Tetraselmis suecica

Tetraselmis suecica is a marine green alga.

Tetraselmis suecica consists of unicellular, motile cells with four equal flagella about as long as the length of the cell, arising from a single apical furrow. The cell wall is smooth and rigid. Cells are 9–11 μm long, 7-8 μm wide, and 4.5–6 μm thick. Cells are compressed, ovoid in dorsal view and ellipsoid in lateral view. Cells contain a single, campanulate chloroplast which is dissected into two or four lobes. The chloroplast has a conspicuous basal pyrenoid surrounded by a starch sheath. The stigma is small, reddish and situated at the base of the cell near the pyrenoid. Cells contain a single central nucleus, several pale spherical bodies in the chloroplast, and several dense bodies in the apical lobes.

Reproduction occurs by division of the protoplast within the cell wall, resulting in daughter cells which have flagella prior to release. Cysts are sometimes formed within culture.