Hypha

Definition

A long, branching, filamentous structure that constitutes the basic vegetative unit of fungi, oomycetes (water molds), and some actinobacteria. Hyphae grow apically, may be septate (divided by cross-walls) or coenocytic (multinucleate and continuous), and collectively form a mycelium—the diffuse, absorptive body that penetrates substrate and mediates nutrient acquisition, reproduction, and ecological interaction.

Etymology

From Greek hyphē, 'web' or 'woven fabric', referring to the thread-like, interwoven growth habit.

Example

Entomopathogenic fungi such as Beauveria bassiana produce specialized hyphal bodies that breach insect cuticle, proliferate through the hemocoel as yeast-like blastospores, then re-emerge as external hyphae that produce conidia for horizontal transmission to new hosts.

Related Terms

• mycelium
• septum
• coenocyte
• rhizomorph
• haustorium
• entomopathogen
• Fungivory
• gut mycobiome
• ambrosia beetle
• leaf-cutter ant

Usage Notes

In entomological contexts, hyphal morphology often distinguishes fungal infection stages: invasive hyphae damage host tissues, while external hyphae serve dispersal. The term excludes superficially similar bacterial filaments (trichomes) and cyanobacterial strands. Oomycete hyphae are convergent structures, not homologous with true fungal hyphae, a distinction with practical implications for disease management in agricultural entomology.