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What did you find?
Eight step-by-step identification tools, each built around what you can actually see and test rather than what a photograph happens to look like. Pick the one that matches what is in front of you.
What rock is this?Hardness, streak, lustre and cleavage — the tests that actually separate minerals.
Rocks & minerals →
What snake is this?Start with your state. Most have one or two venomous species, and several have none.
Snakes →
What spider is this?Of ~3,500 US species, two groups matter medically. The web narrows it fastest.
Spiders →
What's wrong with my plant?Which plant, what the damage looks like, and whether it started at the bottom or the top.
Plant problems →
What kind of mould is this?The species rarely changes what you should do. Finding the water always does.
Mould →
What mushroom is this?Spore print, what's under the cap, and the base of the stem you have to dig for.
Mushrooms →
What tree is this?Opposite or alternate leaves removes most species before you look at the leaf itself.
Trees →
What fish is this?The confusable pairs, side by side — and a reminder that limits are set by your state.
Fish →How this works
The same method in every section, because it is the method that does the work.
Every question is optional. Answer three and the list of possibilities is usually short enough to check by hand.
It varies with age, light, water and season. Shape, arrangement, texture and location do not, which is why the questions ask about those instead.
Where an answer cannot be trusted — a mushroom you intend to eat, a snake in reach, a bite that is spreading — the page says so before it says anything else.
Latest
Across every section. All guides · all articles
- fishLargemouth, Smallmouth or Spotted? Three ChecksThe three black bass share water and often share a limit — but not always. Jaw length, stripe direction and a rough patch on the tongue separate all three in seconds.
- treesOpposite or Alternate? The Question That Halves the AnswerOnly a handful of North American trees have opposite leaves. Checking this first eliminates most species in seconds — here is how to read it, and the mnemonic that lists them.
- mushroomsHow to Take a Spore Print — and Why It Matters So MuchA spore print costs nothing, takes a few hours, and separates several deadly mushrooms from the edible species they resemble. Here is how, and what each colour rules out.
- moldToxic Black Mould: What the Evidence Actually SaysStachybotrys is real, produces mycotoxins, and needs soaked material to grow. What it is not is a separate category of danger requiring a different response.
- plantsOverwatering or Underwatering? The Leaves Won't Tell YouBoth make a plant droop and yellow, and the treatments are opposites. The soil, the leaf texture and the recovery time separate them in under a minute.
- spidersDo Brown Recluses Live Where You Do? Probably NotBrown recluses live in a small part of the United States, and are absent from California, Florida, the Pacific Northwest and the northeast — despite constant reports.
Questions people ask
›Is this free, and do I have to sign up?
Everything on the site is free, with no account and no email. Nothing you select is sent to a server — the identification runs in your browser, which is also why it keeps working after the page has loaded and why there is nothing here that could keep a copy of what you entered.
›Why not just use a photo app?
Use both, for different moments. Photo identification is fast and good at distinctive, well-formed specimens. It is weak at exactly the cases people struggle with: worn, damaged, juvenile or partly-hidden things, and lookalikes that differ in a feature the camera cannot see. The questions here work from properties you can test or observe directly, which is what separates the hard cases.
›How accurate is it?
It narrows; it does not conclude. Answering three good questions usually takes a list of dozens down to a handful, and the handful is where your own eyes take over. Where being wrong carries a real cost — eating a mushroom, approaching a snake, a bite that is spreading — the page says so before it says anything else, and points at someone qualified.
›Why are there eight different subjects on one site?
Because they are one question asked eight ways. Somebody has found a thing — a rock, a snake in the yard, spots on a leaf, something black in the bathroom — and wants to know what it is. The method is the same each time: ask about characters that do not vary, ignore the ones that do, and be honest about where the answer stops.
›Who writes this?
An editorial team, and every guide and article carries a byline and a date it was last reviewed. The about page sets out how entries are written, what the site will not do, and how to report something that is wrong — corrections update the review date rather than being made silently.
›Are there apps?
Yes — a separate free iPhone app for each subject, which does the part a website cannot: reading a photograph, in the field, with no connection. Each section links to its own. Nothing on this site requires one.