Taxonomic Studies Of Two Hyphomycete Genera, Ulocladium Preuss And Stemphylium Wallr. In China

The content of this study is about the taxonomic research of Ulocladium Preuss and Stemphylium Wallr. in China. 138 isolates were received from the 3500 specimens of leaf spots and rotten woods, which we collected from Sichuan, Chongqing, Yunnan, Guizhou, Hunan, Jilin, Liaoning, Heilongjiang, Hebei, Jiangsu, Shandong Provinces, Xinjiang Autonomous Region in China and Paris, Angres, Nantes in France. We also observed several specimens from CBS.We found and described 19 species, seven new species are S. capsici Yong Wang bis et X.G. Zhang, sp. nov., S. plantaginis Yong Wang bis et X.G. Zhang, sp. nov., S. pruni Yong Wang bis et X.G. Zhang, sp. nov., S. oblongum Yong Wang bis et X.G. Zhang, sp. nov., S. sophorae Yong Wang bis et X.G. Zhang, sp. nov., U. bassicae Yong Wang bis et X.G. Zhang, sp. nov., and U. subcucurbitae Yong Wang bis et X.G. Zhang, sp. nov.; 2 new records in China are S. lancipes E.G. Simmons and U. dauci E.G. Simmons. Other 10 species, Which have been reported in China, are S. botryosum Wallr., S. globuliferum (Vestergren) E. G. Simmons, S. lycopersici (Enjoji) W. Yamamoto, S. nabarii M. Sarwar & K.V. Srinath, S. vesicarium (Wallr.) E.G. Simmons, U. alternaria (Cooke) E.G. Simmons, U. atrum Preuss, U. botrytis Preuss, U. chartarum (Preuss) E.G. Simmons, and U. consortiale (Thüm.) E.G. Simmons.Our results are generally congruent with Simmons'treatment of Ulocladium. Nevertheless, it appears that ulocladioid spores scattered unobtrusively among conidia (7 d) are relatively variable, or atypical, whereas those of late growth (15 d) are abundant, and definitive. We would therefore propose that isolates of Ulocladium should be examined late-growth sporulation to provide additional species-differential data.For this reason, early-stage conidia, absent consideration of late-stage sporulation, should not be considered to be uniquely definitive of Ulocladium species. Thus, the conidial characters of these two stages (early-stage and late-stage) may both be helpful in keying the taxa treated here. This study therefore underlines that the correct identity of Ulocladium spp. must be based on a standardized approach.The taxonomic criteria of Ulocladium and Stemphlium species mainly base on the shape of conidia, the conidia septum and the existence of secondary conidiophore and secondary conidia. Some parameter such as the size range of conidia, is rather important in division some species which had similar conidial shape. The host and culture character is less useful in dealing with these two genera. Meanwhile, we, d better combine the classical taxonomy with the molecular technologies in order to keep the rightness of identification.