Working tools · Trees · New
What tree is that?
Stand under it, look at a leaf, look at the bark, and answer what you can actually see. Skip anything you can't. The key keeps a running count of which California trees still fit and shows you why.
Start with a leaf
Eight questions at most, usually fewer. Every answer narrows the list; a wrong guess doesn't throw a tree out, it just moves it down. You can change any answer later from the strip at the top.
Check what your app said
A plant-ID app gave you a name. Type it here and the key shows the leaf, bark and fruit that tree should have, so you can confirm the name or doubt it.
The key needs JavaScript to run. Turn it on and reload the page, and the questions will appear here.
0 trees still match
How this key works and where the pictures come from
A field key asks you about features you can see and uses each answer to cut the list of possibilities. Ours is a soft key: a tree that disagrees with one of your answers isn't thrown out, it drops down the ranking. That matters outdoors, because bark changes with age, a leaf edge can be smooth on one branch and toothed on the next, and the fruit may be on the ground or not there at all. The count in the footer is the number of trees that agree with everything you've said so far; the results also list the near misses and tell you exactly which answer each one disagreed with.
The order of the questions isn't fixed. The first question is always the leaf, because everyone can answer it. After that, the key looks at the trees still in play and asks whichever question splits them most evenly, so each answer does as much work as possible. If a question doesn't apply (leaf edge on a pine, say) the key never asks it. You can jump to any question from the strip at the top and change an answer, and the address bar carries your answers, so a result can be shared or revisited with the back button.
The key covers 233 trees found across North America, native and planted. By default it shows only the ones recorded in California: the natives, plus the street and garden trees found everywhere. A checkbox on the start screen widens it to the full list. Every trait value was checked against a published flora, and values no flora states were taken out, so a tree may simply have no entry for a trait rather than a guessed one; the sources for each tree are listed on its page. The Guild corrects misses as readers report them, so a wrong answer from the key is worth a note to us.
The species notes on the results give a few words on what to look for next. For a confident identification, look at the matched tree on iNaturalist, which links from every result, and compare several photos against the tree in front of you. A key narrows; it doesn't decide.
Picture credits
The leaf and tree diagrams on the answer tiles are adapted from the leaf morphology chart by Debivort and McSush, Wikimedia Commons, licensed CC BY-SA 3.0; our redrawn versions carry the same license. The small line icons are the Guild's own.
Species photographs are credited individually beneath each photo with the photographer's name, the license, and a link to the source. Every photo is a resized copy of a photograph its author released under a Creative Commons license that permits reuse with credit (CC0, CC BY or CC BY-SA), drawn from iNaturalist, Wikimedia Commons and Flickr. Copies of photos under CC BY-SA carry the same license. If you are a photographer and believe a credit is wrong, write to us and we'll fix it.