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Herbarium Voucher Specimens

A major role of the National Herbarium of Victoria is to collect and document the state flora, both native and naturalised species. Records of all species, including new and emerging naturalised species, are substantiated by herbarium voucher specimens.

A herbarium voucher specimen is a pressed and dried plant sample that can be stored for future reference.

Why are herbarium voucher specimens needed?

Voucher specimens provide a permanent record validating the occurrence of a plant species at a particular locality and time. Vouchers are also a verifiable and invaluable source of information such as distribution, ecological preferences, and associated species.

Plant classification is a dynamic, evolving science. Species concepts and species delimitations often change when new evidence becomes available. Consequently, the names applied to plants may change. Voucher specimens enable previous identifications to be verified or altered when the taxonomy changes, unlike the situation with identifications based on sight records, where it is often impossible to establish the current name in the absence of a specimen.

What makes a good voucher specimen?

The identification of plant specimens involves much time and effort. Well-collected and pressed specimens are essential and are more likely to result in an accurate identification.

There are two main elements to a herbarium voucher specimen:

The specimen

A quality herbarium specimen begins with the collection process itself:

Collect plants in flower/fruit. These are usually critical for identification.

Make specimens large enough to present a fair sample of the plant, its manner of growth, branching and so on.

With smaller plants such as grasses, rushes, sedges, irises and lilies collect whole plants (or a number of entire plants) including underground parts (i.e. bulbs, corms, rhizomes) still attached to aerial parts of plant.

Specimens should be pressed when fresh (i.e. in the field). This results in better herbarium specimens which are easier to identify.

When pressing a specimen, carefully spread out structures (i.e. leaves, flowers) so that diagnostic features are clearly evident. Make sure that the upper and the lower leaf surface are visible by turning over some leaves.

The label

The information recorded on the label is as important as the specimen. Even though a specimen may have been well collected and carefully prepared, it will be of negligible scientific value and in some cases impossible to confidently identify unless accompanied by basic field notes.

Essential label information

Collector(s) name

Date of collection

Precise locality: place/area name, property name (if private land), description of location in reference to roads, road junctions and distance from nearest place/town name.

Other useful label information
Note any information on characters and field observations not observable from pressed specimen:

Habit: growth form (e.g. tree; shrub; vine; herb) and height (e.g. dense shrub to 2 metres high; sprawling herb)

Bark type and extent (e.g. rough bark up to 2 metres on main trunk, smooth above). Especially important in Eucalyptus

Colour of fresh stems, leaves, flowers

Habitat: include a brief description of where the plant is growing (e.g. Themeda triandra grassland; grazed paddock; weedy roadside etc.) and a list of other plants growing in association if known.

Abundance: number of plants at site. Frequency in the area (rare, occasional, frequent/common or abundant)

Remember, it takes almost as much effort to make a poor specimen as it does to make an excellent specimen!