Xylodon vesiculosus Yurchenko, Nakasone & Riebesehl

Riebesehl, Janett, Yurchenko, Eugene, Nakasone, Karen K. & Langer, Ewald, 2019, Phylogenetic and morphological studies in Xylodon (Hymenochaetales, Basidiomycota) with the addition of four new species, MycoKeys 47, pp. 97-137 : 97

Xylodon vesiculosus Yurchenko, Nakasone & Riebesehl nom. nov. Figs 3e, 9

Replaced synonym.

Odontia vesiculosa G. Cunn., Transactions and Proceedings of the Royal Society of New Zealand 86(1): 75 (1959) nom. inval.

Typus.

NEW ZEALAND: Otago, Alton Valley, Tuatapere, leg. J.M. Dingley, Feb 1954 (PDD-18112 - holotype).

Cunningham (1959) described this new taxon as Odontia vesiculosa G. Cunn. Earlier, Odontia vesiculosa Burt was used for another species ( Povah 1929). Consequently, Odontia vesiculosa G. Cunn. is an illegitimate name and a new name is required for this taxon (see Art. 6.11, 7.4 and 58.1 in Turland et al. 2018).

Below is a description based on the isotype of X. vesiculosus (CFMR).

Description.

Basidiomata effused, odontioid, membranaceous, with a densely odontioid, ochraceous hymenial surface. Margin mostly abrupt, some parts thinning out. Hymenophoral aculei cylindrical to conical, acute apically, 130-350 μm long, 60-150 μm diam. at base, 4 per mm. Subiculum 100-150 μm thick, minutely cracking. Hyphal system monomitic; hyphae clamped at all primary septa. Subicular and tramal hyphae thick-walled (wall up to 1.5 μm), 2.5-4 μm wide, often with narrow lumen, smooth, colourless, looking faint yellowish in mass due to refractive walls. Subhymenium well developed; hyphae richly branched, thin- to slightly thick-walled, yellowish in mass. Aculei bearing skeletal-like, naked or poorly encrusted, immersed hyphal ends and variously encrusted, thick-walled, projecting hyphae in bunches, 3.5-5 μm wide. Capitate elements common, as lateral branches on tramal or subhymenial hyphae, (25 –)30– 55 × 6.5-10.5 μm, thin- to thick-walled, aseptate or with 1-2 adventitious septa. Basidioles clavate, subcylindrical, utriform. Basidia utriform to subcylindrical and clavate, 15-22 × 4-5 μm, thin-walled, smooth, with four sterigmata ca. 2 × 0.5 μm. Spores ellipsoid to narrowly ellipsoid or short cylindric, 5.3 –6.3(– 7) × 3-4 μm, holotype L = 5.9, W = 3.4, Q = 1.8 (n = 22), with adaxial side flat to convex, smooth, thin-walled, colourless, with minute apiculus, inamyloid, indextrinoid, acyanophilous.

Remarks.

This species was considered conspecific with Xylodon lanatus from North America ( Burdsall and Nakasone 1981, Wu 1990, Gorjón and Greslebin 2012), but we observed significant morphological differences. For example, in X. vesiculosus , the basidiomata have a denser, tough-membranaceous texture compared to the soft woolly basidiomata of X. lanatus . In addition, the aculei in X. vesiculosus are larger and the basidia are thin-walled in contrast to the smaller aculei and basally thick-walled basidia found in X. lanatus (compare Figs 9, 10). See Discussion for a key to X. lanatus , X. vesiculosus and allied taxa.

Xylodon niemelaei (Sheng H.Wu) Hjortstam & Ryvarden, Synopsis Fungorum 26: 28 (2009)

≡ Hyphodontia niemelaei Sheng H. Wu, Acta Botanica Fennica 142:98 (1990).

Xylodon rhizomorphus (C.L.Zhao, B.K.Cui & Y.C.Dai) Riebesehl, Yurchenko & Langer, Mycological Progress 16(6): 649 (2017).

≡ Hyphodontia rhizomorpha C.L.Zhao, B.K.Cui & Y.C.Dai, Cryptogamie, Mycologie 35(1):92 (2014).