Taxonomic Studies On Fallen Dead Wood Dematiaceous Hyphomycetes From Six Provinces In 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 of 900 specimens 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, 26 taxa at species level are described and illustrated which belong to 18 genera. Among them, 3 taxa are identified as new species, 5 taxa are regard as the new records for China, 18 taxa have been reported in China. All genera and species are fully described and illustrated morphologically.3 taxa are new species. They are Blastophragma chongqingense J.M. Gao & X.G. Zhang?Helicoma jianfenglingensis J.M. Gao & X.G. Zhang?Pseudoacrodictys ambigua J.M. Gao & X.G. Zhang?5 new Chinese record species. They are Bahusutrabeeja angularis V. Rao & de Hoog?Cubasina albofusca R.F. Casta?eda?Domingoella albiziae M.B. Ellis?Pseudoacrodictys magnicornuata Fiuza?Pseudodictyosporium wauense Matsush.?Uberispora tropicalis Bhat & W.B. Kendr.?18 Chinese known species. They are Acrophragmis coronata Kiffer & Reisinger?Anacacumisporium appendiculatum Y.R. Ma & X.G. Zhang ?Arachnophora fagicola Hennebert ? Brachysporiella pulchra(Subram.) S. Hughes ?Brachysporiella gayana Bat.?Brachysporiella setosa(Berk. & M.A. Curtis) M.B. Ellis?Ceratosporella stipitata(Goid.) S. Hughes?Dictyoceratosporella cordata Y.R. Ma & X.G. Zhang ? Digitoramispora caribensis R.F. Casta?eda & W.B. Kendr. ?Digitoramispora tambdisurlensis Pratibha ? Melanocephala australiensis(G.W. Beaton & M.B. Ellis) S. Hughes?Pseudodictyosporium wauense Matsush.?Pseudoacrodictys deightonii(M.B. Ellis), W.A. Baker & Morgan-Jones?Repetophragma goidanichii(Rambelli) W.P. Wu?Repetophragma inflatum(Berk. & Ravenel) W.P. Wu?Sporidesmium antidesmatis Jian Ma & X.G. Zhang?Sporidesmium parvum(S. Hughes) M.B. Ellis?Uberispora formosa Jian Ma & X.G. Zhang?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.(1) The taxonomic classification of dematiaceous hyphomycetes that saprobes 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.(2) The 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.(3) Conidial 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.(4) For 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.