Taxonomic Studies Of Dematiaceous Hyphomycetes On Decaying Wood In Southern China And Yunnan Province Tropical And Subtropical Regions Of China

The wood-inhabiting microfungi are very abundant and widely distributed in the nature. These fungi play an important ecological role in the decomposition and recycling of materials in natural ecosystems. There is economic and ecological significance to study these fungi. Abundant decaying wood and dead branches in the tropical and subtropical regions of China support a high level of dematiaceous hyphomycetes diversity. This study mainly aims at the taxonomic research of dematiaceous hyphomycetes on decaying wood collected in the tropical and subtropical regions of southern China and Yunnan Province.During the investigations of conidial fungi from2009to2012, we collected more than1000specimens from different ecological regions in Hainan, Guangdong, Hunan and Yunnan Provinces. We have discovered quite a few new and noteworthy taxa and achieved many aluable results based on the careful identification. Two new genera, Cladosporiopsis Sh.C Ren&X.G. Zhang and Sativumoides Sh.C. Ren, Jian Ma&X.G. Zhang are established. One newly recorded genus from China, Xenoheteroconium Bhat, W.B. Kendr.&Nag Raj is introduced. Add up to91taxa included in24genera of dematiaceous hyphomycetes arc described, illustrated, and compared with closely related taxa.Among them,21taxa are proposed to new species, they are Cladosporiopsis ovata Sh.C Ren&X.G. Zhang, Corynesporopsis chukrasiae S.C. Ren&X.G. Zhang, Dischloridium elliptia Sh.C. Ren&X.G. Zhang, Ellisembia annesleae S.C. Ren&X.G. Zhang, E. heritierae S.C. Ren&X.G. Zhang, E. hernandiae S.C. Ren&X.G. Zhang, E. rostrata S.C. Ren&X.G. Zhang, Endophragmiella micheliae S.C. Ren&X.G. Zhang, E. nanlingensis S.C. Ren&X.G. Zhang, Exserticlava manglietiae S.C. Ren&X.G. Zhang, Heleroconium annesleae S.C. Ren&X.G. Zhang,H. fusiformis S.C. Ren&X.G. Zhang, H. neolitseae S.C. Ren&X.G. Zhang, Repelophragma ellipsoidea S.C. Ren&X.G. Zhang, R. euryae S.C. Ren&X.G. Zhang, R. hainanensis S.C. Ren&X.G. Zhang, Sativumoides punicue Sh.C. Ren, Jian Ma&X.G. Zhang. Solicorynespora rostrala S.C. Ren&X.G. Zhang, Spiropes ovata S.C. Ren&X.G. Zhang. S. terminaliae S.C. Ren&X.G. Zhang, Sporidesmium yunnanense S. C. Ren&X.G. Zhang.20species arc newly recorded to China:Acrodiclys elaeidicola M.B. Ellis, A. septosporioides Matsush., Corynespora calicioidea (Berk.&Broome) M.B. Ellis, C. gigaspora (Berk.&Broome) M.B. Ellis, C. homaliicola Deighton&M.B. Ellis, C. lanneicola Deighten&M.B. Ellis, Corynesporopsis isabelicae Hol.-Jech., C. cylindrica B.C. Sutton, Curvularia prasadii R.E. Mathur&B.L. Mathur, Diplococcium stoveri (M.B. Ellis) R.C Sinclair, Eickcr&Bhat, Dischloridium inaequiseplata (Matsush.) Hol.-Jech., D. laeense (Matsush.) B. Sutton, D. triseptatum Hol.-Jech., Ceska Mykol, Endophragmiella corticola P.M. Kirk, E. pulchra (B. Sutton&Hodges) P.M. Kirk, E. resinae P.M. Kirk, E. rostrata P.M. Kirk, E. laxi (M.B. Ellis) S. Hughes, Solicorynespora mulanjeensis (B. Sutton) R.F. Castaneda, M. Stadler&Guarro, S. pseudolmediae (R.F. Castaneda) R.F. Castaneda&W.B. Kendr., Sporidesmium acutisporum M.B. Ellis, Xenoheteroconium bieolor Bhat, W.B. Kendr.&Nag Raj.1taxon, Ellisembia manuensis (Matsush.) S.C. Ren&X.G. Zhang is proposed to new combination.49taxa are described as reported species from China. All specimens are deposited in the Herbarium of the Department of Plant Pathology, Shandong Agricultural University (HSAUP).Based on our studied works, some useful taxonomic methods, criterias and viewpoints concerning this group of fungi were concluded:1. Most of decaying wood dematiaceous hyphomycetes are saprophytic. Their conidial morphology and size are accessible to the culture condition and culture media, and different from those surviving on the natural substrates. During the long-term evolutionary process in nature, wood-inhabiting dematiaceous hyphomycetes have formed more constant morphological characteristics. Therefore, the morphology of these fungi on the natural substrates should be primary identifying bases, while culture features can be used essential supplements and assistances.2. At genus level of taxonomic criteria, the patterns of conidial formation and conidiophores (conidiogenous cells) proliferation are the main criteria to separate different genera. To differentiate those genera having same patterns of conidial formation and conidiophores proliferation, the type of septum, the order of septum ontogenyand and the morphological characters of conidiogenous cells should be considered. Conidiophores and patterns of conidia germination also play very important roles. Sometimes, the conidial inserted characteristics (solitary or catenate) is the only criterion to separate few genera. In addition, the characters, color and growth traits of colonies are assistant to distinguish some genera.3. At species level of taxonomic criteria, the morphological characteristics of conidia, especially the shape, size, septum, appendage, rostrate, color and ornamentation arc main diagnostic characteristics. The features of conidiophores (conidiogenous cells) proliferation is sometimes used to differentiate species in some genera. Moreover, stromata are presence or not, branched or simple and the size of conidiophores are different among some species, which can be one of taxonomic criteria at species level.Fungal classification and identification is a quite complex process, and all kinds of taxonomic criterias should be considered generally, and depend on various taxonomic mathods. It is necessary to observe the overall characteristics, but also concern on local features, and not only concert on their common characteristics, but also focus on their essential differences.