Merismopedia

Taxonomy

Order Chroococcales
Family Microcystaceae
Genus Merismopedia

Morphology

Plate-like colonies, flat to slightly wavy, more or less square or rectangular (older colonies sometimes with irregular outline); flattened, plate-like colonies sometimes aggregate together into larger colonies; most colonies microscopic. Colonies may contain only a small number of cells, or more than 4,000 cells. Colonies are composed of a single layer of cells, with the cells arranged in perpendicular rows; cells may be densely packed or distant from one another. Colonial mucilage is colorless, fine, and typically has diffuse margins; cells of some species facultatively develop individual envelopes. Cells spherical to widely oval; if oval, then with the longer axis of the cell lying in the plane of the colony; hemispherical following cell division; (0.4)1.2-6.5(17)  μm in diameter. Cells pale to bright blue-green, rarely reddish. Cells of several planktic species possess one or a few aerotopes in their centers; otherwise without aerotopes.

Ecology

Species inhabit both freshwater and saline environments. In North American temperate regions, several species are common in the plankton and metaphyton of eutrophic to mesotrophic waters; other common species are metaphytic in mesotrophic lakes, ponds, and swamps.  

References

Johansen, J. R., & Komárek, J. (2015). Coccoid Cyanobacteria. In J. D. Wehr, R. G. Sheath, & J. P. Kociolek (Eds.), Freshwater Algae of North America: Ecology and Classification (2nd ed., pp. 91-95). Waltham, MA: Elsevier.

Komárek, J. & Anagnostidis, K. (2008). Cyanoprokaryota-1. Teil/Part 1: Chroococcales. In H. Ettl, G. Gärtner, H. Heynig, & D. Mollenhauer (Eds.), Süßwasserflora von Mitteleuropa (Vol. 19/1, pp. 169-179). Heidelberg, Germany: Spektrum.

Strunecký, O., Ivanova, A.P., & Mareš, J. (2023). An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis. Journal of Phycology, 59: 12-51. https://doi.org/10.1111/jpy.13304