Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this date back to 66 million years ago.Wu, You & Li (in press) described grass microfossils extracted from a specimen of the hadrosauroid dinosaur Equijubus normani from the Early Cretaceous (Albian) Zhonggou Formation (China).
Many types of animals eat grass as their main source of food, and are called graminivores – these include cattle, sheep, horses, rabbits and many invertebrates, such as grasshoppers and the caterpillars of many brown butterflies.
Grasses are also eaten by omnivorous or even occasionally by primarily carnivorous animals.
This low growth point evolved in response to grazing animals and allows grasses to be grazed or mown regularly without severe damage to the plant.
The success of the grasses lies in part in their morphology and growth processes and in part in their physiological diversity.
Grasses are unusual in that the meristem is located near the bottom of the plant; hence, they can quickly recover from cropping at the top.
The evolution of large grazing animals in the Cenozoic contributed to the spread of grasses.based on the tribe Poeae described in 1814 by Robert Brown, and the type genus Poa described in 1753 by Carl Linnaeus.The term is derived from the Ancient Greek πόα (póa, “fodder”).Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses.Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns and pasture.With around 780 genera and around 12,000 species, Grasses are also an important part of the vegetation in many other habitats, including wetlands, forests and tundra.