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Ch.8. Plants. Section 2: Plants Without Seeds. Nonvascular Plants There are three major groups of nonvascular plants: mosses, liverworts, and hornworts. These low-growing plants live in moist areas where they can absorb water and other nutrients directly from their environment. Mosses
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Ch.8 Plants
Section 2: Plants Without Seeds • Nonvascular Plants • There are three major groups of nonvascular plants: mosses, liverworts, and hornworts. These low-growing plants live in moist areas where they can absorb water and other nutrients directly from their environment. • Mosses • There are more than 10,000 species, mosses are the most diverse group of nonvascular plants • Thin, rootlike structures called rhizoids anchor the moss and absorb water and nutrients from the soil
Section 2: Plants Without Seeds • Nonvascular Plants • Liverworts • There are more than 8,000 species of liverworts • Liverworts are often found growing as a thick crust on moist rocks or soil along the sides of a stream • This group of plants is named for the shape of the plants leaflike gametophyte, which looks somewhat like a human liver • Liverworts have sporophytes that are too small to see • Hornworts • There are fewer than 100 species • Hornworts live in moist soil, often mixed in with grass plants • They are named for the slender, curved structures that grow out of the gametophytes
Section 2: Plants Without Seeds • Seedless Vascular Plants • Ferns, club mosses, and horsetails have true vascular tissue, and they do not produce seeds. Instead of seeds, these plants reproduce by releasing spores • Unlike mosses, seedless vascular plants can grow tall because their vascular tissue provides an effective way of transporting materials • Have strong cell walls, with strength and stability • Grow in moist surroundings • Plants release spores into their surroundings, where they grow into gametophytes • When the gametophytes produce egg and sperm cells, there must be enough water available for fertilization
Section 2: Plants Without Seeds • Seedless Vascular Plants • Ferns • More than 12,000 species • Have true stems, roots, and leaves • Stems are underground • Leaves grow upward • Roots anchor the fern to the ground and absorb water and nutrients from the soil • Leaves or fronds, are divided into many smaller parts that look like small leaves • Wind/water carry the spores where they land and develop into a gametophyte
Section 2: Plants Without Seeds • Seedless Vascular Plants • Horsetails • Stems are joined containing silica, a gritty substance also found in sand • Have long, coarse, needle-like branches that grow in a circle around each joint • Small leaves grow flat against the stem just above each joint • Club Mosses • Have true stems, roots, and leaves with a similar life cycle • Only a few hundred exist today • Have vascular tissue, and grow in moist woodlands and near streams