Taxonomic Keys

A key is a device that, when built and used correctly, allows a person to identify an organism. Keys are devices that consist of a succession of opposing or contradicting assertions or propositions that require the identifier to make comparisons and conclusions based on the key’s claims in relation to the material to be identified. As a result, a taxonomic key is a tool for quickly and readily determining which species a plant belongs to. 

Taxonomic keys

A taxonomy key is a straightforward method for identifying a single item. A taxonomy key is one of the most important tools available to scientists trying to identify an unknown organism. Systematics employ keys to identify existing species and determine whether they’ve discovered anything completely new. The key is made up of a number of options based on the plant specimen’s observable characteristics. It allows you to choose between two conflicting assertions, with one being accepted and the other being rejected. A couplet is a single pair of conflicting claims, and each sentence in a couplet is referred to as a lead. One can finally get at the name of the unknown plant by making the correct option at each level of the key. 

Types of taxonomic keys

There are two types of taxonomic keys :- 

• Dichotomous and

• Poly clave (also called Multiple Access or Synoptic)

Dichotomous

Dichotomous keys are those in which the options only allow for two (mutually exclusive) possible couplets. When creating a key, opposing traits are chosen to split the entire range of viable species into smaller and smaller groupings, i.e. the statements normally start broad and shrink as more choices are necessary. Dichotomous keys are divided into two categories. They differ in the way the couplets are grouped and how the user is guided through the options .

Indented Keys (also called yoked)

Indent the couplet’s options (leads) from the left margin by the same amount. The couplet’s two options are commonly referred to as 1 and 1′ or la and lb. It is not required that the options be numbered, but it is beneficial. Following the lead that was selected, the user moves on to the next indented couplet .

Bracketed Keys

Both options are displayed side by side. The couplet’s options must be numbered (or lettered). If the prior couplet is given, it is quite beneficial. This key has the exact same options as the first one. The options are separated, yet the connections are obvious. While this key is more complex to create, it provides the user with more information .

Poly clave keys

Multiple access, poly clave, or synoptic keys are another sort of key that is a relatively new alternative to dichotomous keys and is becoming increasingly popular, especially because of their simplicity of computerization. These keys have the advantage of allowing the user to enter the key at any time. This key is based on the elimination procedure for identifying organisms. There are a sequence of characters and character states in a written poly clave key. Each state is followed by a number or code indicating which species have that trait.

How to use taxonomic keys

• For the materials to be identified, appropriate keys should be chosen. A flora, manual, guide handbook, monograph, or revision may contain the keys. If the location of an unknown plant is known, a flora, guide, or handbook dealing with plants native to that region can be used.

•  Before using the key, read the introductory comments on format details, abbreviations, and so on .

• Before making a decision, both leads of a couplet should be read. Despite the fact that the first lead appears to describe the unknown material, the second lead may be more relevant.

• A glossary should be used to look up the definitions of terms that are unfamiliar.

• When measurements are used in the key, numerous identical structures should be measured, e.g. several leaves rather than a single leaf. A single observation should not be used to make a decision. Rather, it’s common to want to look at a few different examples.

• Reading a description and comparing the specimen to an illustration or an authentically named herbarium specimen should be used to verify the results.

Taxonomic keys example

• In tree identification, a dichotomous key might ask whether the tree has leaves or needles. 

• The dynamic species list and key generator from Symbiota

• iNaturalist’s Sagehen Creek Field Station Wildflower Guide

Conclusion

A taxonomy key is a straightforward tool for identifying live organisms. Both monographs and flora are prepared with the help of the keys. The monograph contains thorough information about one taxon, which could be a family, genus, order, class, or other classification.