Mycena alphitophora ( Berkeley 1877: 48 ) Saccardo (1887: 290)

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 : 26-28

10. Mycena alphitophora ( Berkeley 1877: 48) Saccardo (1887: 290) ( Figs. 19 , 20 )

Heterotypic synonyms:— Mycena osmundicola J.E. Lange (1914: 35) . Refer to Desjardin (1995) for additional synonyms.

Description:— Pileus 2–8 mm diam, ovoid to obtusely conical, convex or hemispherical, striate; surface covered with clusters of detersile, sugar-like granules, pure white overall. Context paper thin, translucent, white. Lamellae ascending, narrowly adnexed, subdistant with 1 series of lamellulae, narrow, white with concolorous edge. Stipe 10–15 × 0.5–1 mm, central, terete, cylindrical with a slightly enlarged base, lacking a basal disc, translucent; surface dull, dry, hispid above, strigose at base, pure white. Odour and taste not recorded. Bioluminescence undetected.

Basidiospores 6.4–8.0 × 4.0–4.8 μm [x m = 7.32 ± 0.54 × 4.56 ± 0.38 μm, Q = 1.33–1.80, Q m = 1.61 ± 0.07, n = 20, s = 1], ellipsoid, smooth, hyaline, amyloid, thin-walled. Basidia 11.2–14.4 × 7.2–11.2 μm, clavate, hyaline, inamyloid, thin-walled, 4-spored, sterigmata up to 3.2 μm long. Basidioles clavate. Cheilocystidia numerous, 13.6–23 × 8.8– 10.4 μm, clavate, densely spinulose over upper half, hyaline, inamyloid, thin-walled; spinulae 0.8–1.6 × 0.5–0.8 μm, cylindrical. Pleurocystidia absent. Pileipellis a cutis with acanthocysts; hyphae 4.0–8.8 μm diam, repent, cylindrical, smooth, hyaline, dextrinoid, thin-walled, non-gelatinous. Acanthocysts common, 17.6–30 × 13.6–29 μm, globose, densely spinulose, thin-walled, hyaline, inamyloid; spinulae 0.8–1.6 × 0.8–1.6 μm. Marginal cystidia uncommon, 23–56 × 13.6–16.8 μm, fusiform to clavate, densely spinulose, hyaline, inamyloid, thin-walled; spinulae 0.8–2.4 × 0.8–1.6 μm. Hypodermium composed of inflated hyphae up to 35 μm diam, globose to ovoid, hyaline, dextrinoid, thin-walled. Hymenophoral trama subregular; hyphae 1.6–7.2 μm diam, hyaline, dextrinoid, non-gelatinous, thin-walled. Stipitipellis a cutis; cortical hyphae 1.6–7.2 μm diam, parallel, cylindrical, smooth or rarely with knob-like diverticula, hyaline, dextrinoid, thin-walled; medullary hyphae 9.6–17.6 μm diam, smooth, hyaline, dextrinoid, thin-walled, occasional laticiferous hyphae with knob-like projections 1.6–4.8 μm diam. Caulocystidia abundant; 11–130 × 5.6–12.8 μm, cylindrical to fusiform, densely spinulose, hyaline, inamyloid, thin-walled; spinulae 0.8–2.4 × 0.8–1.6 μm. Clamp connections present in all tissues.

Habitat and known distribution:—Gregarious, lignicolous on undetermined dicot branches in primary forest. Widespread globally; Africa ( Kenya, São Tomé, Tanzania).

Material examined:—AFRICA. São Tomé, Macambrara radio antenna area, elevation 1100 m, N00˚16.554’, E06˚36.326’, 11 April 2008, D.E. Desjardin and B.A. Perry, BAP 591 ( SFSU) ; same location, 25 April 2006, D.E. Desjardin (material lost in transit) .

Notes:— Mycena alphitophora is a commonly encountered, widespread member of sect. Sacchariferae . The São Tomé specimen matches nicely material reported by Maas Geesteranus (1983), Desjardin (1995), and Pegler (1977; as M. osmundicola , from East Africa). It is characterized by small, white basidiomata with the pileus covered with sugar-like granules, narrowly adnexed lamellae, a hispid stipe, basidiospores in the range 6.4–10 × 4.0–5.5 μm, 4- spored basidia, clavate, spinulose cheilocystidia, no pleurocystidia, a pileipellis with numerous globose, spinulose acanthocysts, and cylindrical caulocystidia covered with spinulae.

Pairwise comparisons of aligned, overlapping ITS sequences of the São Tomé specimen (BAP 591) with the top ten BLAST results show 90–93.6% similarity to ten sequences of undetermined, uncultured fungus clones. Few sequences of members of sect. Sacchariferae are available for comparison, and no sequences of M. alphitophora from Bermuda (type location) are available in GenBank. A sequence determined as M. alphitophora (MH136831) from China is nearly identical to a sequence determined as M. corynephora (JF908369) from Italy, and together are sister to several members of sect. Sacchariferae from ST&P, including our São Tomé M. alphitophora , which is on a long branch ( Fig. 2).

Figures

FIGURE 19. Basidiomata of Mycena alphitophora (BAP 591). Scale bar = 10 mm.

FIGURE 20. Mycena alphitophora (BAP 591).a. Basidiospores.b. Basidia.c. Cheilocystidia.d.Acanthocysts.e. Pileus marginal cystidia. f. Caulocystidia. Scale bar = 10 μm.