Although the characters (called "features" in the keys) in Features Available are listed in a particular order, it's up to you to choose characters in the order you wish. It's best, however, to choose the simplest or most obvious characters you can easily address first.
In looking through the characters, you may not understand a character, you may not be sure which state of a character to choose, or a character or state may not be clear on your specimen. It's better to skip the character in such cases. Do not guess!
Also, skip characters that do not apply to your specimen, such as a seed character if your specimen is a fruit. Additionally, skip characters that are not relevant, such as a character that refers to a part on your disseminule that is broken off. This is a common occurrence in some taxa, such as grasses, in which the florets may be damaged.
As you work through the list of Features Available, you may find some characters or character states that you do not understand. If so, review the character notes page attached to each character name. These pages contain explanatory notes, state illustrations or photographic examples, and recommendations for best use of the character. In fact, it's a good idea to check the character notes before using any character the first time, and to become familiar with the notes for all the characters.
Lucid allows you to choose multiple states of a character. You would do this if a) the disseminules in your sample exhibit more than one state; for example, if some seeds are yellow and some are brown, or if a single disseminule is half brown and half yellow; or b) your seeds are all yellowish-brown. In all these situations, you would choose both the yellow and brown states.
Consider all the states for a character and carefully choose the state or states that match, if any.
Some characters are numeric, requiring you to enter a number based on your measurement or count. Be sure to measure accurately, as some seeds are very small and sizes may be less than 1 mm. In general, for measurements in mm (as opposed to cm), round to the nearest 0.1 mm, not to the nearest mm. Enter a range of sizes if relevant, and do not approximate.
After you have selected several character states and most of the taxa have been discarded, you can use the Lucid Player 'Best' tool. The Best algorithm will assess which of the remaining characters and states available will best reduce the list of Entities Remaining. Using one or another of the Best characters will give you the most efficient next step.
If after choosing states, there is only one taxon left in Entities Remaining, you are not done! You should check the description and images and any remarks about identification on the associated fact sheet to confirm that your disseminule matches or is very similar to the FNW taxon. If that fact sheet includes images of similar-looking species, compare your disseminule to those species as well since Similar Species that are not FNW taxa are not in the keys.
Because the taxa covered in this tool represent disparate families, and because disseminules in certain groups look extremely similar and are very difficult to differentiate, arriving at one taxon remaining does not necessarily mean that your disseminule is that FNW taxon. Rather, it may indicate that your disseminule is one that looks very similar to the FNW taxon. You may then be able to continue your identification further by consulting references particular to that group. Or, you may be able to confirm by visual comparison and descriptive information, that your disseminule is not a FNW taxon!
It is quite possible that even after addressing all the characters you can, you would not be able to reduce the number of taxa in Entities Remaining beyond a short list. This may happen frequently in this key because most of the characters are quite general, and because the key includes both species- and genus-level taxa. Also, some of the FNW taxa (for example those in the same genus) are quite hard to differentiate. Again, consult the associated resources. Often, looking through the images of the remaining taxa can be a faster way to make a determination than trying to find a character that will discriminate among them. Remember, these images can be accessed from the fact sheets or the photo galleries while still in the key.
If you end up with no taxa in Entities Remaining, it may mean you made a mistake choosing character states. Review your chosen character states and delete any you are dubious about. Then consult the fact sheets as above. In this key, however, it would not be an unusual occurrence for all the taxa to be discarded, if your disseminule is not a FNW! In this case, deleting a chosen character state can allow you to compare your disseminule to the taxa returned to Entities Remaining to check if it is or is not one of those taxa. The returned taxa may be different depending on which state you delete.
If one or several taxa remain in Entities Remaining, it may be the case that your disseminule is not a FNW taxon, but one that looks similar to a FNW taxon. Be aware of this and check the image galleries and fact sheets of the remaining FNW taxa for Similar Species. If your disseminule is similar, it may or may not be depicted, although an effort has been made in this tool to include similar-looking species likely to be encountered.
It is also possible, however, that your disseminule is similar to a FNW taxon, but that the FNW taxon does not appear in Entities Remaining. This could happen if, for example, although it looks similar, it is much bigger than the FNW taxon, and you used the length character. A strategy to use in this case (as mentioned above) is to delete a state chosen and then compare your disseminule to the taxa returned to Entities Remaining. The returned taxa may be different depending on which state you delete.
You can browse through the fact sheets for all the taxa, independently of the interactive keys. Although the previous/next buttons on individual fact sheets work by going through the FNW taxa alphabetically by family and then by genus, on the Fact Sheets page there is a mechanism for searching the taxa aphabetically by genus, independent of family. So, if you already know the family to which your disseminule belongs, you may be able to make an identification by checking the descriptions and images for that family only. Browsing these pages in general is also a way to familiarize yourself with all the FNW taxa.
For further assistance about how to use Lucid, consult 'Help' from the Lucid interactive key menu.