See: List of Poaceae genera
The true grasses are monocot (class Liliopsida) plants of the family Poaceae (formerly Graminae). There are some 600 genera and perhaps 10,000 species of grasses. It is estimated grasslands comprise 20% of the vegetation cover of the earth. This family is the most important of all plant families to human economies, including lawn and forage grasses, the staple food grains grown around the world, and bamboo, widely used for construction throughout Asia.
Grasses generally have the following characteristics:
- Typically hollow stems (called culms), plugged at intervals (the nodes).
- Leaves, arising at nodes, alternate, distichous (in one plane) or rarely spiral, and parallel-veined.
- Leaves differentiated into a lower sheath hugging the stem for a distance and a blade with margin usually entire; a ligule (a membranous appendage or ring of hairs) lies at the junction between sheath and blade.
- Flowers small (called florets), lacking petals, and grouped into spikelets arranged in a panicle, raceme, spike, or head; the flowers wind-pollinated.
- Fruit a caryopsis (also called a grain).
Some commonly known grass plants are: