A couple of credits and comments.
Blast's site on plants is quite good and he has some pretty good links on it. It is well worth taking a look at.

Field guides like Blast's are good to help you start identifying plants.
You still need to make sure you have it right. Finding people with personal experience is getting harder all the time.
Many people today wouldn't be able to identify the food they eat every day if you took them out and stood them in a field of it. (and I am talking about common food plants not exotics)
They would be able to starve in the middle of plenty.


Susan is right and Death Camas is a good example.


There are actually 2 varieties of White Camas with the western one being far more deadly.
But once you know them they are really not hard to tell apart from Camas bulbs.
(and you need to know real camas well enough to know that whatever else you might dig up is not it and not to be gathered)

If you are not careful or are guessing you are more likely to be killed by different varieties of plants we commonly use as food. There are lots of deadly plants in the carrot, bean and pea families as well.

Then there are plants that need to be ripe, ones that can not be ripe, and the ones that need to be specially processed or else they are poison too.

Sometimes even a different part of a regular food plant, or improperly stored food plants can kill.
Potato leaves and stems are deadly and a potato which has gotten enough sunlight to turn green becomes poison.

Some plants are even poison to touch!

You need to be familiar with the plant before gathering a mess of it and eating it.

However there are a lot of good plants that have no poisonous times of the year, poisonous parts or dangerous lookalikes.
So start with some of the safer ones to try.
Don't be too discouraged by some of them.

I see guidebooks that claim some plants can taste delicious if you boil them in a hundred changes of water, but the truth is cattail roots still taste like muddy swamp muck and dandelion greens are still bitter.

One of my favorites is an introduced weed called Lamb's Quarters (Chenopodium alba) because it is so simple. Just use it like spinach.
It grows anywhere there has been any sort of farming and it produces greens all year.
(The seeds can be gathered and ground in enough quantity to be useful as a grain, but that is a bit fiddly for me to bother with.)
It comes up as a weed in most gardens and the young stems and leaves make an excellent green (even better than spinach to me, it is not as gritty).


Please keep the comments coming, I am learning a bit in this thread.