Mycena, Cooper, Alexandra C., Desjardin, Dennis E. & Perry, Brian A., 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 : 18-19

5. Mycena antennae A.C. Cooper, Desjardin & B.A. Perry, spec. nov. ( Fig. 11 )

MycoBank no.: MB 825512

Holotype:—AFRICA. São Tomé, Macambrara radio antenna area, elevation 1300 m, N00˚16.557’, E06˚36.326’, 25 April 2008, D.E. Desjardin and B.A. Perry, BAP 660 ( SFSU).

Etymology:— antenna (L.) = a sailyard – a branched structure used to receive radio waves; referring to the antenna-shaped caulocystidia and the site where the holotype was collected, Macambrara radio antenna area.

Diagnosis:— Pileus 2–3 mm diam, broadly convex, margin fimbriate, pellucid-striate; surface glabrous, disc with tiny dark brown spots, off-white elsewhere. Lamellae ascending, adnexed, subdistant with 1–2 series of lamellulae, white; edge concolorous. Stipe 7–22 × <0.5 mm, central, terete, cylindrical, arising from a small basal disc (0.5 mm diam) densely covered with short white hairs; surface minutely white-pubescent, off-white, developing brown tones in age. Odour and taste indistinct. Bioluminescence undetected.

Basidiospores (7.2–) 8.8–10.5 × 3.2–4.8 μm [x m = 9.16 ± 0.71 × 4.52 ± 0.47 μm, Q = 1.67–2.75, Q m = 2.05 ± 0.1, n = 20, s = 1], elongated-ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 11.2–15 × 8.8–10.4 μm, clavate, hyaline, inamyloid, thin-walled, 4-spored, sterigmata up to 3.2 μm long. Basidioles clavate. Lamellar edge fertile. Cheilocystidia abundant, scattered; 8.8–27 × 5.8–14 μm, clavate, apically spinulose, hyaline, inamyloid, thin-walled; spinulae 1.6–5.6 × ≤0.8 μm. Pleurocystidia absent. Pileipellis a cutis; hyphae 7.2–15 μm diam, repent, cylindrical, densely spinulose, hyaline, inamyloid, thin-walled, non-gelatinous; spinulae 0.5–2 × 0.5 μm, cylindrical. Hypodermium undifferentiated. Pileus trama hyphae 5–25 μm diam, cylindrical to slightly inflated, hyaline, inamyloid, thin-walled. Hymenophoral trama subregular; hyphae 2.4–5.6 μm diam, hyaline, inamyloid, non-gelatinous, thin-walled. Stipitipellis a cutis; cortical hyphae 2.4–5.6 μm diam, parallel, cylindrical, smooth, hyaline, dextrinoid, thin-walled; medullary hyphae 8.8–22 μm diam, smooth, dextrinoid, thin-walled, numerous laticiferous hyphae up to 4 μm diam with occasional knob-like projections 5.6–6.4 × 1.6–3.2 μm. Caulocystidia numerous; 8.0–114 × 1.6–6.4 μm, irregularly cylindrical with a broader base, seldom geniculate, with apical finger-like projections, hyaline, inamyloid, thin-walled; apical projections 1.6–11.2 × 0.8–2.4 μm. Clamp connections present in all tissues.

Habitat and known distribution:—Gregarious on sticks in upland secondary forest. ( São Tomé). Only known from the holotype.

Notes:— Mycena antennae is characterized by a unique combination of features, including: a tiny, glabrous, white pileus with dark brown spots on the disc, ascending, adnexed white lamellae, a pubescent white stipe that arises from a small basal disc, inamyloid, elongate-ellipsoid basidiospores with mean 9.2 × 4.5 μm, apically spinulose, clavate cheilocystidia, no pleurocystidia, a cutis-type pileipellis of densely spinulose hyphae, non-dextrinoid pileipellis and lamellar trama tissues, smooth stipitipellis cortical hyphae, irregularly cylindrical caulocystidia with apical diverticula, and growth on sticks. The closest currently accepted infrageneric taxon in which M. antennae could be grouped is M. sect. Granuliferae Maas Geest. & de Meijer (1997). The two known members of this section, viz., M. granulifera Maas Geest. & de Meijer and M. sertipes Maas Geest. & de Meijer , differ in growing on leaves, having much narrower basidiospores (2.7–3.6 μm, Q = 3.2), adnate to arcuate lamellae, and different caulocystidia. Mycena antennae shows many similarities to M. longinqua of sect. Polyadelphia , especially the unusual caulocystidia, but the latter species has amyloid basidiospores, 2-spored basidia, dextrinoid tramal tissues, and lacks clamp connections.

Pairwise comparisons of aligned, overlapping ITS sequences of M. antennae (BAP 660) with the top ten BLAST results indicate 92.6% similarity to a sequence of M. amicta (DQ490645) and 91.8–92% similarity to three sequences of M. illuminans . In the ITS phylogeny ( Fig. 2), M. antennae belongs in a heterogeneous clade with members of sects. Exornatae , Polyadelphia , Longisetae and Sacchariferae . There are no available sequences from other members of sect. Granuliferae .

Figures

FIGURE 11. Mycena antennae (BAP 660, Holotype).a. Basidiospores.b. Basidia.c. Cheilocystidia.d. Pileipellis hyphae.e. Caulocystidia. Scale bar = 10 μm.