Back in the Midwest as a child I used to go into my back yard and graze on this plant.
It has small yellow flower and little green banana shaped pods with seeds. They were sour when you ate them. They grew in clumps and they are not Dandelions.
I think it might be a type of sorrel:
http://www.lib.ksu.edu/wildflower/yellowsorrel.html
I remember eating it, too, although I usually confined myself to the flowers. I grew up in Indiana, but there’s a similar plant here in California that my husband remembers munching on. He called it “sourgrass.”
http://www.cloudnet.com/~djeans/FlwPlant/YWdSorrel.htm
Here is more on them for you humans who want to graze on some good eats.