The virus particle is 80-120 nanometers in diameter and usually roughly spherical, although filamentous forms can occur.

These filamentous forms are more common in influenza C, which can form cordlike structures up to 500 micrometers long on the surfaces of infected cells.

In 1992 Fink and his students discovered that bakers' yeast could switch from a cellular form to a filamentous form.

They vary from single-celled flagellates to simple colonial and filamentous forms.

Long filamentous forms are often observed, but spores and capsules are absent.

The virion is pleomorphic; the envelope can occur in spherical and filamentous forms.

There are different mechanisms identified in some bacteria that are attributable to the development to filamentous forms.

As it has been observed in other organisms (such as fungi), filamentous forms are resistant to phagocytosis.

It is sold in filamentous, granular or powdered forms.

This organism exists in a filamentous form with one flagella per cell.