A herbarium is a collection of preserved plant specimens, usually pressed flat, dried and mounted on archival sheets, with a label recording where, when and by whom each plant was collected. They are among the most important resources in botany, and the study of the Melastomataceae relies on them heavily.
What is on a specimen sheet?
A typical herbarium specimen includes:
- A pressed piece of the plant, with leaves and, ideally, flowers or fruit.
- A label with the collector's name and number, the date and the locality.
- Notes on habitat, flower colour, height and anything lost in drying.
- The scientific name, and annotations by specialists who later examined it.
Why herbaria matter for melastomes
Identification. Melastomes can be hard to tell apart. Specialists compare new specimens with authenticated ones to work out which species they represent.
Description of new species. A new species must be described in a published paper that designates a type specimen, which is deposited in a herbarium. See how new species get described.
Mapping distributions. Specimens document where a species has been found over time. This helps researchers define ranges and spot decline (conservation of melastomes).
Resolving names. Type specimens act as the reference point for a name, which is crucial when sorting out synonyms and accepted names.
Historical record. Some specimens are well over a century old and preserve evidence of species and places that have since changed.
Types of specimens
- Holotype: the single specimen designated by the author as the reference for a new name.
- Isotype: a duplicate of the holotype collected at the same time.
- Lectotype: a specimen chosen later when no holotype was designated.
- Voucher: a specimen kept as evidence for a study, for example a DNA or ecology project.
How big is the world's herbarium resource?
Herbaria around the world hold hundreds of millions of specimens. Major collections exist at botanical gardens, universities and natural history museums. Many university herbaria, including those with melastome specialists, support ongoing research on the family.
Digitisation
Many herbaria are scanning their specimens and putting images and data online. Platforms such as GBIF and regional portals allow anyone to search specimens by name, place or collector. For a melastome enthusiast, this means you can often view images of type specimens without leaving home.
How to use herbarium data
- Search a name on a portal such as GBIF.
- Filter for preserved specimens with images.
- Look at the label to see where and when the plant was collected.
- Compare leaves and flowers with your own photographs (identifying a melastome).
Citizen science and collecting
Anyone can contribute, but collecting wild plants may require permits, and protected species must never be collected. If you want to document plants, photographs and careful notes are often the best approach.
Takeaways
- Herbarium specimens are the evidence base for plant taxonomy.
- Type specimens anchor scientific names.
- Digitisation has made collections more accessible.
- Melastome research, from new species to conservation, depends on them.