Biodiversity and phylogeny of Marasmius (Agaricales, Basidiomycota) from Madagascar Author Shay, Jackie E. Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132, USA Author Desjardin, Dennis E. Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132, USA Author Perry, Brian A. Author Grace, Chris L. Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132, USA Author Newman, Danny S. Department of Biology, San Francisco State University, 1600 Holloway Ave., San Francisco, CA 94132, USA text Phytotaxa 2017 2017-01-25 292 2 101 149 http://dx.doi.org/10.11646/phytotaxa.292.2.1 journal article 10.11646/phytotaxa.292.2.1 1179-3163 13697833 30. Marasmius tanaensis J.E. Shay & Desjardin sp. nov. ( Fig. 21 , Plate 8 ) MycoBank no.: MB 818618 Holoype:— MADAGASCAR . Region Analamanga, City of Antananarivo , Parc Botanique de Zoologique (P.B.Z.T.), near the garden of Crops Wild and Relatives (CWR), elev. 1270 m , GPS: 18˚ 55.530’ S, 47˚ 31.350’ E, 8 Feb. 2014 , J.E. Shay 220 (SFSU). Etymology:— tana-ensis –occurring in “tana”, the local name for Antananarivo where the holotype specimen was collected. Description:— Pileus 1–3 mm diam, convex to hemispherical; margin smooth to striate; surface dull, dry, glabrous; light orange (6A4) to orange (6B6). Context thin, pale orangish pink to light orange (6A3–4). Lamellae adnexed, subdistant (14–15), no lamellulae, narrow (< 0.3 mm ); white, non-marginate. Stipe 1–22 × 0.1–0.5 mm , central, cylindrical, wiry, hollow; surface glabrous; white at apex, becoming brownish orange (6B–C4-6) to brown (6E7) at the base. Odor and taste not distinct. FIGURE 21 . Marasmius tanaensis ( JES 220 ) a) basidiospores; b) basidia; c) basidioles; d) cheilocystidia; e) pleurocystidia; f) pileipellis cells. Scale bar = 10 μm. Illustrated by J.E. Shay. Basidiospores 11.2–16 × (3.2–) 4–4.8 (–5.6) μm [x m = 13.37 ± 1.41 × 4.26 ± 0.49 μm; Q = 2.43–5.0; Q m = 3.19 ± 0.26, n = 31, s =1], broadly ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 22.4 × 5.6–6.4 μm clavate, 4-spored, hyaline, inamyloid, thin-walled; sterigmata 2.4–3.2 × 0.8 μm. Basidioles 8.8–28.8 × 4.8–7.2 μm, clavate to fusoid, hyaline, inamyloid, thin-walled. Cheilocystidia abundant, of Siccus - type broom cells; main body 16–29.6 × 4–8 μm, clavate to broadly clavate, seldom 2–3 lobed, hyaline, inamyloid, thin-walled; apical setulae 0.8–4 × 0.8, cylindrical to conical, seldom branched, hyaline to light brown, inamyloid, thick-walled. Pleurocystidia 22–48 × 6–9.5 μm, utriform to fusiform, mucronate, hyaline, inamyloid, thin-walled. Pileipellis mottled, a hymeniform layer of Siccus - type broom cells; main body 12–16.8 × 4.8–9.6 μm, clavate to broadly clavate, seldom 2–3 lobed, hyaline, inamyloid, thin-walled; apical setulae 0.8–5.6 × 0.8–1.6 μm, clustered, cylindrical to conical, seldom branching, light brown, inamyloid, thick-walled. Pileus trama interwoven; hyphae 2.4–12 μm diam, cylindrical to inflated, smooth, hyaline, dextrinoid, thin-walled. Lamellar trama regular; hyphae 3.2–8.8 μm diam, cylindrical to inflated, smooth, hyaline, dextrinoid, thick-walled. Stipe tissue monomitic; cortical hyphae 2.4–6.4 μm diam, parallel, cylindrical, smooth, pale light brown, dextrinoid, thick-walled; medullary hyphae 3.2–8.8 μm diam, parallel, cylindrical to inflated, smooth, hyaline, dextrinoid, thin-walled. Caulocystidia absent. Clamp connections present. Habit, habitat and known distribution:—Clustered on bamboo debris. Madagascar . Material examined:— MADAGASCAR .Region Analamanga,City of Antananarivo , Parc Botanique de Zoologique (P.B.Z.T.), near the garden of Crops Wild and Relatives (CWR), elev. 1270 m , GPS: 18˚ 55.530’ S, 47˚ 31.350’ E, 8 February 2014 , J.E. Shay 220 (SFSU). Notes:— Marasmius tanaensis forms tiny ( 1–3 mm diam), smooth to striate, orange pilei, subdistant (14–15), non-marginate lamellae, a short (up to 22 mm ), glabrous, white (upper half) to brown (base) stipe that grows on bamboo debris, basidiospores with mean 13.4 × 4.3 μm, narrow (6–9.5 μm), mucronate pleurocystidia, Siccus -type cheilocystidia and pileipellis cells, and no caulocystidia. The small orange pilei and growth on bamboo debris is similar to M. bambusinus (Fr.) Fr. , described from Brazil , but the latter forms fewer lamellae (6–13), longer basidiospores (13.8–22 μm), and broader pleurocystidia (8–12.5 μm diam) ( Singer 1976 ). We were unable to obtain a quality ITS sequence from the holotype specimen.