Polygonia comma form of comma is frequently confused with the dark form of the question mark ("P. interrogationis"), but the two can readily be distinguished by the shape of the comma mark on the underside. The pale form is easily confused with the satyr comma ("P. satyrus"), which usually occurs north and west of the eastern comma's range. They can be distinguished by the upperside color, which is orange brown in the comma and tawny yellowish brown in "P. satyrus"; by the underside pattern, which tends to be mottled in the comma but appears to be more longitudinally streaked in "P. satyrus";
Comma signified by a dot at the bottom, middle, or top of the line. For a short passage (a "komma"), a "media distinctio" dot was placed mid-level ( · ). This is the origin of the concept of a comma, although the name came to be used for the mark itself instead of the clause it separated. The mark used today is descended from a diagonal slash, or "virgula suspensiva" ( / ), used from the 13th to 17th centuries to represent a pause. The modern comma was first used by Aldus Manutius. In general, the comma shows that the words