Voucher Specimen

A collected and permanently preserved (usually dried) plant specimen that is proof a particular taxon has been correctly identified in a scientific publication.  When known, a museum or herbarium known to house a voucher specimen documenting the occurrence of a particular taxon for a specific state or equivalent area is cited.  The voucher specimen is presented as scientific evidence that the taxon is currently or was historically present within that state or province.  Voucher specimens are normally held by scientific institutions and are available for examination by researchers.  The voucher specimen allows botanical researchers to verify that a distribution record is based on a correct identification of the taxon in question.  BONAP is working together with curators and other individuals in every U.S. state and Canadian province to complete the vouchering process (see Specimen Voucher Documentation).  To the degree possible, we are working first at the state level rather than the regional or national level to complete the vouchering process.  By doing so, we will permit the individual states and provinces to record vouchers found within their internal institutions, rather than to rely upon national collections that are rarely visited by individual state botanists.  Only when in-state vouchers do not exist, will BONAP record such vouchers from regional or national collections.  This approach should provide incentive for curators of state repositories (herbaria and museums) to secure voucher collections of taxa that are currently not housed within their states.  Currently, through the effort of our collaborators, the vouchering system is completed for approximately one-half of all state-level distribution records for North America north of Mexico.  We anticipate that the remaining half will be completed within the next few years.