Identification Studies On Fallen Dead Wood Dematiaceous Hyphomycetes From Five Provinces In South Of China

Southern China is a unique geographical area where have complex terrains and notable altitude difference. It spans several climate zones, covers much tropical and subtropical forest ecosystems, all of the sampled regions are characterized by high humidity, high mean temperature. The vegetation is composed mostly of trees, and there is a deep litter layer comprising rotten softwood, dead branches, and decay leaves of various plants. Dead wood are a rich habitat for hyphomycetes. This study aimed to survey the population of dematiaceous hyphomycetes from decay wood on genus and species level from south of China and utilize and protect the species diversity of China.A total of1000specimens were collected from many representative sites in Sichuan, Guangdong, Guangxi, Yunnan and Hainan provinces. The specimens were brought back to the laboratory in the sterile plastic bags and were examined directly while it is still fresh and moist under the dissecting microscope or incubated in the moist boxes. From these collections,25taxa at species level are described and illustrated which belong to17genera. Among them,8taxa are identified as new species,5taxa are regard as the new records for China,12taxa have been reported in China. All genera and species are fully described and illustrated morphologically.8taxa are new species. They are Corynesporella bannaense J.W. Xia&X.G. Zhang、 Corynesporopsis curvularioides J.W. Xia&X.G. Zhang、Heteroconium bannaense J.W. Xia&X.G. Zhang、Minimelanolocus bicolorata J.W. Xia&X.G. Zhang、Paradendryphiopsis elegans J.W. Xia&X.G. Zhang、Spadicoides bawanglingensis J.W. Xia&G.X. Zhang、 Spadicoides longchiensis J.W. Xia&X.G. Zhang、Sporidesmiopsis guangxiensis J.W. Xia&X.G. Zhang。5species having been previously reported from China are redescribed and discussed. They are Brachysporiellina pulneyensis Subram.&Bhat、Gangliostilbe indica Subram.&Vittal、Guedea novae-zelandiae Hughes、Heteroconium arundicum Chowdhry、Kylindria excentrica Bhat&B. Sutton.12species are known to China:Brachysporiella gayana Bat、Brachysporiella pulchra (Subram.) S. Hughes、Corynesporopsis liquidambaris Jian Ma&X.G.Zhang、Helicoma palmigenum (Penz.&Sacc.) Linder、Heteroconium decorosum R.F. Castaneda, Saikawa&Guarro、Spadicoides bambusicola D.Q. Zhou, Goh&K.D. Hyde、Sporidesmiopsis dennisii (J.L. Crane&Dumont) Bhat, W.B. Kendr.&Nag Raj、Taeniolina schimae Y. D. Zhang&X. G. Zhang、Stanjehughesia larvata (Cooke&Ellis) Subram.、Stanjehughesia vermiculata (Cooke) Subram.、Stephembruneria elegans R.F. Castancda、Synnemacrodictys stilboidea (J. Mena&Mercado) W. A. Baker&Morgan-Jones.All specimens examined are deposited in the Herbarium of the Department of Plant Pathology, Shandong Agricultural University (HSAUP) and Mycological Herbarium, Institute of Microbiology, Chinese Academy of Sciences (HMAS).Anamorphic fungi is an independent taxonomical group, its taxonomic studies is mainly based on morphological characteristics of the asexual stage. However, the criteria used for genera or species delimitation has a difference due to mycologist keeping different taxonomical views. Based on continuing study of dematiaceous hyphomycetes occurring on dead branches, and carefully reading many documents, we summarized and put forward the criteria of taxonomic studies of dead wood dematiaceous hyphomycetes.①The taxonomic classification of dematiaceous hyphomycetes that sap robes on dead branches or rotten wood should be mainly based on the morphological characteristics from the natural substrates. Culture feature and sporulation pattern can be used as a necessary complement for identification.②The type of conidiomata, the method of extension of conidiogenous cells/conidiophores, and conidiogenous pattern are key to distinguish hyphomycetes at genus level; the characteristics of conidiogenous loci, the mode of conidial secession (schizolytic/rhexolytic) and outstanding features such as euseptation/distoseptation, solitary/catenate are occasionally used as the criteria for identification at generic level; the branching pattern of conidiophores, shape of conidiogenous cells, presence of sterile setae and stroma, and other features are also useful to distinguish a few genera.③Conidial morphology including shape, size, pigmentation, septation, ornamentation and appendage are the basic criteria in distinguishing species. Among similar species, the common, outstanding conidial morphological characteristics are also help with genera circumscribed. The presence or absence, the forming sequence and position of septation are also considered as one of criteria in distinguishing species or genera for different species or genera that have stable differences.④For the criteria of distinguishing species, conidial shape, conidial size and septation are regarded as primary criteria, and conidial appendage, pigmentation and ornamentation are usually as second criteria.