Auxiinia

Auxiinia is a fictional genus of microalgae used in speculative biology and science fiction. The name blends the word auxin, a plant hormone, with the suffix -ia, signaling a microbial lineage tied to plant signaling molecules.

In most depictions, auxiinia is a eukaryotic alga that ranges from unicellular to filamentous forms. Individual cells measure roughly 6–12 micrometers in diameter and harbor chloroplasts with a distinctive suite of pigments that give a greenish-blue hue. Cell walls are described variably as organic mucilage or silica-containing in some worldbuilding variants. Reproduction is depicted as a combination of autospores and short-lived filaments.

Ecology and biology: Auxiinia is described as inhabiting nutrient-rich freshwater and brackish environments, often near aquatic plant roots or in waters influenced by plant exudates and synthetic auxin analogs. It is primarily photosynthetic, though some accounts attribute limited mixotrophy. A notable fictional trait is responsiveness to auxin-like signals, which in some stories modulates colony aggregation and morphogenesis, enabling rapid mats under certain chemical cues.

Legacy and usage: The concept has appeared in speculative biology circles and various science fiction anthologies since the 2010s. It is frequently cited in discussions of cross-kingdom signaling, ecological modeling, and biosafety considerations for synthetic biology, illustrating how plant-derived signals might shape microbial behavior.