Lemon grass is a wonderful herb that is used in soups and other recipes. It has a citrus flavor and can be used to help with digestion. You can see a picture of it here Grass, Lemon
Wheat grass looks similar to lemon grass, but this is the one that is known for its health benefits. Taken in either juice or tablet form, it is said to heal many different ailments. Its main function is to cleanse and purify the body. This strain of wheat grass is green and does not look like the common wheat that you see in the fields.
I hope this info is helpful. Let me know if you have any other questions.