A moss is a simple rootless plant with leaflike growths in a spiral around a stalk. Moss plants are held in place by rootlike filaments or threads made up only a few long cells called rhizoids. One type of liverwort is a simple, rootless plant that has a flattened, leaflike body. Liverworts get their name because, to some people, they look like a liver. The ending, -wort, means ?herb,? so the word liverwort means ?herb for the liver.? In liverworts rhizoid is made up of just one cell. Both mosses and liverworts grow in damp areas and range in size from 2 to 5 centimeters in height.

Of approximately 20 000 species of nonvascular plants, most are classified as mosses. H

In the life cycle of a fern, the gametophyte and sporophyte don?t depend on each other. Both forms of the fern plant can produce their own food. The fern plants that you may have seen growing in the woods are the sporophytes. A fern has leaves that grow above the ground from an underground stem called a rhizome. Roots grow from the rhizome to anchor the plant in the soil. The leaf of a fern is called a frond. Ferns produce spores in cases grouped together in structures called sori (sing., sorus) on the lower side of the mature fronds. The sori usually look like crusty rust, brown, or blackish-colored bumps. When a sorus opens, spores are released gradually as spore cases open. They land on damp soil or rocks and germinate into small, green, heart-shaped gametophyte plants. The gametophyte is called a prothallus. The prothallus produces sex cells that unite to form the zygote. The zygote develops into the embryo, then sporophyte, as in the mosses. But in ferns, the gametophyte also produces new rhizomes, which can grow into the separate sporophyte fern plants you are familiar with.

As Earth scientists have pieced together the geological history of Earth from clues left in rock layers, they have described a different climate during the Carboniferous period of the Paleozoic era, the tallest plants were species of ferns that grew much taller than any fern species alive today. Species of tree ferns found today in tropical areas may reach 3 to 5 meters. The climate was tropical over much of Earth, with steamy swamps covering large areas. When the tree ferns and other plants died, many of them became submerged in water and mud before they could decompose.

The largest group of seedless vascular plants is the division Pterophyta, which includes the ferns. There are 12 000 living species of ferns, but like the other divisions of vascular plants, additional species are known only as fossils.

When a volcano erupts, the lava covers the land and destroys the plants living there. After the lava cools, the spores of mosses and liverworts are carried to the new rocks by the wind and begin to grow wherever there is enough water. When they grow on rocks, their rhizoids can actually begin to penetrate tiny cracks in the rocks? surfaces. Weathering of rocks often begins when mosses release chemicals that begin to break down rocks. Organisms that are the first to grow in new or disturbed areas like these are called pioneer species. Pioneer plant species grow and die and begin to build up decaying plant material that provides nutrients for o

Some common words found in the essay are:
Life Cycle, Horsetails Horsetails, Liverworts Mosses, Nonvascular Plants, Mosses Club, Vascular Plants, Formation Fuel, Plants Seedless, Alternate Generations, Asexual Reproduction, vascular plants, club mosses, mosses liverworts, seedless vascular plants, life cycle, seedless vascular, vascular tissue, nonvascular plants, moss plants, sex cells, plants grow, mosses spike mosses, club mosses spike, simple rootless plant, plants bryophytes ferns,
Approximate Word count = 1716
Approximate Pages = 7 (250 words per page double spaced)