Here are the basic rules of foraging. Memorize them now should there ever come a time when you need to have this it will be there.
1. Do NOT collect plants closer then 200 feet from a road. Many times you can literally see the difference in the plants.
2.NEVER collect from areas that have been sprayed with herbicides,pesticides, or chemicals.
3. ALWAYS be familiar with dangerous plants in the area.
4.Positively Identify all plants you intend to use for food or medicine. Checking against 3 references with good illustrations.
So that is easy sneezy...no problem...:)
Wild Crafting is the oldest occupation known to mankind. Knowing it means that you will never worry about starving to death.
So Here I'm going to spell out the basics of it, the rules of thumb, and how to distinguish between poisonous plants and good plants.
The very first rule of thumb is find your info from 3 sources. so if you are wanting to know how a plant is used and you are not sure if it can be used internally find it from 3 sources. So for example...I will use St. Johns wort. In this case I'm using herb books and not the Internet.
St. Johns wort:
The Herb Bible basically tells me the history of the Plant, that it is a muscle relaxer,used for depression relieves cramping,promotes healing of the skin and helps fight viral infections.
It tells me how to take it and it tells me how much to take. It also says to never take it if using other anti depressants.
The Herbal Medicine makers Handbook tells me more information- It says that it is Nervine. Taken internally it has it has a sedative and pain relieving effect.
Then we get to : The Essential Wild Food Survival Guide: Here Linda has St. Johns wort listed in the poisonous plant section. Here is what she said: Known for medicinal value since biblical days. Primary Use-astringent and salves for bruises wounds and anti-inflammatory Characteristics: leaves shaped like lungs with many holes in them. Plant grows 1 1/2 to 3 feet tall. 5 petaled flowers. From a distance shape is similar to the pocomoonshine variety of goldenrod. Poison.
So my conclusion to this would be never eat it fresh as a survival food. Since you can buy St. John wort over the counter in tablet form, it is taken internally. However...being that it is a plant used to treat depression I would tend to not mess around with it and take Valerian root for any form of anti depressant /calming drug that i would need.
However; know this: I am not saying that it is not good to take internally as you will find it in tablet form in the health food stores. I am saying that logically, i would not use it as a survival food nor will i make a tincture out of it.I do use it in salve making as there is not a salve i have made with out it in it.If I had to i would grind it up to take as a powder. But I would only do that if i was digging out a bullet or some such with no Valerian Root in the house.
I hope this makes sense :)
Now lets say you have no books, no references and your out in the wild starving to death... you have to figure out if you can eat a plant or more importantly serve that plant to the people that you love to eat:
1. Take a piece of the plant and roll it around in your fingers. smell it. pitch it if you have any warning signals in regards to how it smells. If you like the smell of it rub a portion of it on your upper gumsabove the teeth.
2. Wait 20 minutes
3.Check for burning, nausea, stinging, itching.Poisonous plants USUALLY produce one or more of these symptoms.
4.If there is no negative reaction make the plant into a weak tea. steep for 10 minutes. (Must be 10 minutes) ingest a small amount.
5. Wait another 20 minutes. check for any irritation. If there are none reheat the tea and finish.
6. Keep all samples away from children and pets.
7.Remember that heating and boiling a plant does not always destroy toxicity
Also NEVER be intimidated by a plant: Plants were given to you. Not you to the plants. There is however, a certain understanding and connection that we have with them. It is a very hard thing to explain with out sounding like a nut. Maybe the best word that can be used is the word : RESPECT. with highest esteem following along right behind that. I will not destroy something that i hold in high esteem. but we will get into that when I explain gathering to you.