DK Science: Seed Plants
Most plants grow from seeds. These seed plants fall into two groups, angiosperms and gymnosperms. Angiosperms are the flowering plants. Their seeds develop inside a female reproductive part of the flower, called the ovary, which usually ripens into a protective FRUIT. Gymnosperms (conifers, Ginkgo, and cycads) do not have flowers or ovaries. Their seeds mature inside cones. Seeds may be carried away from the parent plant by wind, water, or animals.
Dandelion seeds have feathery parachutes to help them fly far from their parent plant. A dandelion flower is actually made up of many small flowers, called florets. Each develops a single fruit. The fruits form inside the closed-up seed head, after the yellow petals have withered away. When the weather is dry, the seed head opens, revealing a ball of parachutes. The slightest breeze lifts the parachutes into the air.
INSIDE A SEED
A seed is the first stage in the life cycle of a plant. Protected inside the tough seed coat, or testa, is the baby plant, called an embryo. Food, which fuels germination and growth, is either packed around the embryo or stored in special seed leaves, called cotyledons.
SPREADING WITHOUT SEEDS
Seeds are not the only means of reproduction. Some plants create offshoots of themselves – in the form of bulbs, tubers, corms, or rhizomes – that can grow into new plants. This type of reproduction is called vegetative reproduction. As only one parent plant is needed, the offspring is a clone of its parent.
A bulb is an underground bud with swollen leaf bases. Its food store allows flowers and leaves to grow quickly. New bulbs develop around the old one.
A tuber is a swollen stem or root with buds on its surface. When conditions are right, the tuber’s food store allows the buds to grow.
A corm is a swollen underground stem that provides energy for a growing bud. After the food in the old corm is used up, a new corm forms above it.
A rhizome is a horizontal stem that grows underground or on the surface. It divides and produces new buds and shoots along its branches.
GERMINATION OF A RUNNER BEAN
Most seeds require damp, warm conditions in order to sprout. During germination, the seed absorbs water and the embryo starts to use its food store. A young root, or radicle, begins to grow downward. Then a young shoot, or plumule, grows upward. This develops into the stem and produces leaves. The first leaves, called seed leaves or cotyledons, fuel the early growth until the plant’s true leaves appear.
A flower’s ovary usually develops into a fruit to protect the seeds and help disperse them. A fruit may be succulent (fleshy) or dry. Fruit is often tasty and colourful to attract fruit-eating animals. Its seeds can pass through an animal unharmed, falling to the ground in droppings. Seeds may also be dispersed on animals’ coats, by the wind, or by the fruit bursting open.
The seeds of dry fruits are dispersed in various ways. Peapods are dry fruits that split and shoot out their seeds by force. The hogweed fruit forms a papery wing around the seed, helping it to float on the breeze. The strawberry is a false fruit, but it is covered by tiny dry fruits, each with a seed.
Fleshy, brightly coloured, and often scented, succulent fruits are designed to attract the animals that eat and disperse them. Fleshy fruits such as apricots and cherries have a woody stone or pip that protects the seed. Called drupes, these fruits form from a single ovary. Many drupes, formed from many ovaries, may cluster to form a compound fruit, such as a raspberry.
Most plants grow from seeds. These seed plants fall into two groups, angiosperms and gymnosperms. Angiosperms are the flowering plants. Their seeds de
Examples of Non-Flowering Plants
Non-flowering plants are those that do not ever produce flowers. Some non-flowering plants, called gymnosperms, still produce seeds while others use spores for reproduction.
Gymnosperms are any type of vascular plant that reproduce via an exposed seed. While most flowering plants, known as angiosperms, have a seed enclosed in an ovary or fruit, gymnosperms (which means “naked seeds”) do not have covers on their seeds.
Some examples of non-flowering plants that are classified as gymnosperms include:
Found all over the world, conifers are largely woody plants, with trees making up the vast majority of conifers. They bear male and female cones that pollinate and spread.
Ancient plants dating to the Jurassic era, cycads are primarily found today in tropical or subtropical climates. Cycads are characterized by having thick trunks and large divided leaves; they have visual similarities to palms and tree-ferns.
Commonly known as the maidenhair tree, Gingko Biloba, is the only remaining species of the Ginkgophyta plant division. While they only grow in the wild in China, they have been cultivated around the world. They have green fan-shaped notched leaves that yellow in cooler weather. The male trees produce tiny cones that produce pollen; the females, once pollinated and fertilized, produce seeds with a noxious odor.
This plant division is fairly broad, including approximately 70 species, all of which have vessel elements transporting water within the plants. Examples of gentophyte non-flowering plants are Ephedra, Gentum and Welwitschia.
Other Non-Flowering Plants
Unlike Gymnosperms, all of these other non-flowering plants reproduce using spores; they do not produce seeds. Examples of some of the most commonly known non-flowering plants are ferns, mosses and liverworts.
Spores are tiny living cells which leave the plant on which they originate and are pollinated and fertilized away from the original organism.
Very common plants, ferns are vascular plants that have a stem, leaf and root. Ferns can be found in forests, but also are cultivated to improve the quality of soil or to improve air quality. They are also used ornamentally in landscaping as well as inside homes and some people even eat the plant. They produce spores which develop into a photosynthetic structure called a prothallus; the underside of the prothallus has organs that produce sperm and eggs that allow the ferns to self-fertilize, at which point a sporophyte develops and grows into a fern.
With approximately 12,000 species, mosses are very prevalent and grow in moist areas with low light.
Also known as Whisk Ferns, the Psilotales are a small group of plants, including Psilotum and Tmesipteris, believed to date from the Devonian era.
These small plants are like mosses but they have flattened bodies or stems and grow on rocks or the ground. Some even grow in pools of water. There are over 8,500 species worldwide, often in moist areas, though there are some outliers that live in drier climates.
Tropical mountains are the primary home of the club mosses, but they can be found in northern forests as well. These mosses are evergreens, with leaves that are needlelike and clustered.
Found in damp environments, hornworts are known to grow anywhere from the backs of trees to gardens and fields. They are small and short and are sometimes considered weeds. They were previously a part of the same grouping as mosses and liverworts.
Equisetum is the only genus of this non-flowering plant that is not extinct. With small leaves around the stem, these plants grow anywhere from 7 inches to 26 feet tall, depending on species.
These examples of non-flowering plants include those that reproduce with uncovered seeds and those that reproduce with spores. Learn more fun facts about plants by exploring plant adaptations in different environments.
Ready to learn more about non-flowering plants? These examples will help. View a helpful list, find out non-flowering plant names and get plant details.