Marasmius tanaensis 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 : 141-142

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.

Figures

PLATE 8,Basidiocarps representingsect.Sicciser.Haematocephalia) Marasmius haematocephalus(JES 202) b)Marasmius ferruginoides (JES 209) c) Marasmius hinnuleus (JES 217). Scale bar = 10 mm. Photography by D.S. Newman.

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.