Lowland mid-sized stream 300m altitude.
FIXED WITH ETANOL
It forms macroscopic colonies consisting of cell groups enclosed within mother cell wall in a mucilaginous envelope.
Cells with a single pyrenoid and parietal chloroplast
thanks in advance
Dear Maria,
Please check Hormotilopsis gelatinosa (= Gloeophyllum fimbriatum). The drawings of the species from natural environment are available in Korschikov 1953. http://www.algaebase.org/search/species/detail/?species_id=K7cb8b638cd797736
Best regards
Roman
Your description did not state if your sample was from an epilithic, epipelic or planktonic collection. Nevertheless, this alga appears to have its cells embedded within a colorless mucilaginous matrix with the morphological features that are similar to Cecidochloris Skuja (1948) or Chlorophysema. J.W.G Lund (1956) description of these taxa may be of assistance in further defining the morphological features that may distinguish one from the other. According to Bourrelly (1966), the mucilaginous matrix, he refers to as a lorica, has a brownish color and a short stalk in genus in the Chlorophysema while Cecidochloris is without this basal stalk. Yet, Chlorophysema is regarded in recent revisions as a synonym of Cecidochloris adnata.
http://www.algaebase.org/search/genus/detail/?genus_id=E596d682bdb73c799&-session=abv4:AC1F10080a2f62295ARj5DE50DCA
Bourrelly, Pierre. 1966. Les Algues d'eau douce. 1, Les Algues vertes, Paris.
On the other hand, I would not dismiss the possibility of it being a species of Gloeocystis –also with similar characteristics with cells containing a pyrenoid. A closer examination of the cell is warranted under higher magnification for those cellular features that distinguish these three taxa from each other. Good luck!
Fritsch classified these three taxa within the Volvocales, suborder Tetrasporineae, Family Palmellacae.
Fritsch., F.E. 1965. The Structure and Reproduction of the Algae. Vol. 1. Cambridge
Thanks George for your answer.
The samples WAS NOT A PLANKTONIC one, i am not sure if it was epilithic o epipelic.
Gloeocystis is more a planctonic one, isnt it? But de cells are more o less similar to this taxon.
Actually Gloeocystis vesiculosa - a member of the Tetrasporales has been reported in streams as an attached alga. Based on your photographs, the embedded cells within its muscilagenous matrix appear to form along a flattened plane - similar to what one would expect if this amorphous mass of cells was firmly anchored to a rock or other hard substrate within the stream where it was found. The specimen you have may have been free-floating after it was sluffed off its substrate during the time of collection it could have been a scrapping from a rock or other hard surface. That's my guess. Yet, I would not dismiss the possiblity for the other taxa that I had described following a detailed examination at high magnification.
Best wishes, George
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