Be on the lookout for wood sorrel (Oxalis spp.) emerging on the edges of your garden, in the woods, along streams and especially in sidewalk cracks. (Though be weary of eating anything growing out of the sidewalk!) All the above ground parts of this plant are edible and make a wonderful addition to salads, sandwiches or soups. Some species even have edible underground tubers! The heart-shaped leaflets are easy to see and the taste is distinctly sour-tangy-lemony-sweet.