How should you use the key?
- Look for the features listed in capitals, they are the simplest and often the most effective features.
- Answer the plant form question (herb, tree etc.).
- Then answer questions about the form of the leaves, whether they are simple or compound, and whether the margins are entire, lobed, or toothed.
- If you have flowers, attempt to answer questions such as stamen and petal number as these will take you quickly to an answer.
- If your plant lacks flowers or fruit, choose the subset of characters 'vegetative only'.
- If you already know that your plant belongs to a large common family (like the daisy family), look at the bottom of the list of features where you can choose from the largest 10 families.
- Use the 'Best' tool to find which question will discriminate best amongst the remaining genera. You may not be able to answer the feature that is highlighted. If so press the 'Next Best' button (as often as you want) and look for something you can answer.
- If at some point answering 'Best' questions seems to get you no closer to a single genus and you have half a dozen genera or less, shuffle through the images for a match to your specimen. The green arrows above the images allow you to do this without returning to the key itself.
If you think the genera remaining don't include the plant you have, be prepared to un-tick some of your answers, and try answering different questions. Note what difference this makes to the list of remaining genera, and look for a consensus. There are several sources of possible error in using this key. The dataset for this key is huge (about 64,000 pieces of information) and taken from a variety of sources. Some of this information is incorrect: random sampling of leaf lengths and widths indicates about 5% of specimens lie outside the ranges provided here. Secondly, you may have mis-scored or mis-interpreted a feature. Check explanations accompanying the features. For leaf length and width, you can enter a range (e.g. for a specimen with a leaf 25 mm long, try entering '20-30 mm' for leaf length).
If you are unsure whether your plant is known in the wild, but you would still like to use the key to place the plant in a family or genus, use questions like stamen number and ovary position which are more constant for families and genera. and be cautious with features like leaf length and width.
Be cautious in using island distribution for non-native plants, as these are likely to occur beyond their known range, especially casuals. Island distribution should be reliable for native genera.
Be cautious in using habitat characters. Genera have been scored for the habitats they have been recorded in, but particularly for naturalised and casual plants, they are likely to turn up in new habitats.
If you have difficulties getting the key to work, or would like further help on how to operate the key, use the Help button on this key's front page.