中文摘要：

对7种串珠藻属植物共13样本的cox2-3spacer序列进行了测定,并对其进行了系统发育分析.结果表明：cox2-3spacer序列片段长度为415bp,无插入或缺失,核苷酸变异位点238个,占序列长度的57%,其中178个简约信息位点,占序列长度的43%.A-T含量较多,进化上有碱基偏好性.胶串珠藻作为串珠藻属的模式种独立于其他串珠藻属植物,单独位于一个分支;长柄串珠藻、洪洞串珠藻和弧形串珠藻应该归入Sect.Helminthoidea;弯形串珠藻和绞扭串珠藻应归入新属Kumanoa.

英文摘要：

Seven species of Batrachospermum from 13 locations,China are studied,and the cox2-3 spacer sequences are used to determine the phylogenetic relationship of these taxa.The results showed that the cox2-3 spacer region from all species sequenced was 415 bp with no base pair substitutions or insertion/deletions.There were 238 variation sites（57%） and 178 parsimony informative site（43%） of the sequence.The sequencing revealed an A-Trich region and bias in nucleotide base composition across taxa.Most of the species currently included in the section Batrachospermum with cox2-3 spacer sequence data were in a well supported clade distant to B.gelatinosum,the type of paraphyletic genus Batrachospermum.B.hongdongense,B.longipedicellatum and B.arcuatum previously placed in Batrachospermum section Batrachospermum,should be transferred into section Helminthoidea.B.curvatum and B.intortum belong to the newly established genus Kumanoa.