A hypha (plural hyphae) is a long, branching filamentous cell of a fungus. Hyphae grow at their tips. During tip growth, cell walls are extended by the external assembly and polymerization of cell wall components, and the internal production of new cell membrane.
New hyphae are typically formed by emergence of new tips along existing hyphae by a process called branching, or occasionally growing hyphal tips bifurcate (fork) giving rise to two parallel-growing hyphae. The combination of apical growth and branching/forking leads to the development of a mycelium, an interconnected network of hyphae.
