The phialide (/ˈfaɪəlaɪd/ FY-ə-lyde; Greek: phialis, diminutive of phiale, a broad, flat vessel) is a flask-shaped projection from the vesicle (dilated part of the top of conidiophore) of certain fungi. It projects from the mycelium without increasing in length unless a subsequent increase in the formation of conidia occurs.^[1]

It is the end cell of a phialosphore.

• Ascomycete