Trichosarcina is a genus of green algae in the order Ulotrichales. Filoprotococcus was once regarded as a synonym. However, Filoprotococcus is now considered valid in its own right. Trichosarcina is considered to be of uncertain validity.
, AlgaeBase accepted only one species, Trichosarcina polymorpha. Its life cycle includes a , Hormidium-like phase; a pluriseriate stage, and, finally, a chain of sarcinoid packets which may dissociate. The cells are , with a parietal chloroplast and single pyrenoid. Quadriflagellate zoospores are produced by cells of the pluriseriate and sarcinoid stages.