The accession number in modern specimens is often represented as a machine readable barcode.

The barcode accession number is used in the database to link all the information related to this specimen, such as the species name, the information on the herbarium label, specimen components and storage, etc.

The barcode facilitates rapid handling and retrival of information about specimens, in the preparation lists of specimens examined, loans and exchanges, for example.

The most common barcode format used in herbaria is '3 of 9'.