Characium marinum is a species of green algae (Chlorophyta).
Characium marinum is a microscopic unicellular elongated oval algae growing attached epiphytically by a stalk various algae. The single chloroplast is parietal with a single pyrenoid.
Epiphytic on other marine algae. and eastern Canada
Recorded from Svalbard (Norway), Sweden, once in Ireland County Down, twice in Great Britain, under-recorded. and eastern Canada.
The taxonomic status of this alga is unclear. According to the marine biologist T. Levring, Characium marinum probably represents germlings of Cladophora, a genus of marine algae.