Template:Is reg()/doc

Usage
Input: Taxon name

Output:
 * If Taxon is a regnum (or equivalent higher category),
 * Else: Null.

Intended use: Call repeatedly for each taxon in a taxobox (using Get regnum). Because a null string is returned for all non-regna, all that remains will be the regnum. Pass this output to Taxobox colour to generate colours for a taxobox.