They have no descendants. Grasses Grasses are a huge family today, but they probably started out as just a simple little plant. Grasses live where there is not enough rainfall to support forests. Over millions of years they have diversified into a huge family of varied plants, plants which support many of the life forms on earth. Corn is a grass.
Wheat is a grass.
Rye and barley and rice are grasses. There are pasture grasses, such as the tall, vigorous grasses that covered the prairies. There are shorter grasses for drier places, huge grasses like pampas grass, decorative grasses, alpine grasses, and so on. All of them have descended from a common ancestor. Grasses have been successful because they have found niches, which are places where there are available resources.