Actinotaenium rufescens. Notice the coarsely punctate cell wall and the longitudinal chloroplast ridges.

Cell dimensions (L x B): 68 x 26 µm



Desmid of the month
April 2011

Actinotaenium rufescens

As its name indicates, Actinotaenium rufescens is characterized by a brownish colour of the cell wall (although not always expressed). A second remarkable feature is found in the coarse punctation of the wall. Like in other Actinotaenium species with a comparable cell size, the axial chloroplasts are provided with a number of distinct longitudinal ridges. Actinotaenium rufescens is a rare arctic-alpine species, to be encountered in acidic oligotrophic bog pools. From the Netherlands but a few records are known, the latest dating from the nineteen seventies.

Actinotaenium rufescens
Image © Koos Meesters

Another cell of A. rufescens with a strikingly brownish wall.

Actinotaenium rufescens, SEM pictureImage Hanny Kooijman – van Blokland © IBED

SEM picture of Actinotaenium rufescens

Actinotaenium rufescens, SEM picture, detailImage Hanny Kooijman – van Blokland © IBED

Detail of the wall at the isthmus showing that most (all?)
of the cell wall pits are linked up with a pore.