Stromia

Stromia is a fictional genus of planktonic microorganisms used in science fiction and worldbuilding. In common depictions, Stromia comprises single-celled or colonial marine protists a few micrometers in diameter, with a gelatinous envelope and a reticulate cytoplasm. They are portrayed as motile through flagella or pseudopodia and capable of simple colony formation on submerged surfaces.

Taxonomy and naming: Since Stromia originates in fiction, it has no standing in real-world taxonomy. Authors apply the name as a genus label within various higher groups, and described traits differ between works. Etymology is typically linked to roots such as Greek stroma or related terms meaning layer or cushion, plus the usual genus suffix -ia.

Ecology: In fictional ecosystems, Stromia often acts as a primary or secondary producer, sometimes forming mutualisms with photosynthetic partners or decomposing dissolved organic matter. Some narratives depict it as an ancient lineage relevant to discussions of early cellular evolution or the origins of multicellularity.

In fiction and worldbuilding: Stromia appears in glossaries and field guides of coastal or ocean worlds, serving as a flexible stand-in for microbial ecology. Descriptions vary to fit the needs of a particular story or speculative model, but the genus is commonly used to illustrate ideas about microbial life, ecological interactions, and evolutionary concepts in a concise, accessible way.