Two important missions of herbaria are: 1) to preserve the botanical
specimens entrusted to their keeping; and 2) to make the specimens
available for study by researchers. By and large, the primary uses of
herbarium specimens, such as examining morphology or recording
distributional data, are non-destructive.
Destructive uses of herbarium specimens (such as anatomical preparations
removal of pieces for DNA extraction) are generally strongly discouraged.
The University and Jepson Herbaria nevertheless acknowledge that there
instances in which the removal of a limited amount of material for
sampling does not seriously compromise the value of the specimen for
purposes; if done properly, the value of the specimen may even be
enhanced in that it has acquired additional status as a voucher. Our
policy on destructive sampling is therefore as follows:
Thank you for your cooperation with this policy. Please contact us
before proceeding with any destructive sampling that has not been
approved in writing.
- Herbarium specimens should not be the source of first choice if there
available sources for the desired material (e.g., field collections,
botanical gardens). Collaboration with local collectors, for example,
can be a mutually satisfactory arrangement.
- Destructive sampling will continue to be considered the exception to
the rule, not the normal procedure. As such, permission to remove
material must be requested in writing in advance and is subject to
specimen by specimen approval.
- Material may be removed only from specimens that have an abundance of
the kind of material being removed, such that the value of the specimen
for non-destructive research is retained.
- Destructive sampling of type specimens or similarly valuable
historical specimens is not permitted unless: a) the information to be
obtained is of critical significance; b) there is absolutely no other way
to obtain the desired material; c) sufficient material exists; and d) a
special exemption is granted.
- Specimens from which material has been removed are to be annotated to
indicate what was removed, when, where, and by whom. In light of the
status of the specimen as a voucher, a reference to where the results are
published and/or material is deposited is highly desirable. Example:
Leaf material removed for cp-DNA sequencing at UC by A.K. Johnson on 25
1996, in conjunction with doctoral studies on the phylogeny of Rosidae.
#1237; unused cp-DNA banked at UC; results published in Amer. J. Bot.