Polytomella

Polytomella is a genus of green algae in the family Dunaliellaceae. It is widespread in freshwater habitats worldwide. The algae is actually colourless. It has discarded the ability of photosynthesis, and lives by consuming compounds like acetate, butyrate, and alcohols. Thus, it's one of the rare examples of non-photosynthetic algae.

Polytomella consists of single, cells that lack cell walls. Cells are ellipsoid, pyriform, or globose, and slightly metabolic (flexible). Cells have four anterior flagella arising from a central papilla. The posterior of the cell is usually rounded, rarely pointed or with spine-like extensions. Although classified as an alga, chloroplasts and pyrenoids are absent and cells instead have vestigial leucoplasts. The cell accumulates starch in its cytoplasm. A single stigma and two to four apical contractile vacuoles are typically present. The single nucleus is located in the central or anterior half of the cell.