Grass

For other uses, see Grass (disambiguation).

Cut grass

Pennisetum setaceum flowers.

Grass is the common word that generally describes monocotyledonous green plants. The family Poaceae (or Gramineae) are the "true grasses" and include most plants grown as grains, for pasture, and for lawns (turf). They include some more specialised crops such as lemongrass, as well as many ornamental plants. They also include plants often recognized to be grasses, such as bamboos, maize or some species of weeds called crab grass.

Use of the term

The term grass can refer to family Poaceae, the 'true grasses', or to grass-like plants which includes the Poaceae and typically also the rushes (Juncaceae) and sedges (Cyperaceae), which somewhat resemble grass. Another, more specific, term for the latter group is graminoid.

Grass may also be used to describe completely unrelated plants, sometimes of similar appearances to grass, with leaves rising vertically from the ground, and sometimes of dissimilar appearance. The term came about in the early 15th century, from the Old English græs, derived from the same root as "grow". A single piece of grass is called a blade.

Importance

Houses with grass roofs in Iceland.

A kangaroo eating grass.

Grass-like plants are among the most versatile life forms. Plants having grass-like structures have existed for millions of years, providing fodder for Cretaceous dinosaurs, whose fossilized dung (coprolite) contains phytoliths of a variety of grasses that include the ancestors of rice and bamboo. Grasses have adapted to conditions in lush rain forests, dry deserts, and cold mountain steppes, and are now the most widespread plant type.

Plants of this type were always important to humans. They were cultivated as food for domesticated animals for up to 10,000 years. (See grass fed beef.) They have been used for paper-making since at least 2400 BC. Now they provide the majority of food crops, and have many other uses, such as feeding animals, and for lawns. There are many minor uses, and grasses are familiar to most human cultures.

Grasses used as an ornamental planting

Many types of animals eat grass as their main source of food. These animals are usually called "herbivores", although certain herbivores are more inclined to eat leafy plants, and some omnivorous or even primarily carnivorous animals have been observed eating grass on occasion. Some of the most familiar grass eaters include cows, sheep, horses and rabbits.

Some people have allergies to grass.

Grasses play an important role in agriculture

In sports

The yellow area is the pitch currently in use. Parallel to it are other pitches in various states of preparation which could be used in other matches.

Grass is also used in several contexts in sports, most notably with sports played on fields such as football, American football, cricket, baseball, and rugby. In some sports facilities, including indoor domes and places where maintenance of a grass field would be difficult, grass may be replaced with artificial turf, a synthetic grass-like substitute. Sports such as cricket, golf and tennis are particularly dependent on the quality of the grass on which the sport is played.

A cricket pitch often starts with a thin cover of green blades, but over the course of a five-day match tends to dry out and harden. Even in one-day matches cricket pitches are often nearly bare earth covered only by a layer of dry yellow stalks. A green or moist pitch favours the bowler, as it varies the bounce of the ball and increases its movement. A hard, dry pitch gives a more predictable, higher bounce which favours the batsman, at least initially. However, as the pitch dries out over a long match, it becomes somewhat better for fast bowlers, who benefit from unpredictable bounces caused by cracks that develop, and is especially favourable for spin bowlers, who can gain more deviation than normal with their deliveries because of the increased traction available on a dusty pitch. The nature of the outfield is also important, as grass may slow down a ball, causing it to stop before reaching a boundary or allowing a fielder more time to gather the ball. Laws 10 and 11 of cricket detail maintenance and protection of the pitch. Unlike test cricket, One Day International and indoor cricket which is played on an artificial surface.

In tennis, grass is grown on very hard-packed soil, and bounces may vary depending on the grass's health, how recently it has been mowed, and the wear and tear of recent play. The most famous grass tennis court in the world is Centre Court at Wimbledon. But tennis is usually played on clay courts, and only a few regular tennis tournaments are played on grass. The surface is softer than hard courts, so the ball bounces lower, and players must reach the ball faster. Grass courts are now rare as they must be watered and mowed often, and take longer to dry after rain than hard courts.

Golf, on the other hand, is usually played on grass, and is dependent on the maintenance of a very large area of well-cut grass. Grass on golf courses is kept in three distinct conditions: that of the rough, the fairway, and the putting green. Grass on the fairway is short and even, allowing the player to cleanly strike the ball. Playing from the rough is a disadvantage because the grass is generally much longer, which may affect the flight of the ball. Grass on the putting green is the shortest and most even, ideally allowing the ball to slide smoothly over the surface. An entire industry revolves around the development and marketing of grasses for golf courses.

In fiction

Grass plays a central role in two important science fiction catastrophe novels from the 1940s and 1950s, Ward Moore's Greener Than You Think, in which the world is slowly taken over by unstoppable Bermuda Grass, John Christopher's The Death of Grass, in which a plague that kills off all forms of grass threatens the survival of the human species.

Gallery

• 
  A sea of neatly cut grass surrounds the bunkers at Filton Golf Club, Bristol.
• 
  Tall grass growing wild at Lyme Park
• 
  In some places, even small areas of grass are valuable. These steps were built to access grass for animal feed. Swiss-Italian region near Bignasco.

References

• Chapman, G.P. and W.E. Peat. 1992. An Introduction to the Grasses. CAB Internat., Oxon, UK.
• Cheplick, G.P. 1998. Population Biology of Grasses. Cambridge University Press, Cambridge.
• Milne, L. and M. Milne. 1967. Living Plants of the World. Chaticleer Press, N.Y.
• Soderstrom, T.R., K.W. Hilu, C.S. Campbell, and M.E. Barkworth, eds. 1987. Grass Systematics and Evolution. Smithsonian Institution Press, Washington, D.C.
• Went, Frits W. 1963. The Plants. Time-Life Books, N.Y.

External links

• Why is the grass green?
• Need a Definition of Grass?
• Interactive Key to the Grasses of the Columbia Basin
• VEGETATIVE KEY TO GRASSES