Tychonema

Taxonomy

Order Oscillatoriales
Family Microcoleaceae
Genus Tychonema

Morphology

Filaments solitary or forming fine, disintegrating mats. Trichomes cylindrical and isopolar; not attenuated at ends; mostly straight, or occasionally slightly irregularly coiled or somewhat curved; unbranched; usually not constricted at crosswalls; up to 16 μm wide. Nonmotile, or with slight trembling, gliding, or rotating motility. Sheaths absent, or produced facultatively; facultative sheaths fine and mucilaginous. Cells cylindrical and roughly isodiametric, or shorter than wide or up to two times longer than wide. Apical cells rounded; sometimes with a thickened cell wall or narrow calyptra. Keritomized chromatoplasma (appearing vacuolated; with nearly colorless areas visible within the cell). Cells often containing prominent granules; gas vesicles never present. Coloration is pale grayish-pink, purplish, reddish, or olive green, or pale blue-green. 

Ecology

Solitary filaments or mats may be planktonic, tychoplanktonic, or benthic. May be restricted to colder northern temperate areas.

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. 162-168). Waltham, MA: Elsevier.

M.D. Guiry in Guiry, M.D. & Guiry, G.M. (03 March 2015). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 10 February 2023.

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