Marasmius tanaensis J. E. Shay & Desjardin 2017, sp. nov.
Creators: name: Shay, Jackie E.
name: Desjardin, Dennis E.
name: Perry, Brian A.
name: Grace, Chris L.
name: Newman, Danny S.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Agaricales
Marasmiaceae
Marasmius
Marasmius tanaensis

description: 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.   
 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.
description: Published as part of 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, pp. 101-149 in Phytotaxa 292 (2) on pages 141-142, DOI: 10.11646/phytotaxa.292.2.1, http://zenodo.org/record/13697833