Green algae - Conjugate algae - Staurastrum
Staurastrum chaetoceros
Staurastrum senarium has short spikes in the corners. The length can be 116-185 my. The cell wall is smooth and so the out-growth. Staurodesmus exemplify different patters of symmetry dependant of the way the cell are viewed.
Staurstrum arctiscon
The image shows the new cells growing from each semi-cell.
The image is Staurastrum seen from the end.