You have to cook the fiddleheads first to remove the skikimic acid, a type of tannin which makes them very bitter if not cooked properly. Boiling for about 5 minutes, changing the water and then boiling another 5 minutes will remove the acidic properties. Fiddleheads taste a bit like a combination of brussel sprouts and broccoli. I've heard they are very healthy for you, as are most "green" things. Acorns for oak trees are similar in the need to cook them first, especially those acorns from the red oak family. White oak species have less tannins are a sweeter, some trees produce acorns so sweet you can eat them raw. Red oak acorns if boiled in 3-4 changes of water are palatable and if then roasted and ground make a very tasty and nutritious flour. Many Native American tribes in the east relied heavily on acorn crops, especially before agriculture became more prevalent.

Morels do grow in the east. I am not sure they are quite as common as they are in the wooded areas of the Midwest. I have found some, but I can't ever seem to find enough consistently to make meals out of them. Perhaps my hunting grounds are not as good as I know a few who have better luck. Morels have specific habitat types they prefer.