Chapter 4 Classifying Plant Groups By Jenna Grabill
How Plants Are Classified Scientists have identified more than 260,000 kinds of plant. They think even more are to be discovered. 1,000,000 kinds of plants may exist that have not been found and named. Most of these plants live in the tropical rain forest. Scientists classify plants by putting them into smaller groups . They group them by body parts-seeds, tubes, roots, stems, and leaves. Main group of plants are seed plants, ferns, and mosses.
History of Classification Classification of plants started more than 2,000 years ago. The Greek philosopher Aristotle first classified plants and animals.
Vascular and Nonvascular Plants Seed plants and ferns are vascular plants. Tubelike cells Vascular means “vessel Have well developed leaves, stems, and roots. Moses are nonvascular Do not have tubelike cells. Short and must have constant contact with moisture.
Angiosperms Most species of plants are angiosperms, or flowering plats. The word angiosperm is made from the Greek word angeion. A capsule, or fruit , protects the seeds of angiosperms. The fruit forms form part of the flower. Flowers come in many shapes and colors.
Dicots and Monocots Angiosperms are divided into two kinds of plants, monocots and dicots. Most angiosperms are dicots. Dicots have two cotyledons inside the seed that contain food for the developing plant. Monocots only have on cotyledon.
Gymnosperms Nonflowering seed plants are called gymnosperms. Do not produce flowers.
Conifers and Other Gymnosperms There are over 700 species of gymnosperms. Major group of gymnosperms is conifers. Conifers are con-bearing gymnosperms.
Ferns The largest group of seedless vascular plants are ferns. There are over 10,000 species of ferns in the world.
Mosses Scientists have found over 9,000 species of mosses. Nonvascular plant. Leaf and steam like parts. Does not have well-developed roots, steams, and leaves. Must live in moist, shady places because they do not have vascular tissue to transport water.
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