Documenting New Zealand’s Ferns

Dr Patrick Brownsey and Dr Leon Perrie, Botany Curators at Te Papa, are involved in the ongoing task of documenting New Zealand’s fern flora. This involves fully describing and cataloguing all the species of ferns occurring in New Zealand, maintaining a comprehensive collection of specimens at Te Papa and providing a regularly updated list in the New Zealand Plant Names database on Landcare Research’s website.

Describing and cataloguing

To document New Zealand’s fern flora, researchers like Pat and Leon record the same information for each fern sample they collect. This information describes the fern and includes details such as:

• the accepted name of the fern (scientific, English, Māori)
• where it was collected
• what habitat it grows in
• the name of the person who collected the specimen and when it was collected.

Specimens of each fern are collected, pressed, mounted and labelled. More than one specimen of each species is collected and stored. This is because specimens will be taken from different areas or during different time periods. All specimens are then stored at Te Papa for future reference. Information about these ferns is published in research papers, in books or online, making this information accessible to anyone who is interested. In particular, a full description of each species can be built up from all the individual specimens, as well as information about whether it is endemic to New Zealand or occurs in other countries.

There are approximately 200 species of ferns that grow here naturally and another 30 to 40 species that have become naturalised. Patrick considers that they are quite a long way through documenting all of our country’s ferns. Surprisingly, however, they are still refining the classification of 1 to 2 new fern species each year. While they occasionally find a genuinely new species, they more often find information that can be used to update the taxonomy.

Molecular technology is one tool that is making this discovery easier. Researchers are now able to identify underlying genetic differences that can be used to support separating fern populations into different species.

Documenting a new fern species

When scientists come across a new species, the details they collect are published in a research paper. The information needs to be detailed and exact as they’re describing a species for the first time and making it known to the rest of the world. They are also the ones who give the new species a name. Leon and Pat were in this position when they recently described a new species of fork fern – Tmesipteris horomaka. Horomaka is the Māori name for Banks Peninsula where the fern is found.

As well as naming and describing the new fern species, the researcher needs to nominate a type specimen. Type specimens are a physical record of what the researcher has identified as a new species and are a reference point for ever more. (You can see the type specimen for Tmesipteris horomaka in Te Papa’s Collections Online). If there is ever any dispute about the species, scientists can refer back to the type specimen as the original example of that species.

The importance of documentation

Documentation of our fern flora is an important activity as it records what is here in New Zealand. It’s a way of cataloguing our natural resources and helping understand our biodiversity. Documenting provides information on rare and threatened species, geographic distribution of species and the relationship between species and may also help uncover species that have economic value.

The Te Papa fern collections, including specimens documented by Pat and Leon, are now available online at the New Zealand Virtual Herbarium. This online resource allows users access to the information from over 650,000 specimen records managed by herbaria around New Zealand. The careful process of documenting makes this possible.