Cereal and Rice grass

Cereal noun - Grass whose starchy grains are used as food: wheat; rice; rye; oats; maize; buckwheat; millet.

Rice grass and cereal are semantically related. In some cases you can replace phrase "Rice grass" with "Cereal", this terms are similar.

Rice grass noun - Any grass of the genus Oryzopsis.

Cereal and rice grass are semantically related. You can use "Cereal" instead a noun phrase "Rice grass".