Cells lack organelles

Cells small, irregularly dispersed in homogenous jelly

Chroococcus (Chroococcaceae)

Cells usually not spherical, occurring in pairs or tetrads surrounded by jelly.

Gloeocapsa (Microcystaceae)

Colonies of cells with concentric rings of jelly. Jelly is often red in colour.

Merismopedia (Merismopediaceae)

Cells closely appressed, arranged in an extensive, orderly, flat sheet.

Placoma (Hydrococcaceae)

Colonies are gelatinous and strongly lobed, containing numerous cells, which are located near the colony surface.

Xenococcus (Xenococcaceae)

Colonies attached to substrate in single layer of cells of widely varying size.