morphologically similar to M. aff. guyanensis reported from the island of Princípe (DED 8285, Grace et al., unpubl.), but the latter has longer and narrower basidiospores (12.5–15 × 3.5–4.5 μm), and an insertion of 38 base pairs (between 593–630) in the ITS region. Because of its distribution in Madagascar, subtle differences in basidiospore size and substrate, and ITS sequence differences, we recognize the Madagascar material as a distinct species.

Figures

PLATE 4. Basidiocarps representing sect. Marasmius subsect. Sicciformes. a) Marasmius madagascariensis (JES 225); sect. Globulares b) Marasmius bekolacongoli (Lockwood 2131638), photo generously donated by Taylor Lockwood. Scale bar = 10 mm (a); 20 mm (b). Photography by D.S. Newman.

FIGURE 11. Marasmius madagascariensis (JES 139, JES 225) a) basidiospores; b) basidia; c) basidioles; d) cheilocystidia; e) pileipellis cells. Scale bar = 10 μm. Illustrated by J.E. Shay.