Protohydnum sucinum (Möller) Spirin & Alvarenga 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 sucinum (Möller) Spirin & Alvarenga comb. nov.

Figs 10 D , 11 N

≡ Exidia sucina Möller , Botanische Mittheilungen aus den Tropen 8: 169, 1895. Lectotype (selected here, MBT 10025864 ). Brazil. Santa Catarina, Blumenau , [1892] Möller 8 ( HBG, studied).

= Auricularia brasiliensis Lloyd , Mycological Writings 5: 785, 1918. Lectotype (selected here, MBT 10025884 ). Brazil. [no locality and collecting date], Rick (Lloyd’s herbarium # 33208) ( BPI 701266 , studied).

Description.

Basidiocarps pulvinate or cerebriform, up to 1 cm in diam., occasionally fusing together and producing compound fructifications up to 4 cm in widest dimension, gelatinous, semitranslucent, pale ochraceous or amber-coloured to brownish-orange, 1.5–8 mm thick, in dry condition brown and tough, margin elevated, partly detaching; lobes rounded, blunt, entire, up to 1.5 mm thick. Hyphal structure monomitic, hyphae hyaline or yellowish, clamped, thin-walled or with a distinct wall; context hyphae predominantly interwoven, 1–3 μm in diam., occasionally inflated up to 6 μm in diam., embedded in gelatinous matrix, subhymenial hyphae ascending, rather loosely arranged, 1–3 μm in diam. Gloeocystidia abundant, brownish, distinctly tapering at the apex, sometimes subulate, embedded or variably projecting, (75 –) 80–248 (– 272) × (4.0 –) 4.2–10.6 (– 11.1) μm (n = 30 / 4). Hyphidia hyaline to brownish, richly branched, 0.5–1 μm in diam. at the apex, forming a continuous layer up to 50 μm thick. Basidia four-celled, longitudinally or obliquely septate, ovoid-ellipsoid, sessile or rarely with a strongly reduced stalk up to 4 × 3 μm, (11.5 –) 12–16.5 (– 17) × (7.8 –) 8.1–12.4 (– 13.7) μm (n = 40 / 4), sterigmata gradually tapering, up to 30 × 3–4 μm. Basidiospores smooth, thin-walled, cylindrical to broadly cylindrical, usually slightly curved (bean-shaped), (8.3 –) 8.8–11.0 (– 11.1) × (4.7 –) 4.8–6.1 (– 6.3) μm (n = 120 / 4), L = 9.99–10.75, W = 5.23–5.53, Q’ = (1.5 –) 1.6–2.4 (– 2.6), Q = 1.83–1.99.

Distribution and ecology.

South America (southern part of Brazil); decayed wood of angiosperms.

Remarks.

The authentic specimen of E. sucina , as well as many other of Möller’s collections, was noted as being present in the HBG herbarium by Friedrichsen (1977) but never properly investigated. We studied it and formally designated the specimen as a lectotype of E. sucina . Morphologically, P. sucinum is most similar to P. lactescens ; their differences are listed under that species. Three original specimens of Auricularia brasiliensis (all collected by Rick in Brazil) in Lloyd’s herbarium (BPI) belong to P. sucinum sensu typi; we therefore place A. brasiliensis among the synonyms of P. sucinum . No modern specimens of P. sucinum are known to us.

Figures

Figure 10. Microscopic structures of: A. Protohydnum lactescens (specimen TAAM 192048) (hymenial cells and tramal hyphae); B. P. livescens (specimen Spirin 13913) (hymenial cells and subhymenial hyphae); C. P. pallidum (holotype) (gloeocystidia and a basidium); D. P. sucinum (lectotype) (1 – basidia and basidiospores; 2 – gloeocystidia). 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.