Plants, like animals, are made from cells and tissues. Plants have organs, too, but they’re quite a bit different from humans’. Most plants have two organ systems. One consists of its underground roots, and the other consists of above-ground shoots (stems, leaves, flowers, and seeds).
The roots bring in nutrients and anchor the plant to the ground. The stem is like the plant’s spine, supporting it above-ground and serving as a highway for nutrients and water between roots and leaves. The leaves collect energy from the sun and host the processes that make food for the plant through photosynthesis.
Scientists usually put plants in one of four major groups based on the types of tissues they have and how they reproduce. Plants fall under the Linnaean taxonomic system, too.
- Angiosperms are flowering plants. These plants have vascular tissue (tissue that transports fluid and nutrients internally, which is similar to human veins) and produce flowers and seeds. Angiosperms include roses and all the flowers in your garden, palm trees, and apple trees.
- Bryophytes are plants that don’t have a vascular system and don’t produce flowers or seeds. They reproduce by releasing spores. Lichen, liverwort, and many types of mosses are bryophytes.
- Ferns are plants with vascular tissue, but they don’t produce seeds.
- Gymnosperms are plants that produce cones and seeds rather than flowers, and they have vascular tissue, too. Your Christmas tree is a gymnosperm, as are California’s giant sequoias and most non-flowering shrubs.