Follow the same convention for related forms: a person from the Southern United States is a Southerner.
For example, Anglo-Saxon, Anglo-French and Anglo-Norman are all capitalized.
However, there is some variation concerning a small number of words of French origin.
When in doubt, discuss first on the talk page., i.e.
to try to impress upon the reader the importance or specialness of something in a particular context.
Reduce them to title case, sentence case, or normal case, as appropriate.
Most words with prefixes such as Anglo-, Franco-, etc., are capitalized.
For the style guideline on capitalization in article titles, see Wikipedia: Naming conventions (capitalization).
For the guideline on caption construction, see Wikipedia: Captions.
The main (but not mandatory) exceptions to the capitalization rule are the following.
Further information on article titles about organisms, including scientific names and common names and how and when to italicize their display: Wikipedia: Naming conventions (fauna) and Wikipedia: Naming conventions (flora) Scientific names including genus and species (sometimes also subspecies, or other infraspecific names) have an initial capital letter for the genus, but not for the [sub]species (and are always italicized): .
Doubts frequently arise when referring to regions, such as eastern Spain and Southern California.