Angiosperms | Definition, Anatomy, and Examples
What are Angiosperms plants? An angiosperm is a flowering plant that produces seeds enclosed in an ovary. Angiosperm comes from the Greek words “Angio” which means a vessel, and “Sperma,” which means seed. They are three broad groups within the plant kingdom, the other two being gymnosperms and cryptogams. There are around 300–315 thousand species of angiosperms, representing about two-thirds of all flowering plants. They are evolved from a group of gymnosperms called Gnetales.
Angiosperms are closely related to gymnosperms. They are also evolved from some nonflowering seed plants, the cycads, and Ginkgo. They reproduce either by self-fertilization or cross-pollination. Their plants are dicots or monocots. The number of seeds produced by angiosperms ranges from one seed to over 2,000. Examples of Angiosperms are Corn (maize), Dandelion, Quaking Grass, roses, geraniums, and tulips.
Angiosperm plants range from tiny herbs to large trees, and they display a wide variety of flower shapes and colors. Angiosperms typically produce fruit with seeds, which people and other animals eat. Some plants can reproduce asexually through vegetative reproduction or apomixis. That is, they produce seeds without sexual fertilization.
Angiosperms have four primary organs: the root, the stem, the leaves, and the flower.
- The Root is the part of the plant that anchors it in the soil and absorbs water and minerals from the earth.
- The Stem is the plant’s direct support, and it is usually green with chlorophyll.
- A Leaf is the plant organ that captures sunlight for photosynthesis.
- The Flower is the reproductive organ of angiosperms; this is often where seed production occurs.
Angiosperm Flower Anatomy
An angiosperm flower contains four flower parts: sepals (which protect the inner organs during development), petals, stamens, and carpels.
- The Sepals are usually green or the same color as the petals. They enclose the flower in bud form.
- Petals come in various colors and shapes, and they attract pollinators to the plant’s reproductive organs during reproduction.
- Stamens produce pollen by producing sperm cells called gametes. There are usually more stamens than petals; one of the stamens is tiny and has two sperm cells.
- The Carpels produce ovules that contain female gametes called eggs. A single egg becomes a zygote (unit of two cells) after fertilization by sperm.
Angiosperms are a flowering plant found in the Asmatidae and liriodendron families. Angiosperms are distinguished from other plants by their flowers, which are the plant’s reproductive organs. Angiosperm flowers are typically characterized by their petals, sepals, and stamens. Angiosperms produce pollen by producing sperm cells called gametes. There are usually more stamens than petals in an angiosperm flower. Angiosperms are the most common type of plant in the world, and they can be found in almost every environment.
Angiosperms display a wide variety of flower shapes and colors. Petals often have markings or patterns that attract pollinating insects. Other petal features can also affect pollination, such as the hairs on petals in some species of “Protea.” A few Angiosperm species rely on smell to attract bees to pollinate them.
Reproduction in Angiosperms
Angiosperms reproduce in two ways: by self-pollination or cross-pollination.
Self-pollination occurs when the pollen from the stamen of one flower falls on the stigma of the same flower. This can happen if the flowers are close together or if there is a lot of rain and the pollen is washed around.
Cross-pollination occurs when the pollen from the stamen of one flower falls on the stigma of a different flower. This happens when the flowers are far apart, or the wind carries the pollen from one flower to another.
Fruits of this group can be fleshy or dry; they may contain one seed or many. Some common examples of angiosperm fruits are apples, oranges, and avocados.
An example of an angiosperm is the tulip, which belongs to the monocot group. Flowers fertilize internally; they produce male gametes (sperm) and female gamete (eggs), but the eggs are made within the ovules inside carpels instead of outside like in gymnosperms. The ovules are fertilized by the sperm cells when they contact them, and the zygote then develops into a seed.
One of the most well-known groups are corn or maize. Corn is a monocot, and the flowers fertilize externally. The ovules are located on the surface of the cob, and the kernels are the seeds that develop from the ovules. Corn is wind-pollinated, and the tassels at the top of the plant produce the pollen. The silks that grow out of the cob are sticky, and they catch the pollen as it falls from the tassels.
Dandelions are a type of weed found in many parts of the world. They are a typical example of an angiosperm that reproduces by self-pollination. The flowers are hermaphroditic, meaning they have both male and female reproductive organs. Dandelions can cross-pollinate with other dandelions, but usually, the flowers fertilize themselves. Dandelions have a deep root system, and they can spread quickly. The flowers are open for only a short time, and they produce a lot of pollen. This makes it easy for the flowers to pollinate themselves.
Oak trees are an example of an angiosperm that reproduces by cross-pollination. For an oak tree to produce acorns, the flowers must cross-pollinate with other oak trees. This is because oaks have male and female flowers on separate trees. The wind carries the pollen from one tree to another.
Difference between Angiosperm and Gymnosperms
Gymnosperms and Angiosperms’ fundamental characteristics are described below:
- The most significant difference between angiosperms and gymnosperms is how they reproduce.
- Angiosperms produce flowers and bear fruit with seeds, whereas gymnosperms do not produce flowers or fruit.
- Gymnosperm means “naked seed,” which refers to how their seeds are exposed rather than enclosed by fruits in angiosperms.
- Another difference is that gymnosperm seeds have only one cotyledon, or seed leaf, while angiosperm seeds have two or more.