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True Grasses


Brief Summary

    Poaceae: Brief Summary
    provided by wikipedia

    Poaceae (/poʊˈeɪsiaɪ/) or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses, commonly referred to collectively as grass. Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns and pasture. Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath. With around 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae.

    Grasslands such as savannah and prairie where grasses are dominant are estimated to constitute 40.5% of the land area of the Earth, excluding Greenland and Antarctica. Grasses are also an important part of the vegetation in many other habitats, including wetlands, forests and tundra. The Poaceae are the most economically important plant family, providing staple foods from domesticated cereal crops such as maize, wheat, rice, barley, and millet as well as forage, building materials (bamboo, thatch, straw) and fuel (ethanol).

    Though they are commonly called "grasses", seagrasses, rushes, and sedges fall outside this family. The rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of order Alismatales.

    Brief Summary
    provided by EOL authors
    There are over 9,000 species of grasses. These plants have leaves with blades on the end and spiky flowers. This family includes some of the plants that are most important to people. These include cereals, grains, lawn grass, and bamboo. Rice is best known for its small seeds, which are an important food all over the world.
    Brief Summary
    provided by EOL authors

    The true grasses, family Poaceae (formerly Gramineae), is one of the most speciose plant families, comprising over 10,000 species with a Gondwanan origin approximated at about 80-100 million years ago (although there are fossil specimens that potentially push the origin earlier; Prasad et al. 2011; Vicentini et al. 2008; Stevens 2013).

    Distributed world-wide, the true grasses are absent only in parts of Greenland and Antarctica, and are the most economically important group of monocots, as this family includes the true grains, pasture grasses, sugar cane, and bamboo.Species in this family have been domesticated for staple food crops (grains and sugar, for example), fodder for domesticated animals, biofuel, building materials, paper and ornamental landscaping, among other things.Grasslands cover at least 20% of the earth’s surface, although grasses also grow in biomes other than grasslands.

    Grasses are primarily wind pollinated, most have dangling anthers.They have hollow stems and grow from the plant base, rather than the tip, as an evolutionary response to predation.Many also protect themselves from predation by secreting silica crystals in their leaves.There are two main kinds of grasses, cool-season (C3) and warm-season (C4) grasses, which are distinct in their means for fixing Carbon.The evolution of C4 fixation has arisen independently in 4 of the 12 currently recognized grass subfamilies; a combination of changes in paleoclimate including temperature, aridness, seasonality are thought to select for new origins of C4 lineages (Vicentini et al. 2008).

    Genomic duplications are common in the true grasses, and thought to play important role in the evolution of the group as well as innovations leading to diversification of branches within Poaceae (for example, the evolution of flowers arranged as spikelets).

    (The Plant List 2010; Prasad et al. 2011; Stevens 2013; Vicentini et al. 2008; Wikipedia 2013)

Comprehensive Description

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