The grass family, known scientifically as either the Poaceae or Gramineae, is one of the four largest families of flowering plants, with approximately five hundred genera and ten thousand species. Grasses range from tiny inconspicuous herbs less than 5 centimeters tall to the giant bamboos, which grow to 40 meters tall. The family is undoubtedly the most important flowering plant family to humans, directly or indirectly providing more than three-quarters of our food. In addition, grasses are major producers of oxygen and a large component of environmental filtering processes due to the enormous geographic range, spatial coverage, and biomass of grasses on Earth. Grasses are the greatest single source of wealth in the world.

Grasses are the greatest single source of wealth in the world.

Morphology

All grasses have fibrous secondary roots (the primary root disappears early in development) and can be annual or perennial, in which case they usually...