oneseptate

Oneseptate is a descriptive term used in mycology to refer to hyphae that contain exactly one septum, effectively dividing the filament into two cellular compartments. In practice, oneseptate is typically considered synonymous with monoseptate or one-septate hyphae, though oneseptate is a less common or less standardized spelling. More widely used terminology tends to favor monoseptate or one-septate hyphae to describe this condition.

Septa are cross-walls within fungal hyphae that can host pores, allowing limited cytoplasmic exchange and transport of nuclei, organelles, and nutrients between adjacent compartments. The presence of a single septum influences hyphal physiology, including cytoplasmic flow, growth dynamics, and how hyphae respond to environmental conditions. This contrasts with aseptate (no septa) hyphae and with hyphae that possess multiple septa (polyseptate or highly septate).

Occurrence and notes: Monoseptate or oneseptate hyphae are described across various fungal lineages and can appear in specific developmental stages or morphological forms. Because oneseptate is not as standardized a term as monoseptate, some taxonomic descriptions may prefer the latter, while older literature or certain editors may use oneseptate. When encountered, it typically signals that the filament has a single dividing wall rather than multiple cross-walls.

See also: aseptate, septate, monoseptate, hypha, fungal morphology.