Fasciodontia Yurchenko & Riebesehl, gen. nov.

Index Fungorum number: MB 829454; Facesoffungi number: FoF

Type species: Fasciodontia bugellensis (Ces.) Yurchenko, Riebesehl & Langer, comb. nov. (MB 829456).

Basionym: Odontia bugellensis Ces. in Rabenhorst, Klotzschii Herb. Viv. Mycol. no. 1915, 1855. Typus: Italy, Piemonte, ‘in ligno durissimo Castaneae vetustae reperi Bugellae ao 1850’, leg. V. Cesati [Rabenh., Klotzschii Herb. Viv. Mycol., Cent. 20: no. 1915 (HAL, s.n.), lectotype (MycoBank no.: MBT390118), see a remark below]

Etymology: ‘Fascio’ (Lat.) refers to fasciculate arrangement of hyphae in aculei, ‘dontia’ stresses the derivative origin from Hyphodontia s.l.

Description: Basidioma effused, membranaceous, cracking with age; margin thinning out, rarely abrupt. Hymenial surface minutely odontioid, whitish or cream-colored; aculei sterile except bases and consisting of projecting hyphae. Hyphal sys- tem pseudodimitic; hyphae clamped at all primary septa, col- orless in water, slightly yellowish in mass in KOH, moderate- ly cyanophilous, negative in Melzer’s reagent; skeletal-like thick-walled hyphae present in basal subhymenium and in aculeal trama; skeletal-like hyphae in aculei loosely encrusted, apically thin-walled, partly agglutinated with age. Cystidia from cylindrical to slightly moniliform and capitate. Basidia utriform to subcylindrical, with two slight constrictions, thin- walled or slightly thick-walled in lower 1/2–2/3, with four sterigmata. Spores ellipsoid, smooth, with thickened or thick wall (about 0.2–0.3 μm thick), colorless, negative in Melzer’s reagent, slightly to moderately cyanophilous.

Distribution and ecology: The species of the genus are known from Europe, Canary Islands, Africa (Hjortstam and Ryvarden 2007a), East Asia, South America, and grow on dead wood.

Remarks: The main diagnostic features of the genus are mi- nutely odontioid hymenophore, presence of thick-walled skele- tal-like hyphae, associated with aculeal trama, submoniliform cystidia, which are from seldom to numerous, confined mostly to the base of aculei, and thick-walled basidiospores. Xylodon is the closest genus to Fasciodontia in both morphological and molecular aspects. However, the species of Xylodon with thick- walled spores [X. brevisetus, X. capitatus (G. Cunn.) Hjortstam & Ryvarden, X. detriticus, X. rickii (Hjortstam & Ryvarden) Riebesehl & Langer, and X. septocystidiatus (H.X. Xiong, Y.C. Dai & Sheng H. Wu) Riebesehl & Langer] lacked the combina- tion of characters listed above. Xylodon crassisporus (Greslebin & Rajchenberg) Hjortstam & Ryvarden has spores, basidia, cystidia, and pseudoskeletal hyphae in teeth similar with Fasciodontia. However, this species possesses capitate cystidia with yellowish resinous caps (Greslebin and Rajchenberg 2000). Hyphodontia sinensis H.X. Xiong, Y.C. Dai & Sheng H. Wu has hyphae, structure of aculeal trama, and basidiospores somewhat similar with Fasciodontia. In the same time, H. sinensis has long- cylindrical, thin-walled embedded cystidia (Xiong et al. 2010), which are not peculiar to Fasciodontia. The exact taxonomic position of X. crassisporus and H. sinensis will be stated only after their DNA sequences will be available.

Publication of the new species Odontia bugellensis was based on exsiccata “Herbarium Vivum Mycologicum” distributed and stored in several herbaria, with no indication of a solitary holotype. In this study, we have selected and designated as lectotype an exsiccatum stored in HAL (see Braun 2018). Microscopic exami- nation of this material showed the main diagnostic features of

F. bugellensis: cracking odontioid basidioma, constricted cystidia, and thick-walled spores; L = 6.07 μm, W = 4.12 μm, and Q = 1.48.


  • Fasciodontia bugellensis