DISCLAIMER: Don't believe anything I or any body else tells you about edible wild plants. Don't eat edible wild plants based on what you see in a book or on the inter-net. Get a qualified instructor to show you the plants, and don't eat them until the instructor shows you how to prepare them, and then eats them him or herself. Be aware that you may be allergic to a plant that someone else can eat without harm. Be sure that any plants that you gather have not been sprayed with pesticides or herbicides.
While visiting my daughter out north of Austin, I took a little walk out back and came across a great summer edible; Prickly Pear cactus. In the spring you can harvest the pads of the prickly pear and after removing the spines, you can peal the pads, slice then, and eat them. You can eat the pads raw, or you can dredge them in corn meal and fry them. The fried pads taste kind of like fried okra. Pictured below: Prickly Pear Cactus.
As the summer wears on the prickly pear develops fruits on it. At first the fruits are green, but as they ripen they turn red. These ripe fruits have a sweet, tangy, citrus taste. Pictured below: top, green fruits; bottom, ripe fruit.
To harvest the fruits, cut them off of the plants with a knife. Be careful of the spines on the pads and the stickers on the fruits. You can remove the stickers from the fruits by wiping the fruits down thoroughly with a cloth. Pictured below: Harvested fruit on knife point.
Once the stickers have been removed you can split the fruits in half. The fruits have a little meat to them and a large gooey mass of seeds in the middle. Pictured below: Split fruit.
Use your fingers to bend the fruit halves open and munch out the inside with your teeth. Don’t skip the seeds. Just suck the sweet goo from around them and spit the seeds out. Pictured below: top, Fruit opened and ready to eat; bottom, Munching on Prickly Pear fruit.