While we hope you never find yourself in the kind of survival situation that has you foraging for wild plants to eat, if you should find yourself in such a situation the Universal Edibility Test can save your life.
Photo by BarefootGardener.
The Universal Edibility Test is a series of tests you can use to determine if a plant is safe to consume. At the site HowStuffWorks they've outlined the prongs of the test and how you can apply it safely in the field. The initial part of the test is to separate the item into its parts like leaves, stems, roots, buds, and flowers—many plants have edible and inedible portions. The first actual experiment is the contact test:
First you need to perform a contact test. If it's not good for your skin, it's not good for your belly. Crush only one of the plant parts and rub it on the inside of your wrist or elbow for 15 minutes. Now wait for eight hours. If you have a reaction at the point of contact, then you don't want to continue with this part of the plant. A burning sensation, redness, welts and bumps are all bad signs. While you wait, you can drink water, but don't eat anything. If there is no topical reaction after eight hours, move along to the next step.
From there you increase your exposure incrementally to see if you have any adverse reactions. Check out the full guide at HowStuffWorks to get tips on each step of the test and how to perform it safely. Make sure to check out their list on plant warning signs—never eat anything with thorns, milky sap, or that smells like almonds, for instance.
In addition to knowing how to test for edibility it's also valuable to read up on the topic. The photo shown above is of Queen Anne's Lace, a European flower that is found all over the continental United States. The roots of the plant are edible and very similar to carrots—Queen Anne's Lace is actually an ancestor to the modern carrot. The stems and leaves however are mildly toxic. Another plant that looks similar to Queen Anne's Lace is Water Hemlock—an extremely poisonous plant that is potent enough to kill cattle.