Protohydnum galzinii (Bres.) Spirin & R. H. Nilsson, 2025

Spirin, Viacheslav, Malysheva, Vera, Viner, Ilya, Alvarenga, Renato Lúcio Mendes, Grebenc, Tine, Gruhn, Gérald, Savchenko, Anton, Grootmyers, Django, Ryvarden, Leif, Vlasák, Josef, Larsson, Karl-Henrik & Nilsson, R. Henrik, 2025, Additions to the taxonomy of the Auriculariales (Basidiomycota) with pedunculate basidia, MycoKeys 120, pp. 339-392 : 339-392

Protohydnum galzinii (Bres.) Spirin & R. H. Nilsson comb. nov.

Figs 7 D , 11 F

≡ Sebacina galzinii Bres. , Annales Mycologici 6: 46, 1908. Lectotype (selected by Wells and Raitviir 1975: 908). France. Aveyron: Saint-Sernin-sur-Rance , Fraxinus excelsior , V. 1905 Galzin 3832 ( S F 19700 , studied) .

= Bourdotia galzinii (Bres.) Torrend , Brotéria Serie Botanica 11: 88, 1913.

= Bourdotia caesia Bres. & Torrend , Brotéria Serie Botanica 11: 88, 1913. Lectotype (selected here, MBT 10025860 ). Portugal. Lisboa, ‘ ad ligna’, 27.XII.1909 Torrend ( PC 0084209 , studied).

Description.

Basidiocarps effused, covering a few cm, smooth or indistinctly tuberculate, gelatinous, first semitranslucent, bluish-greyish, then opalescent, whitish, 0.1–1 mm thick, in dry condition vinaceous-brown to brownish-black, vernicose, margin gradually thinning-out. Hyphal structure monomitic, hyphae hyaline or yellowish, clamped; subicular hyphae thin-walled, subparallel, 3–4 μm in diam., subhymenial hyphae thin-walled, interwoven or ascending, rather densely arranged, 1.5–3.5 μm in diam. Gloeocystidia abundant, brownish-yellowish, deeply rooted, usually tapering to the apex, often sinuous, embedded, (68 –) 70–109 (– 118) × (4.1 –) 4.2–7.2 (– 8.6) μm (n = 30 / 3). Hyphidia abundant, richly branched, 1–1.5 μm in diam. at the apex, forming a continuous layer up to 20 μm thick. Basidia four-celled, longitudinally or occasionally obliquely septate, ovoid-ellipsoid, pedunculate, (12 –) 13–20 (– 23.5) × (8.7 –) 8.9–13.1 (– 14.0) μm (n = 41 / 4), stalk up to 16 × 2.5–3 μm, sterigmata tubular, gradually tapering, up to 20 × 2–3.5 μm. Basidiospores smooth, thin-walled, ellipsoid-ovoid to broadly cylindrical, the longest spores slightly curved, (8.1 –) 8.3–12.3 (– 12.8) × (5.0 –) 5.1–7.3 (– 7.4) μm (n = 180 / 6), L = 9.32–11.26, W = 6.23–6.48, Q’ = (1.2 –) 1.3–2.0 (– 2.3), Q = 1.49–1.75.

Distribution and ecology.

Europe ( Austria, France, Germany, Italy, Portugal, Russia, Spain, and Ukraine), Macaronesia (Canary Islands), and Asia ( Iran); decorticated wood of deciduous trees, rarely conifers.

Remarks.

This species was first described as a member of the simultaneously introduced subgenus Bourdotia Bres. in the genus Sebacina Tul. & C. Tul. ( Bresadola 1908). Five years later, the subgenus was raised to the genus rank, and another species, B. caesia , was added ( Torrend 1913). We studied type material of both species and concluded that they are conspecific. Here we treat Bourdotia as a synonym of Protohydnum and therefore transfer B. galzinii to the latter genus.

Protohydnum galzinii is a temperate species widely distributed in Europe. Due to its prominent gloeocystidia and stalked basidia, it can be easily identified under the microscope. The identity of B. galzinii collections from North and South America, as well as that of Bourdotia petiolata (D. P. Rogers) K. Wells , originally described from the Marshall Islands, remains obscure due to the lack of recent sequenced material. Bourdotia galzinii f. microcystidiata Hauerslev was described based on a single collection (Galzin 14319, PC) initially identified by Bourdot as Sebacina mesomorpha Bourdot & Galzin ( Hauerslev 1993). We restudied this specimen and concluded that it belongs to Exidiopsis opalea (Bourdot & Galzin) D. A. Reid.

Figures

Figure 7. Microscopic structures of: A. Elmericium alabastrinum (holotype) (1 – hymenial cells and subhymenial hyphae; 2 – subicular hyphae); B. Hydrophana trichiesiana (holotype); C. Protohydnum album (specimen Miettinen 196583); D. P. galzinii (specimen Miettinen 15900.4). Scale bar: 10 µm.

Figure 11. Basidiospores of: A. Protohydnum album (specimen Miettinen 196583); B. P. aureum (holotype); C. P. elasticum (holotype); D. P. elevatum (holotype); E. P. erumpens (holotype); F. P. galzinii (three left – specimen Miettinen 15900.4, three right – lectotype of S. galzinii); G. P. lactescens (four left – specimen TAAM 192048, three right – holotype of S. lactescens); H. P. livescens (specimen Spirin 13913); I. P. microperum (holotype); J. P. nudum (holotype); K. P. ocellatum (holotype); L. P. pallidum (holotype); M. P. pululahuanum (three left – lectotype, three right – specimen FH 00783538); N. P. sucinum (three left – lectotype of A. brasiliensis, three right – specimen BPI 701268); O. Protomerulius amiliavi (holotype); P. P. deceptorius (holotype). Scale bar: 10 µm.