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";
Punctuation of English in text messaging and other short-form online communication, where more formal or "closed" punctuation can be misinterpreted as aloofness or even hostility. Open punctuation eliminates the need for a period at the end of a stand-alone statement, in an abbreviation or acronym (including personal initials and post-nominal letters, and time-of-day abbreviations), as well as in components of postal addresses. This style also eschews optional commas in sentences, including the serial comma. Open punctuation also frequently drops apostrophes. Open punctuation is used primarily in certain forms of business writing, such as letterhead and envelope addressing, some business letters, and résumés and