Labels for herbarium vouchers

Labels for vascular plant vouchers vary among the various herbaria, but the essential components are predictable. At a minimum each label must include the scientific (latin) name for the plant, the location at which the plant was collected, the date of collection and the collectors name. Typically the label would also include a description of the habitat and associated species, an estimate of the plant's status at that site and a collector number. If the collector should mis-identify the plant, the voucher can thereafter be examined by a knowledgeable botanist and the correct identity is then written on the voucher sheet in the process known as annotation.
Typically, collectors press the plants in newspaper. Some local "shopper" newspapers, etc may be nearly the correct size for this purpose. Regular newspapers can be cut to about 18 x 12 inches. The plants must fit in this size because they must fit on a standard sized sheet of paper (16.5 x 11.5) in the collection . Specimens collected for vouchers must include plants or plant parts sufficient to reliably identify the voucher. For many plants that requires flowers and/or fruit, but for trees it is often possible to make a good voucher from mature leaves attached to a twig -- winter buds are also helpful and will be fully formed by mid to late July and extending throughout the next winter. September is a very good time to collect vouchers of many deciduous trees. As you gain experience in identifying the plants, you will learn what characters are necessary to identify them, and can therefore collect the vouchers accordingly.

Many collectors choose to assign a unique collector number to each specimen, usually beginning with 1, 2, 3 etc. and continuing for their entire career. The number can then be used in your field notes to keep track of the data pertaining to each voucher, and that same number can be written on the newspaper in which the plant is pressed to keep the specimen connected to the information. Taking and keeping good field notes is essential for those working in natural resources fields. It has been my experience that the information may also be important years later and for purposes not initially intended.

Most herbaria prefer to mount the vouchers themselves. We use a special kind of paper that is designed to last for a very long time and to resist changes in color and consistency of the paper. The glue is also chosen specifically for the making of herbarium vouchers and we print labels on archive-qualtity paper with permanent ink. Our preferred method is to receive each pressed and dried plant in the newspaper it was dried in, with the label or the label information on a separate sheet inside the newpaper. Fifteeen or twenty such sheets can be stacked, and then sandwiched between two pieces of heavy cardboard and snuggly wrapped and tied with string, or by taping the edges of the cardboard securely together to hold the plants securely and keep any parts from falling out. They can be mailed in this fashion, with several bundles together in a box if there are more plants.

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