On Authority, We Rhinos are told that Grasses are 60 million years old. Maybe more, maybe less. Either way, they have been successful, over time developing in many directions, most of them edible.
Rhinos eat a lot of Grass, daily. What may not look like Grass to a casual observer, still counts as Grass at suppertime.
Technicalities aside, Rhinos sing the praises of Grass at all meals, including teatime. We feel it is the least We can do to be grateful and encouraging.