Appresorium

Appresoria, the plural of appresorium, are the tips of infectious hyphae, often from a germinating spore, that make contact with their host cell wall and that flatten out into disc, fan or lobed shapes tightly affixed or appressed on the host cell wall. The appresorium serves to bind the fungus and host together, and often precedes formation of a penetration peg that grows out from the base of the appresorium directly into the cell of the host.