We use the Botanical names for ferns, because each species is carefully and accurately described when a new species is named. The Botanical system gives each species a double name - genus and species.
For example the brown fern, or rough tree fern, has the name: Dicksonia squarrosa. "Dicksonia" is the Genus it belongs to, and the Species is "squarrosa". No other species can have this name - it defines a unique organism that usually cannot breed with any other fern. Brown tree fern, rough tree fern and wheki are common names for the same plant. For botanical purposes, common names do not clearly define separate species and in many cases common names can actually refer to several quite different species. One name, one species, is the rule.
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When a new species is defined, a sample of the original discovered organism used to create that definition is held in a museum or University collection. For plants this is usually a pressed and dried sample showing all the parts that have been used to describe it. The descriptions use quite precise botanical terms and measurements.
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Click on this picture of Dicksonia squarrosa to view its detailed
description:
You can see how technical it is to define a species.
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Over the last 20 years, chromosome and DNA analysis have made distinguishing species much more precise, when coupled with the original careful descriptions and measurement. Those observations are still important, as they use visual characteristics that we can see, not things that require high powered microscopes and biochemical analysis.
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However, the newer methods have made it possible to recognize separate species within what were originally thought to be just one species. This has required botanists to create new names and change old names. Careful analysis of original records when botanists first described a new species, has even found some mistakes back then - such as recording the incorrect country where their samples were discovered. It wasn't easy collecting, preserving and recording samples on a rocking sailing ship with limited space!
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Ferns in particular have been subjected to many revisions of their botanical names. On this website, if a revision has been recent, we add the previous name in our description of the fern. Often folk know the old name and not the new one! It makes for some confusion at times, but this is the consequence of working towards a naming system that sticks to the rule of one name, one species, and also shows how closely the various species are related to each other. In the end, the latest botanical name is the best descriptor of any species using the most recent information that botanists have gathered.
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Where ferns have changed name recently, we have added the older name to the heading of that fern, so that the search box can find the old name as well as the new name and the common name.