Desmid of the month
January 2005

Tetmemorus brebissonii

Just like in Euastrum oblongum (our desmid of the last month) cells of the genus Tetmemorus are marked by a deep, closed apical invagination. In contrast to the genus Euastrum, however, Tetmemorus cells are not flattened but cylindric or fusiform (so in transversal section almost circular, not elliptic-rhomboid as in Euastrum). World-wide, the genus Tetmemorus numbers only a few species. T. brebissonii differs from the other species in that the cell wall pores are arranged in longitudinal series. In the Netherlands, T. brebissonii in its occurrence is strictly confined to acidic, oligotrophic bog pools.