Poaceae is the fifth-largest plant family, following Asteraceae, Orchidaceae, Fabaceae, and Rubiaceae, with approximately 780 genera and 12,000 species.

The Poaceae family is the most important to the economy because they feed animals that make meat and provide staple foods from domesticated cereal crops like maize, wheat, rice, barley, and millet. They provide just over half (51%) of all dietary energy through direct human consumption; rice gives 20%,[6] wheat supplies 20%, maize (corn) 5.5%, and different grains 6%[citation needed]. Bamboo, thatch, and straw—all members of the Poaceae—are utilized as building materials. Others can provide biofuel, primarily through the ethanol production from maize.

Grasses have narrow alternate leaves borne in two ranks and hollow stems, with the exception of the nodes. A leaf-sheath is formed when the lower part of each leaf surrounds the stem. An adaptation that enables it to deal with frequent grazing is the leaf’s tendency to grow from the base of the blade.

With the exception of Greenland and Antarctica, it is estimated that grasslands like savannah and prairie, which are dominated by grasses, make up 40.5% of the world’s land area. Numerous other habitats, such as wetlands, forests, and tundra, also contain grazing grasses, which contribute significantly to the vegetation.

Seagrasses, rushes, and sedges are examples of plants that do not belong to the family “grasses,” despite being commonly referred to as such. Seagrasses belong to the order Alismatales, whereas rushes and sedges belong to the order Poales, which is related to the Poaceae. Nonetheless, every one of them have a place with the monocot gathering of plants.