The five iron rules

The five rules on the page above are the right five, in the right order, and they are the frame for everything else in this module. This page makes two of them concrete for Britain, because a rule you cannot apply is a rule you will break.

What 100 per cent identification actually means

It does not mean confident. It means having positively identified the plant on features that its dangerous lookalikes cannot share.

The parent page says cross-check three or more features against a regional guide, and that is the method. In practice it means the following, and the list matters because people routinely check the one feature that is least diagnostic.

• Smell. Crush a leaf. Many lookalike pairs separate instantly on smell and on nothing else.
• Stem. Round or ridged, solid or hollow, hairy or smooth, blotched or plain. Cut it across and look.
• Habitat. Wet ground, chalk, woodland, verge. A plant in the wrong place is a reason to stop, not a curiosity.
• Season. What it looks like in April is not what the book photographed in July.
• The whole plant, including the root and the base, not the part you were going to use.

Then the honest test: can you name the lookalike you ruled out, and say what ruled it out? If not, you have recognised a plant rather than identified one, and the parent page's rule says do not use it.

The British plants that kill

The parent page names yarrow and hemlock, elder and pokeweed, pine and yew. Pokeweed is an American plant and is not a British problem. These are.

The foxglove and comfrey pair is the one to sit with, because comfrey is on the very next page of this module as an external remedy, and before either flowers their basal leaves are similar enough that people have confused them. Learn that pair specifically, on real plants, before using comfrey for anything.

And note where the danger is concentrated. Almost all of it is in the plants you would eat or drink, not in the ones you would put on skin. The wound-care page's plantain, honey and yarrow poultices carry a fraction of the risk of any tea.

Why the app on your phone is not the answer

Plant identification applications are genuinely useful for learning, and they are not a safety mechanism.

They work from a photograph, and photographs cannot carry the features that separate the dangerous pairs. No image conveys smell, stem cross-section, root structure, or the feel of a leaf. Those are exactly the features the lookalike tables turn on.

They also give an answer with a confidence figure, which reads as certainty to a person who wants one. A plant identified as probably hogweed is not identified.

Use them the right way round. An app is excellent for generating a hypothesis, which you then confirm against a regional guide, on the features listed above, on the whole plant. It is not for confirming a decision you have already made because you are hungry.

The real answer is a person. A local foraging walk, a botanical society, a county wildlife trust, somebody who has done it for years. One afternoon with somebody who knows the plants in your area is worth every book and app in this section, and the plants you learn that way are the ones you can use with confidence for the rest of your life.

The skin test, and what it does not cover

Rule 2 is a good rule and its limits are worth understanding.

A 24-hour patch test on the inner forearm catches contact allergy, which is common, particularly across the daisy family the parent page names: chamomile, yarrow, calendula, feverfew.

It does not catch anything else. It says nothing about toxicity when swallowed, nothing about interaction with a prescribed medicine, and nothing about a reaction that needs repeat exposure to develop. A plant that passes a patch test is a plant that did not irritate your forearm.

It also does not predict anaphylaxis, which is why anybody with known severe allergy should be more conservative than this rule, not equally conservative. See anaphylaxis.

When rule 5 fires and you cannot reach care

Rule 5 lists the signs that mean this is an antibiotic or hospital problem, and tells you to burn your stored favours to reach real care. That is right, and it leaves the hardest question unanswered.

First, exhaust the routes before concluding they are gone. In almost every British disruption, emergency care is the last thing to fail. Ring 999 even when you think it will not work. Ring 111. Walk to the surgery. Ask a neighbour who drives. Ask whether anybody on the street is a nurse, a paramedic or a pharmacist, which is exactly the inventory the community page told you to build.

Then, if it genuinely cannot be reached, the honest position is this. Nothing in this module is a substitute for an antibiotic in a spreading infection. Plant remedies are the supporting act, as rule 4 says, and pretending otherwise at the moment it matters most would be the worst thing this app could do.

What still helps, and helps genuinely:

• Clean it properly and keep cleaning it. Irrigation with clean water is rule 4 and it remains the single most effective thing available.
• Rest, warmth, and fluids. Being cold, exhausted and dehydrated makes any infection worse.
• Elevate and immobilise an infected limb.
• Mark the edge of the redness with a pen and write the time. This turns an argument about whether it is spreading into an observation, and it is the single most useful thing you can do while waiting.
• Keep trying for help. Circumstances change, roads clear, services come back.

See wound infection and recognising sepsis, which are the pages this rule points at.