auctorum

Auctorum indicates that a name in botany and zoology is used in the sense of subsequent authors, and not in the sense as established by the original author. Its etymology derives from the Latin word for of authors (genitive plural), and is abbreviated auct. or auctt.

Some species names have been used twice for different species so the author of the name needs to be identified. For example "Leucospermum bolusii auct. Gandoger" for the species that was named as such by Gandoger. It is often used in conjunction with nec or non to indicate a misapplied name, e.g. "Leucospermum bolusii auct. non Gandoger" would mean the species not named by Gandoger.