Cylindrocapsa

Cylindrocapsa is a genus of green algae, specifically of the Chlorophyceae. It is commonly found in freshwater habitats.

Virus-like particles have been found in a strain of one species, Cylindrocapsa geminella.

Description
Cylindrocapsa consists of unbranched filaments, often attached to substrates or free-floating in water. Cells are initially uniseriate (that is, in one line), but may later become multi-seriate or irregularly arranged. Individual cells are ovoid to oblong to spherical, and are each surrounded by several concentric layers of a mucilaginous sheath. Cells contain a single chloroplast filling the cell, with a single pyrenoid. The chloroplast may be axial (in the middle of the cell) or parietal (lining the wall of the cell).

Taxonomy
The placement of Cylindrocapsa is unclear. Species differ significantly from each other, both in terms of morphology and ultrastructure. It is therefore suspected to be polyphyletic.