The pic below shows three of my favorite early spring greens: Winter cress, peppergrass and plantain (left to right and top to bottom).
Winter cress is a hardy plant that grows literally everywhere I walk in Milwaukee. I have seen it in old garden beds, along bike trails and even in yards. It has very shiny, dark green leaves and at this point in the season has grown stalks with flower buds that resemble very small florets of broccoli. These are very bitter when eaten raw, as are the leaves; when cooked, however, they become very palatable to anyone who likes greens and I highly recommend them.
Pic from (http://www.rhodysurvivalist.com)
Click the tofu for a recipe that winter cress will make even better!