Mycena lasiopus Maas Geest. & de Meijer (1998: 37)

Cooper, Alexandra C., Desjardin, Dennis E. & Perry, Brian A., 2018, The genus Mycena (Basidiomycota, Agaricales, Mycenaceae) and allied genera from Republic of São Tomé and Príncipe, West Africa, Phytotaxa 383 (1), pp. 1-47 : 29-30

12. Mycena lasiopus Maas Geest. & de Meijer (1998: 37) ( Fig. 22 )

Description:— Pileus up to 3mm diam, broadly convex to paraboloid, striatulate; surface minutely pruinose, covered with dark brown to black granules, background pale grey. Lamellae ascending-adnate, subdistant (10–11) with 2 series of lamellulae, white. Stipe 5–7 × 0.5 mm, central, cylindrical, covered with scattered pubescence, white, arising from a white, striate basal disc and white tomentum. Odour and taste not recorded. Bioluminescence undetected.

Basidiospores 8.0–9.6 (–10.5) × 4.0–5.6 μm [x mr = 9.0–9.2 × 4.5–5.0 μm, x mm = 9.06 ± 0.1 × 4.77 ± 0.4, Q = 1.6–2.4, Q mr = 1.79–2.04, Q mm = 1.91 ± 0.2, n = 20, 21, s = 2], ellipsoid, smooth, hyaline, weakly amyloid, thin-walled. Basidia 8.0–16.8 × 6.4–8.8 μm, broadly clavate, hyaline, inamyloid, thin-walled, 4-spored, sterigmata up to

2.4 μm long. Basidioles clavate. Cheilocystidia numerous, 12.8–29.6 × 5.6–10.4 μm, clavate, densely spinulose over upper half, hyaline, inamyloid; spinulae 0.8–4 × 0.8–1.6 μm, cylindrical. Pleurocystidia absent. Pileipellis a cutis with acanthocysts and cherocytes; hyphae 0.8–4.0 μm diam, repent, cylindrical, with brownish contents, smooth, hyaline, dextrinoid, thin-walled, non-gelatinous. Acanthocysts common, 15.2–26.4 × 14.4–23.2 μm, globose, densely spinulose, thin-walled, with homogeneous brown contents, hyaline, inamyloid; spinulae 0.8–1.6 × 0.5–0.8 μm. Cherocytes uncommon, 23.2–28.8 × 13.6–21.6 μm, irregular in shape, densely spinulose, thick-walled (1.6–4.0 μm), with homogeneous brown contents, hyaline, inamyloid; spinulae 0.8–1.6 × 0.5–0.8 μm, cylindrical. Hypodermium composed of parallel hyphae up to 19.2 μm diam. Hymenophoral trama regular; hyphae 2.4–19.2 μm diam, hyaline, dextrinoid, non-gelatinous, thin-walled. Stipitipellis a cutis; cortical hyphae 2.4–5.6 μm diam, parallel, cylindrical, hyaline, dextrinoid, thin-walled; medullary hyphae 7.2–17.6 μm diam, smooth, hyaline, dextrinoid, thin-walled, occasional laticiferous hyphae with knob-like projections 2.4–3.2 μm long. Caulocystidia abundant; 23.2–600 × 5.6– 10.4 μm, cylindrical for most of length, gradually narrowing toward the broadly rounded apex, densely spinulose at base with less spinulae at apex, hyaline, inamyloid, thin-walled; spinulae 0.8–2.4 × 0.5–0.8 μm, cylindrical. Basal disc with cherocytes and acanthocysts as on pileus surface and cystidia like the caulocystidia. Clamp connections present in all tissues.

Habitat and known distribution:—Gregarious on woody debris in forest with cacao or on sticks in secondary, upland forest, Africa ( Príncipe, São Tomé); Brazil (Paraná).

Material examined:—AFRICA. Príncipe, along trail to Roça Pico Papagaio, N01˚37.182’, E07˚23.474’, 21 April 2008, on sticks in secondary, upland forest, D.E. Desjardin and B.A. Perry, BAP 635 (SFSU). São Tomé, along main road (EN2) on south side of island approx. 200 m east of 38 km marker, N00˚08.500’, E06˚39.560’, 13 April 2008, on woody debris in forest with cacao, D.E. Desjardin and B.A. Perry, BAP 603 (SFSU).

Notes:— Mycena lasiopus , described from Paraná State, Brazil, is distinguished by tiny basidiomata with grey pileus covered with dark brown granules, subdistant white lamellae, a white, pubescent stipe arising from a striate basal disc, basidiospores with mean 9 × 4.8 μm (Q = 1.9), densely spinulose, clavate cheilocystidia, a pileipellis with brown, densely spinulose, globose, thin-walled acanthocysts and irregular-shaped, thick-walled cherocytes, very long, cylindrical, densely spinulose caulocystidia, and growth on woody debris. The specimens from São Tomé and Príncipe are indistinguishable from the description of original material from Brazil ( Maas Geesteranus and de Meijer 1998). The species belongs in sect. Sacchariferae , stirps Amparoina sensu Desjardin (1995) .

Pairwise, aligned sequences of M. lasiopus (BAP 603, BAP 635) with the top ten BLAST results show 88.3– 89.2% similarity to M. corynephora (JF908366, JF908367, JF908368, JF908369), a north temperate member of sect. Sacchariferae , stirps Alphitophora . Unfortunately, few sequences of members of sect. Saccharifera are available for comparison. Mycena corynephora is very different. It forms a pure white pileus lacking cherocytes, a stipe that lacks a basal disc, and globose to subglobose basidiospores (Q = 1.0–1.1) ( Maas Geesteranus 1983). In the ITS phylogeny ( Fig. 2), M. lasiopus clusters with two additional members of sect. Sacchariferae from ST&P ( M. oboensis , M. alphitophora ) in a clade with other members of the section (92% BS, 1.0 PP support).

Figures

FIGURE 22. Mycena lasiopus (BAP 603). a. Basidiospores. b. Basidia and basidiole. c. Cheilocystidia. d. Acanthocysts. e. Cherocytes. f. Caulocystidia. Scale bar = 10 μm.