Taxonomy
- Order
- Synechococcales
- Family
- Pseudanabaenaceae
- Genus
- Jaaginema
Examples of Jaaginema
400X total magnification; 10 μm scale bar.
400X total magnification; 10 μm scale bar.
400X total magnification; phase contrast.
Morphology
Trichomes solitary, in tangled clusters, or forming a thin, membrane-like thallus; never motile. Trichomes up to 3 μm wide; usually flexuous; typically unconstricted at crosswalls; sometimes slightly narrowed at the ends; not capitate (not abruptly wider and rounded at the end, as if with a cap on the end); without sheaths, or very rarely with a fine layer of mucilage around trichomes. Cells cylindrical; usually longer than wide (up to 10x longer), only rarely almost isodiametric. Apical cells typically rounded, occasionally conical; without a calyptra; very rarely with a slightly thickened outer cell wall. Cell content homogeneous and without aerotopes; sometimes with a solitary granule on either side of cell crosswalls (clearly visible in the third image to the right: seen in phase contrast, these granules look like white dots, in pairs along the length of the trichome).
Ecology
Mostly benthic; on sediments or aquatic plants; or in metaphyton. In North America, reported from lakes, rivers, and springs (thermal and mineral).
Not a very well-studied genus.
References
- Johansen, J. R., & Komárek, J. (2015). Filamentous Cyanobacteria. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Freshwater Algae of North America: Ecology and Classification (2nd ed., pp. 146-148). Waltham, MA: Elsevier.
- Komárek, J. & Anagnostidis, K. (2008). Cyanoprokaryota-2. Teil/Part 2: Oscillatoriales. In B. Büdel, G. Gärtner, L. Krienitz, & M. Schagerl (Eds.), Süßwasserflora von Mitteleuropa (Vol. 19/2, pp. 108-117). Heidelberg, Germany: Spektrum.