International Code Of Nomenclature For Algae Fungi And Plants

Why does naming seaweed, mushrooms, and roses feel like it requires a UN summit?

Picture this: You’re at a botanical garden, pointing at a weird seaweed clump and saying “That’s Ulva lactuca*,” while your friend confidently calls it Enteromorpha*. Meanwhile, three feet away, someone’s Instagram caption says “so cute little algae!”

Who’s right?

The answer lies in one of biology’s quietest but most essential rulebooks—the International Code of Nomenclature for algae, fungi, and plants. In practice, it won’t get you a TikTok following. But imagine trying to write a paper on photosynthesis when half the researchers call the same molecule “chlorophyll A” and the other half “Chl-a. It’s not flashy. But without it, science would descend into beautiful chaos. ” That’s what we’re preventing here.

What Is the International Code of Nomenclature for Algae, Fungi, and Plants?

The International Code of Nomenclature for algae, fungi, and plants—often called the ICNafp or simply the Shenzhen Code after the 2018 meeting where it was last updated—is a set of rules governing how we name new species in these three kingdoms. Think of it as the grammar book for scientific Latin names. Most people skip this — try not to.

It’s not one monolithic document. It’s actually four separate codes that were unified under the International Code, each originally governing algae, bacteria, viruses, or other groups. But since 2011, these codes have operated under a single framework, ensuring that whether you’re describing a new orchid species or a bizarre deep-sea fungus, you’re following the same basic naming logic.

The code isn’t about creating names—it’s about establishing priorities. When multiple people describe the same organism, the code decides which name “wins.” It’s brutal, but fair.

Why Should You Care About These Latin Names?

Here’s where it gets practical. Let’s say you’re a researcher studying a particular type of coral. Six months later, another lab publishes work on what they think is the same species but calls it Stylophora pistillata*. You publish your findings using the name Acropora palmata*. Your results look contradictory. They don’t—because you’re studying different organisms.

Or worse: both names were valid at some point, but the code later determined one was a synonym. Without understanding the naming history, you’d think science couldn’t make up its mind.

The code also prevents duplication. On the flip side, today, you need a published description, a type specimen deposited in a recognized herbarium, and you have to follow specific formatting rules. Before 1753, anyone could slap a Latin name on a plant. No more reinventing Rosa gallica* because someone forgot it already existed.

How the Naming Game Actually Works

The Basics: Binomial Nomenclature

Every species gets two names: genus and specific epithet. Homo sapiens*. Pinus sylvestris*. Saccharomyces cerevisiae*. Which means the genus name is always capitalized, the epithet lowercase, and both italicized. Simple enough, right?

But here’s where it gets nuanced. That said, the specific epithet isn’t unique across all of biology. Sapiens* appears in multiple genera—we’ve got Pan sapiens* (though that’s deprecated) and Homo sapiens*. Context matters enormously.

Priority: The Golden Rule

When someone describes a new species, they get first dibs on the name—assuming they follow the rules. This is called priority. Worth adding: if Quercus robur* was published in 1753 and Quercus europaeus* in 1760 describing the same oak, the older name wins. Unless.

Exceptions That Break the Rules

The code has built-in rebellion mechanisms. Names can be rejected if they’re “unconsciously” applied to widely used names. As an example, if Aus bus* has been the common name for decades but someone publishes Aus bus* in 2020 describing the same thing, the community can vote to keep the old name.

Conserved names work similarly. And ginkgo biloba* could theoretically be renamed based on priority, but it’s preserved because everyone knows it as Ginkgo. The code protects common sense.

Typification: Pinning Down Identity

Every name needs a type specimen—a physical example stored in a recognized collection. Think about it: this isn’t just paperwork. It’s the reference point that anchors the name to actual biology. If someone later argues that Taraxacum officinale* (common dandelion) actually refers to a different species, they have to compare against the type specimen, not just their memory.

Common Mistakes People Make

Confusing Synonyms with Different Species

It's the most frequent error I see in literature reviews. Some names are synonyms—different authors describing the same thing at different times. Here's the thing — often, they’re not. On top of that, researchers will list five papers on “species X” and assume they’re all studying the same organism. Others are homonyms—same name, different things.

The code provides tools to sort this out, but you have to look it up. Databases like Index Fungorum, IPNI, and AlgaeBase maintain current accepted names and their synonyms.

Treating the Code Like a Suggestion

I’ve read papers where authors deliberately ignore typification rules because “it’s too hard to find the type specimen.” They’re not wrong about the difficulty—but they are wrong about the consequences. If your name isn’t validly published, other researchers can’t build on it reliably.

Assuming All Organisms Need Names

Here’s what most people miss: the code only applies to new descriptions of organisms that have already been named. You don’t need to follow these rules to describe a new species of bacteria in your lab notebook. But if you want that description to be recognized internationally, yes, you need to play by the rules.

Practical Tips for Working With the Code

Start With the Right Database

Don’t trust Google Scholar for nomenclatural history. Use specialized databases. Worth adding: for plants, the International Plant Names Index (IPNI) is gold standard. For fungi, Index Fungorum. For algae, AlgaeBase. These aren’t just repositories—they’re nomenclatural authorities that track synonymy, type specimens, and publication details.

Learn to Read a Herbarium Label

Type specimens have specific formats. They include collection data, herbarium acronyms (like NY for New York Botanical Garden), and accession numbers. If you can’t locate a type specimen, your name might be invalid.

Understand What “Valid Publication” Means

A name isn’t valid just because you wrote it down. So it needs to be published in a work that meets specific criteria: permanent availability, clear description or diagnosis, proper designation of a type. Many online-only publications fail this test.

Keep Track of Novel vs. Valid Names

A “novel name” is one someone has published. A “valid name” is one that meets all the code requirements. You can have a valid name that’s not novel (a synonym) or a novel name that’s not valid (published without proper description).

Continue exploring with our guides on angle 1 and angle 2 are adjacent angles and what are the properties of carbon.

Frequently Asked Questions

Do these rules apply to DNA sequences too?

Not directly. The code governs names of organisms, not genetic sequences. That said, when you publish a new DNA barcode, you should link it to a properly named specimen. Otherwise, you’re creating a parallel naming system.

What about hybrids?

Hybrids get their own naming rules under the code. They use a multiplication sign (×) and can involve different genera or species. Even so, × Fatshedera lizei combines Fatsia* and Hedera*. The code specifies how to format these and what constitutes valid hybrid publication.

How often do these rules change?

Major updates happen every 6-10 years at International Botanical Congresses. Minor corrections and clarifications happen continuously through official notifications. In real terms, the most recent was the Shenzhen Code in 2018. The code is a living document, but changes are carefully vetted.

Can I just make up a name for my pet’s seaweed?

You can write it down. Which means you can even publish it in a blog post. But it won’t be valid under the code unless you meet publication requirements. Other researchers can’t officially recognize it.

use the Power of Nomenclatural Registries

While the core databases mentioned earlier (IPNI, Index Fungorum, AlgaeBase) give you the baseline for published names, the broader nomenclatural infrastructure includes dedicated registries that track every single epithet ever coined. Practically speaking, zooBank, for example, is the official online hub for animal taxonomy, and it integrates with the ICZN. When you submit a new name for an animal, you must register it in ZooBank; the record automatically links the name to its original description, the author citation, and any subsequent changes.

For plants, the Botanical Registry (part of the International Plant Names Index) offers a similar service. Plus, by depositing a new combination or a conserved name, you gain a permanent digital fingerprint that can be cited in future publications. This step is especially valuable when you are dealing with poorly known groups where type specimens are scarce; a registered name provides a clear anchor for anyone trying to trace the taxon’s history.

Master the Art of Citation

The author citation attached to a name is not decorative—it tells you who first validly published the epithet and under what conditions. A common pitfall is to drop or alter the citation when creating a new combination. As an example, moving Acer pseudoplatanus* into the genus Acer* as Acer pseudoplatanus* (L.) Mill. retains the original author “L.Which means ” for the basionym and adds “Mill. ” for the subsequent combination. Mis‑citing can render a name invalid, because the code requires that the epithet be linked to the exact original publication.

When you draft a manuscript, double‑check every citation against the original source. Many taxonomic databases now provide clickable links to the original page scans, which eliminates guesswork. If you are uncertain about the exact author list, consult the International Plant Names Index entry or the Index Fungorum record; both include the full citation details.

Use Electronic Publishing Platforms Wisely

Since the 2012 amendments to the ICBN, electronic-only publications are permissible, provided they meet the “permanent availability” criterion. Think about it: this means the work must be hosted on a platform with a stable URL, an ISSN or similar identifier, and a clear statement that the content will not be removed or altered. Journals such as PhytoKeys* or MycoBank* satisfy these requirements, and their articles are automatically deposited in the relevant registries.

If you opt for a pre‑print server (e., arXiv, bioRxiv), you must later publish the taxonomic description in a journal that fulfills the permanence rule; otherwise, the name will be considered not effectively published. g.A practical workflow is to draft the description on a pre‑print, then submit it to a recognized taxonomic journal that assigns a DOI, thereby satisfying both the electronic and permanence standards.

Conduct a “Nomenclatural Health Check” Before Publishing

Before you submit a new name, run a quick checklist:

Is the name already in use? Search the relevant registry (IPNI, ZooBank, AlgaeBase) for exact matches and for homonyms.
Does the basionym meet the code’s requirements? Verify that the original publication includes a clear diagnosis, a designated type, and the necessary registration.
Have you correctly formatted the author citation? Include all relevant authors and the correct punctuation (e.g., “(Smith) Jones & Patel”).
Is the description sufficient? The code demands a concise statement of the taxon’s distinguishing characters, the location of the type specimen, and, when applicable, a reference to a nomenclatural type.
Have you registered the name? For animals, deposit the name in ZooBank; for plants, submit to the IPNI portal; for fungi, use MycoBank.

Running through these steps saves time later, prevents retroactive invalidation, and demonstrates respect for the community’s standards.

Collaborate With Taxonomic Experts

Even seasoned taxonomists can overlook subtle nomenclatural nuances. When in doubt, reach out to the curators of the relevant herbaria or the editors of the journal you intend to submit to. Here's the thing — many institutions now operate “nomenclature help desks” where you can upload a draft description and receive feedback on compliance with the code. Such collaborations also increase the visibility of your work, as co‑authorship with recognized experts lends credibility.

Keep an Eye on Ongoing Amendments

The code is periodically revised at International Botanical Congresses (IBC) or International Zoological Congresses. Staying informed about these updates can prevent inadvertent violations. The most recent major revision for plants was the Shenzhen Code (2018), which introduced provisions for electronic publishing, tightened rules on conserved names, and clarified the status of “relict” names. Subscribe to the official newsletters of the relevant International Committee for the Taxonomy of Plants (ICTP) or the International Commission on Zoological Nomenclature (ICZN) to receive timely notifications.

Conclusion

Adhering to the nomenclatural code is more than a bureaucratic exercise; it is the foundation upon which the entire edifice of biological classification rests. When these practices become routine, the scientific literature gains consistency, researchers avoid unnecessary retractions, and the collective knowledge of biodiversity becomes more reliable and cumulative. The practical steps outlined above—leveraging registries, verifying citations, publishing electronically with permanence, performing a nomenclatural health check, collaborating with experts, and staying current with code amendments—provide a clear roadmap for anyone working with taxonomic names. By using the appropriate databases, mastering label reading, respecting citation standards, and ensuring that every new name is both novel and validly published, researchers create a stable, interoperable system that benefits taxonomy, ecology, evolution, and even applied fields such as agriculture and medicine. In short, mastering the rules empowers you to contribute meaningfully to the enduring story of life on Earth.