Conidia on conidiophores. A hypha (plural hyphae, from Greek ὑφή, huphḗ, “web”) is a long, branching filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.Yeasts are unicellular fungi that do not grow as hyphae. Aseptate or coenocytic (without septa). 2  Non-septate hyphae are associated with Mucor, some zygomycetes, and other fungi.  3 Pseudohyphae are distinguished from true hyphae by their method of growth, relative frailty and lack of cytoplasmic connection between the cells.