Desmid of the month
May 2006
Micrasterias jenneri
Just like in Micrasterias truncata (desmid of May, 2004) the lateral semicell lobes in M. jenneri are only twice divided (to lobules of the second order) and the apical lobe is very short and broad. Most relevant discriminating characteristic of Micrasterias jenneri (as compared to M. truncata) is the shallow but well-marked, median incision in the apical lobe. In western Europe, the ecological demands of Micrasterias jenneri are comparable with those of Xanthidium armatum and Cosmarium ralfsii, i.e., acidic, boggy pools with a slight input of minerals from the (often loamy) subsoil. Nowadays, Micrasterias jenneri in the Netherlands is a rare species, particularly known from a few moorland pools in the province of Drenthe.
Image
© Wim van Egmond
Micrasterias jenneri. Notice the broadly rounded lobules and the shallow, median, apical incision characteristic of this species.
Cell dimensions (L x B): ca 160 x 120 µm
