Collectors usually take several duplicate samples from the same specimen in the field, and each sample is given the same number and field note label. Once identified, these specimens are distributed to herbaria that have a regional or research interest in them. This exchange of material among herbaria enables each herbarium to acquire representative collections easily and cheaply and reduces the need for duplicated activity in a given area. Another great advantage of exchanging duplicate specimens is that it ensures that a particular collection is not lost to science should a major disaster befall an institution.
Temporary or extended loans of specimens between herbaria is another means of ensuring that researchers have adequate material on which to work. Loans are made to other recognised botanical institutions, rather than individual botanists, and the receiving institution takes full responsibility for the security and treatment of the specimens while they are in its care. Loans are generally made for an initial period of 12 months, with the possibility of extension. Conventions, agreed by herbarium curators, on the treatment of borrowed specimens cover such things as dissection of parts, handling of type specimens and re-identifications, and these are followed by the Gardens' Herbarium staff.
The Gardens will lend its specimens to recognised botanical institutions for taxonomic and systematic research. In return, it will borrow specimens from other institutions to facilitate its own research and will follow the agreed loan conventions of herbaria.