Clitocybula intervenosa A.C. Cooper, Desjardin & B.A. Perry, 2018

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 : 34-36

15. Clitocybula intervenosa A.C. Cooper, Desjardin & B.A. Perry , spec. nov. ( Figs. 26 , 27 )

MycoBank no.: MB 825516

Holotype:—AFRICA, São Tomé, Parque Nacional Obo , Lagoa Amelia Trail between N 00˚17.112’, E06˚35.967 ’ and N 00˚16.922’, E06˚36.062 ’, 14 April 2008, D. E. Desjardin and B. A. Perry, BAP 613 ( SFSU).

Etymology:— intervenosa – referring to the strongly intervenose lamellae.

Diagnosis:— Pileus 6–25 mm diam, broadly convex to campanulate, umbilicate or with a central depression, margin striate, becoming upturned, flared and eroding in age; surface glabrous, moist, watery brownish grey (7–8C–D3), hygrophanous, becoming pallid grey overall with moisture loss. Context thin, concolorous with pileus. Lamellae decurrent to deeply decurrent, close to subdistant (12–21) with 1–2 series of lamellulae, highly intervenose to forked, narrow, pale grey. Stipe 8–30 × 1–2.5 mm, central, terete or flattened, cylindrical or broadened towards base, occasional tapered in mid-section, solid; surface smooth, glabrous, pale grey, some with pale brown tones towards base, base with or without white mycelium. Odour and taste indistinct. Bioluminescence undetected.

Basidiospores 5.6–7.2 (–8.8) × (3.2–) 4.0–4.8 (–5.6) μm [x mr = 6.5–6.8 × 4.4–4.5 μm, x mm = 6.65 ± 0.2 × 4.47 ± 0.1, Q = 1.2–2.3, Q mr = 1.48–1.52, Q mm = 1.50 ± 0, n = 19–20, s = 2], ellipsoid to lacrymoid, smooth, hyaline, amyloid, thin-walled. Basidia 21.6–38.4 × 5.6–7.2 μm, clavate, hyaline, inamyloid, thin-walled, 4-spored, sterigmata up to 5.6

μm long. Basidioles clavate. Lamellar edge fertile. Cheilocystidia absent or undifferentiated. Pleurocystidia absent.

Pileipellis a cutis; hyphae 0.8–12.0 μm diam, repent, cylindrical, non-diverticulate, hyaline, inamyloid, thin-walled,

non-gelatinous. Hypodermium composed of inflated cells up to 16.0 μm diam, smooth, hyaline, inamyloid to weakly dextrinoid, thin-walled, rare to numerous laticiferous hyphae up to 4.0 μm diam with knob-like projections 4.8–10.4 ×

2.4–3.2 μm. Hymenophoral trama subregular; hyphae 2.0–12.8 μm diam, hyaline, weakly dextrinoid, non-gelatinous,

thin-walled. Stipitipellis a cutis; cortical hyphae 2.4–16.0 μm diam, parallel, cylindrical, hyaline, dextrinoid, thinwalled; medullary hyphae 2.4–16.8 μm diam, smooth, dextrinoid, thin-walled, occasional laticiferous hyphae up to 6.4

μm diam with knob-like projections. Caulocystidia abundant; 8.0–36.0 × 6.4–15.2 μm, versiform, fusiform-clavate or irregular in outline, hyaline, inamyloid, thin-walled. Clamp connections present in all tissues.

Habitat and known distribution:—Densely cespitose on decaying hardwood in primary forest. ( São Tomé).

Additional material examined:—AFRICA. São Tomé, Bom Sucesso Botanical Garden, N00˚17.317’, E06˚36.746’, 11 April 2008, B.A. Perry, BAP 588 (SFSU).

Notes:— Clitocybula intervenosa is characterized by convex-umbilicate, striate, pale brownish grey pileus, pale grey, decurrent, strongly intervenose lamellae, amyloid, ellipsoid basidiospores with mean 6.6 × 4.5 μm, an absence of cheilocystidia, small, versiform caulocystidia, and cespitose habit on decaying hardwood in primary forest.

Clitocybula intervenosa shows some similarities to C. omphaliformis Pegler , described from Tanzania, but the latter forms more crowded, non-intervenose lamellae, smaller subglobose basidiospores (mean 5 × 3.5 μm), cylindrical to lageniform cheilocystidia, and larger caulocystidia (Pegler 1977). Clitocybula grisella (G. Stev. & G.M. Taylor) E. Horak , described from New Zealand, differs in forming adnate to sinuate, non-intervenose lamellae, subglobose basidiospores 4.5–7.0 μm diam, cylindrical cheilocystidia, relatively large pileocystidia, and growth on wood of Nothofagus (Stevenson 1965) . Clitocybula lenta (Maire) Malençon & Bertault , described from Mauretania, has a dirty brown, fibrillose-rimose pileus, reminiscent of an Inocybe , non-intervenose lamellae, and clavate to fusiform cheilocystidia ( Maire 1928).

Pairwise comparisons of aligned, overlapping ITS sequences of C. intervenosa (BAP 588, BAP 613) with the top ten BLAST results show 95.9% similarity to two sequences determined as C. aff. lacerata (KY242502, FJ596916). Clitocybula lacerata (Scop.) Métrod , a north temperate species, shares basidiospore size and lack of cheilocystidia, but differs from C. intervenosa in forming larger basidiomata with a non-striate, radially fibrillose pileus 20–60 mm diam, close, non-intervenose lamellae, and cylindrical to clavate pileocystidia ( Bigelow 1973, Ludwig 2001). Clitocybula intervenosa is sister to C. lacerata in the ITS phylogeny ( Fig. 2) with low support.

Figures

FIGURE 26. Basidiomata of Clitocybula intervenosa a. BAP 588. b. BAP 613 (Holotype). Scale bar = 10 mm.

FIGURE 27. Clitocybula intervenosa (BAP 613, Holotype a–c, BAP 588 d–f). a,d. Basidiospores. b,e. Basidia and basidioles. c,f. Caulocystidia. Scale bar = 10 μm.