Dear Eldrin:

In my oppinion it could be Ulothrix, Ulotrichaceae, Ulotrichales, Chlorophyta.

Kind regards.

Eugenia

Eldrin:

Ulothrix is a good possibility.

Best

Syed

Thank you very much Eugenia and Syed...

I would also check Klebsormidium

Dear Eldrin!

I would like to recommend you to look at the genus Klebsormidium P.C.Silva, Mattox & W.H.Blackwell, 1972. For this genus are characteristic: uniseriate unbranched filaments without polar differentiation; one parietal plate-shaped chloroplast in a cell, with one pyrenoid, remarcably elongated and usually surrounded by distinct starch envelope, what I also see on your microscopic pictures. Klebsormidium occurs mostly in soil, subaerial habitats and on moist substrates but aquatic species are known; one species is marine. I have two candidates for your sample: Klebsormidium cf. flaccidum or Klebsormidium cf. nitens, please compare your detailed meassurements and please do not forget to check some literature:

Lokhorst G.M., 1996: Comparative taxonomic studies on the genus Klebsormidium (Charophyceae) in Europe. Cryprogamic Studies Vol. 5. Stuttgart, Jena and New York. Gustav Fischer Verlag, 132 pp.

https://www.researchgate.net/publication/233620179_Variation_and_taxonomic_significance_of_some_morphological_features_in_European_strains_of_Klebsormidium_Klebsormidiophyceae_Streptophyta

Best wishes

Bohuslav

Article Variation and taxonomic significance of some morphological f...

Article Biodiversity of Klebsormidium (Streptophyta) from alpine bio...

Thank you very much. The first time that I saw this in a microscope, I am thinking of this algae  as Klebsormidium sp.. I think I will check further the characteristics of my isolate and compare it both to Klebsormidium and Ulothrix. 

Dear Eldrin,

I agree with the suggestions of Dr. Bohuslav. The vegetative(as we could observe from the picture)  morpholgy resembles that of  K. flaccidum or K. nitens. Cells are  1.5-2.5 times  longer than broad with a plate-like or ribbon-like single chloroplast with a pyrenoid covering 50-80% of the cell wall( which is very thin)

H-shaped pieces are not prominent in K. flaccidum and  K. nitens which differ from each other only in their filament- width and the aperture of the zoosporangium  to release zoospores.

Good luck!

Chloroplasts here are similar of those observed in Klebsormidium and very different from those of Ulothrix.