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).