Desmid of the month
July 2011
Closterium angustatum
Cells of Closterium angustatum are only slightly curved, in the midregion with parallel margins, toward the ends only slightly narrowed. Apices are truncately rounded and usually somewhat swollen (capitate). The cell wall is marked by one or more girdle bands and distinct, longitudinal striae that are far apart and a bit rib-like (costate). Cl. angustatum is characteristic of acidic, oligo-mesotrophic bogs and moorland pools. In the Netherlands, nowadays it is very rare.
Image © Koos Meesters
Detail of the midregion showing longitudinal chloroplast ridges that somewhat mask the cell wall costae.
Image © Koos Meesters
Detail of the cell end of a living cell showing a capitate apex and a terminal vacuole holding a big crystal.
Closterium angustatum. Notice that the cell is only slightly curved, with an extensive girdle band in the midregion and capitate ends.
Cell dimensions (L x B): 480 x 26 µm
Image © Koos Meesters
Detail of the midregion of a dead, empty cell clearly showing the cell wall costae.