My first encounter with yellow wood sorrel wasn't in the wild, but at Epiphany Farm-to-Fork restaurant in Tuscaloosa, where I'm certain the chef used some in a dish. Yellow wood sorrel is identifiable by its clover-like leaves and small yellow flowers. It visually complements a dish yet also has a delicious taste.
In the wild, you can usually find it throughout the U.S. and in other parts of the world in forest, woods, or other areas with lots of shade. I found a ton of it when hiking the trail around Lake Lurleen in Tuscaloosa. Many people describe the taste as lemon-like, but to me and my friend Joya it has more of a sour-apple, tangy taste. It's really delicious, and a good addition to salads or other dishes. It provides a bit of nice texture and that unexpected tanginess.
Yellow wood-sorrel also has health and medicinal benefits, many of which are outlined on Harrison Murray's blog "Bushcraft." It's high in Vitamin C, and it also has diuretic and cooling properties. Murray cautions that it should be eaten in moderation, though, because it's high in potassium oxalate and oxalic acid.
In small amounts, it should be safe, healthy, and delicious. The main challenge (as with dandelions) is simply getting it from the ground to your table before it starts to wilt!