Ive always wanted to try the inner bark of pine trees. Ive read the Adirondack used to eat it extensively. Considering how common pines are it would make a good survival food.

"They had ceremonies where they would drink gallons of a special drink until they started spewing at both ends. "

Around here we call it Wild Turkey. 

If you are looking for food you can get in the wild in order to survive, why not consider trying this https://www.amazon.com/gp/aw/d/1440598525/ref=mp_s_a_1_4?ie=UTF8&qid=1496113375&...; I don't have it though, but it looks usefull.

There's also some apps you can get along those lines. This thread inspired me to check out a website called foraging texas. While doing that I found out that yaupon holly, which I always just thought of as a good arrow wood is also the only native Texas plant that produces caffiene. Apparently the leaves are slightly sweet as well so they can be brewed into a tasty tea. Very cool.

Yaupon Holly is the only caffeine bearing plant in North America that is safe to make a drink from that I am aware of. 

Yaupon Holly can be prepared two ways.  Easiest is to drop some fresh green leaves in boiling water and let them steep to taste.  That will give you about the same amount of caffeine as coffee.  If you parch the leaves, you get a lot more, something like six times as much.

It tastes like a very dry green tea and a really strong, dry,  green tea with a slightly bitter after taste if you parch them, especially if you parch them too much.  We always added a pint of honey to about 5 gallons of tea if we were going to serve it to someone.

The berries are sweet but they don't add a sweet taste to the drink.

The Black Drink, which has yaupon as a base but with stuff added was the drink that the Native Americans used to purge themselves.

As far as foraging for plants, you really need to go out with someone who knows what plants are which.  There are a lot  of plants that mimic poisonous plants to avoid being eaten.  Some of them, you really can't tell from just pictures.

@Bill 6 times as much as coffee? That sounds dangerous.

@CA- If I remember correctly the inner bark has something like 500 calories per pound.  Doesnt sound worth it. I wouldnt mind trying it though.

One plant I really enjoy is stinging nettles. Really tasty.

Cooking them renders them safe. I used to eat the leaves right off the plants back in Cali. There are different subspecies so some may not be safe to eat raw. Ive only seen two. The ones near me were relatively safe to handle but the ones in the mountains would give a nasty sting that would ache for hours.

Wait until after the first frost and then pick them like crazy.  They make really great cordage then, just wilted but with green leaves, or just starting to turn yellow.  Take them and store them out of the sun but in bundles.  And don't let them get too dry.  And keep them as straight as possible.

Pick the leaves off.  Then roll them lengthwise in your hands to get the pith out.  You should be left with a bunch of long strands almost the length of the plant.  Use that to make cordage just like you make a Flemish twist bowstring..