Hi People,
I've just registered after a couple of years lurking in the background and admiring all your work. Some really wonderful photos, some technically impressive, some beautiful, all interesting - thank you. I hope to post a few of my own photos soon.
Daniel, I don't think that it is Pleurotaenium ehrenbergii but rather P. trabecula. There are a few clues. P. ehrenbergii usually has more undulations in the middle and then straighter sides. The key is the cell end, P.ehrenbergii has flattish cell ends (yours are rather rounded) and the definitive feature (which appears to be absent in your specimen) is that it has a number of tubercles / bumps on the cell wall at the ends.
A great web resource for desmids are the plates of West and Wests 5 volume book on the desmids. The book is about 100 years old, so a lot of the names have changed, but the pictures are great. The plates (which are searchable ) are hosted at the royal botanic gardens edinburgh website ( diatom images are also available there).
http://rbg-web2.rbge.org.uk/DIADIST/ind ... o.htm&main
Keep looking down,
all the best
Brian