Mesostigmatophyceae
There are many ways to place the Mesostigmatophyceae into a category. One popular way is to have it only one genus, which is Mesostigma. A different way to do it is two have two clades; Chlorokybus and Spirotaenia. It is also common to put Chlorokybus in a different class as Chlorokybophyceae. Below is a common way to sort the categories.