| Division | Chlorophyta |
| Class | Chlorophyceae |
| Order | Sphaeropleales |
| Family | Hydrodictyaceae |
| Basionym | Polyedrium gracile Reinsch |
| Synonym | Isthmochloron gracile (Reinsch) Skuja; Pseudostaurastrum gracile (Reinsch) Bourrelly. |
Cells rectangular, flat with narrow processes produced at the corners of the cells. Each process usually branch twice and end with short spines. Primary branches usually right angles with one another and parallel to one side of the cell. Cells with processes 35-70 μm in diameter, without processes, 10-24 μm in diameter.
Ecology
Freshwater alga prefers oligo-mesotrophic water bodies.