Please help me identify 3 more plants on my property!

I have three more plants I'm having trouble finding what they are.

The first one is a purplish green plant that looks like lettuce sorta. It's very low growing until it seeds. It has an extremely long tap root that is very hard to pull out the entire plant. It seems to be very noncompetitive, grows in my non till garden areas when I pull up the grass and weeds and other bare spots in the land. It also is growing in an area we placed gravel. I haven't been pulling it up by the roots because it's so hard. I just pull the leaves when they get big and use them as mulch. I figure they must contain lots of deep nutrients since the tap root is EXTREMELY deep.

second one is a plant with pods very similar to peas. I took a small nibble at a pod and it didn't seem to taste bad. It's a plant, not a tree. I've very curious if it's edible as there are lots and lots growing. The land used to have lots of mesquite which is of course a podded tree. Some are still there. It is not mesquite though, it's just interesting that there would be so much nitrogen fixers(I assume it's a nitrogen fixer as it has pods)

Last one is some kind of tree or perennial bush. It has thorns(I think it's one per leaf). It has different type leafs than any other thorny tree I've seen.

I'd appreciate any help. I've searched and searched myself but these are hard for me to find. Thanks


http://i1062.photobucket.com/albums/t488/nr5p/lettuceweed.jpg

http://i1062.photobucket.com/albums/t488/nr5p/podweed.jpg

http://i1062.photobucket.com/albums/t488/nr5p/thorntree.jpg

First looks like a type of dock - if it is, then it's edible. Look up dock and see if you think that's it.

Second is some type of vetch.

Third looks like hawthorn.

I'd make sure #2 is not locoweed:
http://www.wildflower.org/image_archive/320x240/PCD3538/PCD3538_IMG0079.JPG
Other than that, I am no help. Sorry.

I agree with the general IDs already provided. Furthermore, the dock is probably Rumex sanguineum, Bloody Dock (or a hybrid thereof), and the vetch looks quite a bit like Vicia sativa, which is said to be edible (http://www.arthurleej.com/a-vetch.html). I seem to recall reading about some vetches having varying amounts of not-so-good-for-you chemicals, particularly cardiac glycosides and chemicals that can cause lathyrism, so even if it is common vetch you might still limit your intake just to be safe. You'll have to check back in the late summer or fall to see if the hawthorn fruit is worth eating.

After looking at the picture of the hawthorn again, I noticed another plant at the bottom left which looks a bit like burdock. If it is then I hope you get a chance to enjoy that edible as well!