Amphisphaeriales » Oxydothidaceae



Oxydothis Penz. & Sacc., Malpighia 11(11-12): 505 (1898) [1897]

Xylariomycetidae, Amphisphaeriales, Oxydothidaceae, Oxydothis

Index Fungorum number: IF3661; 79 morphological species; 12 species with sequence data.


Saprobic, endophytic or parasitic on monocotyledons. Sexual morph: Ascomata solitary or irregularly scattered, ellipsoidal or subglobose, immersed or semi-immersed, slightly raised from host surface with light or darkened discs, with most taxa lying horizontal to the host surface. Peridium thick-walled, brown to dark brown, and/or peridium cells merging with the host tissue. Paraphyses hypha-like, filamentous, irregular, septate, persisting between asci, but often fragmenting in dried material. Asci 8-spored, unitunicate, cylindrical, pedicellate, with a J+ (rarely J-), subapical ring. Ascospores fasciculate, hyaline, sometimes appearing yellow in mass, fusiform or filiform, 1-septate, tapering from the center to spine-like, pointed or rounded ends. Appressoria produced by germinating ascospores in some species, solitary, hyaline or greenish, or pale brown to brown, irregular in shape, thick-walled. Asexual morph: Hyphomycetous. Selenosporella sp. Conidiophores mononematous, (1–)2–3-septate, unbranched or 1-branced, brown olivaceous, thick-walled at below, thin-walled and colourless above, unicellular, colourless, distinct obviously differentiated apex or base (adapted from Samuels & Rossman 1987, Konta et al. 2016).


Type species: Oxydothis grisea Penz. & Sacc., Malpighia 11(11-12): 505 (1898) [1897]


Notes: Oxydothis was described from Cibodas, Java, Indonesia by Penzig & Saccardo (1897) with three species O. grisea, O. nigricans and O. maculosa, and placed in Amphisphaeriaceae (sensu Eriksson & Hawksworth 1991). The genus is characterized by two types of ascomata, one is developed singly or in clusters, in darkened, ellipsoidal raised areas on the host surface, and have distinctive eccentric ostioles, whereas another are those developed below a raised sheet of host epidermis, and usually not darkened (Fröhlich & Hyde 2000). Hyde reviewed the taxa of Oxydothis and emphasized that ascus and ascospore morphology in this genus is consistent and reliable for distinguishing species, and also discussed the morphology of closely related genera, Ceriospora, Frondispora, Lasiobertia and Leiosphaerella (Hyde 1993, 1994). However, the familial classification of this genus was uncertain and it had been placed in Hyponectriaceae (Hyde 1993) and Clypeosphaeriaceae (Kang et al. 1999) based on morphology. Jeewon et al. (2003) analysed DNA sequence data and mentioned that Oxydothis was closely related to Leiosphaerella (Xylariales, genera incertae sedis), and Konta et al. (2016) placed the genus in Oxydothidaceae (Xylariales). Konta et al. (2016) also suggested that Oxydothis species may be associated with healthy plants as endophytes and become saprobes, based on their observations of appressoria.




Species illustrated in this entry:

Oxydothis phoenicis S.N. Zhang, K.D. Hyde & J.K. Liu



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The webpage Sordariomycetes provides an up-to-date classification and account of all genera of the class Sordariomycetes.


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