Xanthidium groenlandicum BOLD fa. depauperata LARSEN The cells are little wider than long and almost square in shape. The central cut is deep and extends strongly outwards. The cell halves are stretched octagonally with broadly rounded ends. At the cell sides there are two broadly blunted, conical extensions and a hardly visible projection on both sides of the cell vertices. In the center of the cell halves is a flat swelling, which is covered with small warts or dimples. From this alga only three illustrations exist so far: BOLDT (1888), LARSEN (1907) und GRÃNBLAD (1952). Length 60 - 63 µm, width 65 - 68 µm. Occurrence: Known only from Greenland so far.
