HERBARIUM

The Herbarium explained

The Herbarium is a collection of preserved plants that are stored, catalogued, and arranged systematically for study. When specimens are collected in the field, the Herbarium and associated information in the library is used to identify these specimens, to determine how one species differs from another, or whether a specimen represents a species new to science.

Herbarium specimens act as a source of information, to determine: what the plants look like; where they are found; what environmental niche they occupy; which species are threatened by extinction; what morphological and chemical variation occurs; and, when they flower or produce seed. Specimens can be used to provide samples of DNA to study relationships and evolutionary processes. They also act as vouchers to validate scientific observations. The Herbarium is therefore of immense practical use and of fundamental importance to science.

Individual plants (or parts of plants) are preserved, stored and cared for over time so that current and future generations can identify plants, study biodiversity and use the collection in support of conservation, ecology and sustainable development. 

The Herbarium holds specimens of vascular plants which include ferns, lycopods, gymnosperms (including conifers and cycads) and flowering plants. Non-vascular plant specimens such as bryophytes (mosses and liverworts) were transferred to the Natural History Museum following an agreement in 1961. 

Herbarium specimens

A specimen may consist of a whole plant (in the case of small herbs) or parts of a plant (in the case of large trees or bushes). Specimens typically include samples of the leaves, stem, and bark, and ideally should include flowers and/or fruits, since these are of most use later when identifying plants or using the specimens to study relationships between plants. Additional, ancillary collections will often be made at the same time.

Exactly what is collected will depend on the plant, but it might include wood samples, dried fruits, flowers preserved in spirit, photographs or DNA samples. Modern collections will typically include latitude and longitude recorded in the field using GPS. Exact localities can be calculated for older specimens using the information recorded on the specimen label and sources such as gazetteers.

Specimens are organised systematically, by family, genus and species, which means that related species are found close to one another thus facilitating their comparison. Herbaria that organise their specimens in this way serve as a working hypothesis for the classification of all plants.