Studies on the new and dominant species of genus Pythium in Nanning Region of Guangxi

From 1998～2001，172 genus Pythium strains had been found fmm 106 specimens collected in 11 counties of Narming，Cmangxi Zhuang Autonomous Region of China．Among them，Pythium falciforme sp．nov．and P．nanningense sp．nov．are reported here as new species．6 species，namely P．acanthophoron Sideris，P．irregulare Buisman，P ．kunmingense Yu，P ．middletonii Sparrow ，P ．tardicrescens Vanterpo ol and P ．ultimum Trow are new records to this region．P．aphanidermatum(Edson)Fitzpatrick and P．spinosum Sawada are the dominant population．New species are described fully and illustrated ．