Diagnostic features
Unicellular desmid with two semicells divided by a deep midline constriction or isthmus, each with short or long arm-like processes, which may be patterned with an array of ridges or spines, and are radially arranged around the cell (cf. Micrasterias, in which "arms" always lie in one plane). Each semicell contains a single chloroplast. Nucleus often visible in the cell centre between the chloroplasts.
![[Staurastrum], Lake Johnson, X640. Photo: Otago Regional Council & Manaaki Whenua Image](/assets/Tools-And-Resources/Identification/algae/staurastrum640__ScaleWidthWzEwMjRd.jpg)
![[Staurastrum], Lake Rotoiti, X640. Photo: Otago Regional Council & Manaaki Whenua Image](/assets/Tools-And-Resources/Identification/algae/staurastrum640b__ScaleWidthWzEwMjRd.jpg)