A branched filament, many of which together make up a fungal *mycelium
. Hyphal walls are usually made up of chitin laid down in microfibrils. The hyphae of most higher fungi are septate, i.e. divided by cross walls (septa) into many uni- or multinucleate segments. Those of lower fungi are commonly coenocytic. Hyphae may aggregate and anastomose to form a tissue-like mass of *plectenchyma
In certain fruiting bodies hyphae may be differentiated into thin-walled generative hyphae, thick-walled unbranched skeletal hyphae, and thick-walled branched binding hyphae. Flexuous describes the thin-walled branching hyphae found, for example, in pycnidia.