I only find Stokesia vernalis at long intervals of several years, mainly in the plankton. However, I have also observed a large population between floating plants in the Simmelried in May 2020.

The body shape of Stokesia vernalis is somewhat difficult to capture because the specimens swim in a tumbling motion. If the layer thickness is reduced, the specimens deform quickly.

In lateral view, the body is cap-shaped, with the tip of the cap forming the dorsal side. The ventral side, in the middle of which lies the mouth opening, is almost flat (s. fig. 1 a-b). Ventrally, the body is slightly heart-shaped, as it is slightly constricted by a suture running around almost the whole body. I myself could not recognize this heart shape in freely swimming specimens. In fixed, slightly squashed specimens, this constriction caused by the sutuere is no longer recognizable.

The oral apparatus is an elongated groove at the base of which runs a broad adoral membranelle. Two further, narrower membranelles are recognizable to the left of it (s. fig. 3 a-b). Finally, at the right margin of the mouth opening there is an undulating membrane, which I could not recognize exactly.

The contractile vacuole is located dorsally and has star-shaped collecting ducts (s. fig. 4 a-b). The collected water is released through several excretory pores. In my population mostly 4–5 excretory pores were visible (s. fig. 4 b).