Background and aim – The non-marine diatom communities in the Antarctic Region are characterized by a typical species composition, in close relationship with their environment. Despite the growing interest, the diatom flora of James Ross Island is only poorly known. The present paper discusses the diversity of limnoterrestrial diatoms on this island: seepages and streams. Methods – The diatom flora of 53 samples taken on the eastern side of the Ulu peninsula on James Ross Island has been studied using light and scanning electron microscopy. Key results – A total of 69 diatom taxa belonging to 26 genera have been observed. The genera Luticola, Diadesmis, Muelleria and Pinnularia dominated the species composition. The flora shows an interesting mixture of cosmopolitan and Antarctic species containing several species reaching on James Ross Island their most northern distribution in the Antarctic Region. The taxonomical position of one widespread Antarctic species, Psammothidium papilio (D.E.Kellogg, Stuiver, T.B.Kellogg & Denton) Kopalová & Van de Vijver comb. nov., is corrected. Conclusions – The limnoterrestrial diatom flora of James Ross Island has a rather low number of species, of which a large proportion shows a restricted Antarctic distribution.

ANTARCTIC PENINSULA; BACILLARIOPHYCEAE; BIOGEOGRAPHY; DIATOMS; JAMES ROSS ISLAND; SEEPAGES; STREAMS