Mycena lamprospora (Corner) E. Horak (1978: 22)

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 : 32-34

14. Mycena lamprospora (Corner) E. Horak (1978: 22) ( Figs. 24, 25 )

Basionym:— Mycena rorida var. lamprospora Corner (1950: 427) .

= Roridomyces lamprosporus (Corner) Rexer (1994: 140) .

Description:— Pileus 4–6 mm diam, hemispherical with a flattened disc, margin undulate, shallowly striate; surface moist, disc appressed fibrillose with short brown fibrils and pale brown tones, glabrous and off-white at margin.

Lamellae decurrent, subdistant (14–15) with 1–2 series of lamellulae, white with concolorous edge. Stipe 15–23 ×

0.5–1 mm, central, terete, cylindrical; surface with a thick, hyaline, glutinous layer, apex with minute white granules,

pearlescent, greyish white, base with yellowish brown tones. Odour indistinct; taste not recorded. Bioluminescence undetected.

Basidiospores 6.4–8.8 × 3.2–4.8 μm [x m = 7.48 ± 0.66 × 3.84 ± 0.56 μm, Q = 1.60–2.50, Q m = 1.98 ± 0.38, n = 20, s = 1], ellipsoid, smooth, hyaline, amyloid, thin-walled. Basidia 8.8–20.8 × 4–7.2 μm, clavate, hyaline, inamyloid, thinwalled, 4-spored, sterigmata up to 3.2 μm long. Basidioles clavate to lageniform. Lamellar edge sterile. Cheilocystidia of 2 types: 1) 27.2–40.8 × 8.8–10.4 μm, clavate to subclavate, hyaline, inamyloid, thin-walled; 2) 18.4–25.6 × 5.6–6.4 μm, clavate to subclavate with a few irregular apical projections, hyaline, inamyloid, thin-walled. Pleurocystidia absent. Pileipellis an interrupted cutis to trichoderm with irregular or sphaeropedunculate terminal cells; hyphae 2.5–5 μm diam, cylindrical or irregular, smooth or with scattered projections, hyaline or with brown contents, inamyloid, thin-walled. Terminal cells of 2 types: 1) 20–60 × 4–6 μm, irregularly cylindrical with scattered projections, with brown contents, inamyloid, thin-walled; 2) 24–44 × 8.8–16.8 μm, sphaeropedunculate, hyaline, inamyloid, thin-walled. Hypodermium composed of inflated cells up to 25 μm diam, globose to ovoid, smooth, hyaline, dextrinoid, thin-walled. Hymenophoral trama subregular; hyphae 2.4–5.6 μm diam, hyaline, dextrinoid, non-gelatinous, thin-walled. Stipitipellis a cutis with erect caulocystidia; cortical hyphae 1.6–4.8 μm diam, parallel, cylindrical, hyaline, dextrinoid, thin-walled; medullary hyphae 5.6–15.2 μm diam, smooth, dextrinoid, thin-walled; terminal cells diverticulate. Caulocystidia abundant; 31–42 × 6.4–9.6 μm, clavate or subcapitate, with occasional scattered projections, hyaline, inamyloid, thin-walled. Clamp connections present in all tissues.

Habitat and known distribution:—Gregarious, inserted on leaves in secondary upland forest. Africa ( Príncipe), Brazil, Malaysia, Papua New Guinea, Sri Lanka, Trinidad.

Material examined:—AFRICA. Príncipe, Roça Pico Papagaio, N01˚37.182’, E07˚23.474’, 20 April 2008, D.E. Desjardin and B.A. Perry, BAP 634 (SFSU).

Notes:—The morphology of the Príncipe specimen matches quite closely that of the protologue of M. rorida var. lamprospora ( Corner 1950) , based on material collected in Malaysia, with one exception. The Malaysian type is reported to have a palisade-type pileipellis of clavate-pyriform-pedicellate cells, whereas the West African material has an interrupted cutis to trichodermium with erect terminal cells similar to those described from the holotype. Our material is also nearly indistinguishable from Horak’s (1978) description of M. lamprospora as represented in the southern hemisphere, differing only in pileipellis anatomy. Because of the reported hymeniform pileipellis in M. lamprospora , the species was transferred to the genus Roridomyces , based on R. rorida (Fr.) Rexer , a genus distinguished from Mycena by hymeniform versus cutis-type pileipellis, respectively (Rexer 1994). Both Corner (1950) and Horak (1978) reported the spores as bioluminescent, a feature not observed in the Príncipe specimen. Unfortunately, the sequence data (ITS, LSU) indicate that what we have determined as matching M. lamprospora is distantly related to R. rorida , suggesting that M. lamprospora does not belong in Roridomyces . Alternatively, the Príncipe specimen, which is morphologically more or less indistinguishable from M. lamprospora , does not represent M. lamprospora .

We were able to acquire only 150 base pairs of the ITS region of M. lamprospora (BAP 634) and consequently we did not include it in the ITS phylogeny. The nLSU sequence of M. lamprospora is 92.3% similar with R. rorida , and falls into a poorly supported clade with Panellus stypticus , Cruentomycena viscidocruenta and Roridomyces rorida . Mycena lamprospora was not sister to R. rorida in the tree, indicating that they may not be congeneric. Our recognition of the Príncipe taxon as belonging in Mycena rather than Roridomyces is tentative pending multigene analyses of additional material.

Figures

FIGURE 25. Mycena lamprospora (BAP 634). a. Basidiospores. b. Basidia and basidiole. c. Cheilocystidia of two types. d. Pileipellis terminal cells of two types. e. Caulocystidia. Scale bar = 10 μm.