Poaceae

From Wikipedia, the free encyclopedia.

? True grasses
Flowering head of Meadow Foxtail (Alopecurus pratensis), with stamens exserted at anthesis
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Poales Family: Poaceae (R.Br.) Barnhart
Subfamilies
There are 7 subfamilies: Subfamily Arundinoideae Subfamily Bambusoideae Subfamily Centothecoideae Subfamily Chloridoideae Subfamily Panicoideae Subfamily Pooideae Subfamily Stipoideae

The true grasses are monocotyledonous plants (Class Liliopsida) in the Family Poaceae, also known as Gramineae. There are about 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.
• Small, wind-pollinated flowers (called florets) sheathed inside two glumes (bracts), lacking petals, and grouped into spikelets, these arranged in a panicle, raceme, spike, or head.
• Fruit that is a caryopsis.

Cultivation and uses

Agricultural grasses grown for human food production are called cereals. Cereals constitute the major source of food energy for humans and perhaps the major source of protein, and include rice in South and Southeast Asia, maize in Central and South America, and wheat and barley in the Americas and North Eurasia. Many other grasses are also grown for forage and fodder for animal food, particularly for sheep and cattle.

Some commonly known grass plants are:

• maize
• wheat
• rice
• rye
• ryegrass
• sugarcane
• barley
• bamboo

See also

• agrostology
• grass
• Meadow-grass
• Marram grass
• Bahia grass

External links and references

• Definitions of Grass structures
• Poaceae in L. Watson and M.J. Dallwitz] (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval.
• L. Watson and M. J. Dallwitz (1992 onwards). The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references.