Flowering plant

Flowering plants are amazing plants that grow beautiful flowers and create fruits. They are part of a group called Angiospermae. The word "angiosperm" comes from old Greek. It means their tiny seeds are kept safe inside a fruit. These plants are different from another group called gymnosperms.

There are more flowering plants than any other kind of land plant. They include plants without woody stems, grasses, most trees and shrubs, and many water plants. Flowering plants have special parts like flowers and a kind of tissue called xylem that helps them grow. They began to appear more than 300 million years ago and became very common during a time called the Cretaceous.

We depend on flowering plants for almost all our food. Crops like rice, maize, and wheat give us many of our calories. These plants also give us wood, paper, cotton, and ingredients for drinks and medicine. People grow flowering plants to make their homes and gardens beautiful, and flowers often have special meanings in different cultures. However, many flowering plants are in danger because of changes to their homes and the world's changing climate.

Distinguishing features

Angiosperms are plants that grow on land. They have roots, stems, leaves, and seeds like other seed plants. The special thing about them is that their seeds are inside a fruit. This is different from other seed plants, whose seeds are not protected like this.

Diversity

Ecological diversity

Further information: Plant ecology

The largest flowering plants are Eucalyptus gum trees of Australia and Shorea faguetiana trees of Southeast Asia, both reaching almost 100 metres tall. The smallest are Wolffia duckweeds, which float on freshwater and are each less than 2 millimetres across.

Most flowering plants use sunlight to make their own food. A few get their food from other plants or fungi.

Flowering plants live almost everywhere—on land, in fresh water, and even in the sea. On land, they grow in many places except very cold areas covered in moss and lichen, or forests with only coniferous trees. Some flowering plants grow in very acidic or alkaline places, like bogs or limestone areas.

Flowering plants come in many shapes and sizes. Some are small soft plants that live for just one or two years, while others are large trees that can live for centuries. Some even climb on other plants to grow tall.

Taxonomic diversity

There are estimated to be between 250,000 and 400,000 species of flowering plants.

The flowering plants are grouped into different families. Most flowering plant species belong to three main groups: eudicots, monocots, and magnoliids.

Evolution

History of classification

Main article: Plant taxonomy

The word "angiosperm" means "vessel" and "seed". It was first used in 1690 for plants with seeds inside special cases. Later, it came to mean all plants with enclosed seeds. By 1851, it meant all flowering plants.

Since 1998, scientists called the Angiosperm Phylogeny Group have updated how we classify flowering plants. They describe this group as a collection of related plants.

Coevolution with pollinators

Further information: Entomophily and Ornithophily

Flowering plants are successful because they have special relationships with animals that help them reproduce. Unlike some plants that use wind to carry pollen, flowering plants attract insects, birds, and bats with nectar, bright colors, and special scents. These traits often match the shape and senses of the animals that visit the flowers. For example, tube-shaped flowers fit well with long-tongued insects or hummingbirds. This helps plants reproduce better and has led to many different kinds of flowering plants.

Phylogeny

External

In 2019, scientists studied the family tree of plants and placed flowering plants in their evolutionary history.

Internal

The main groups of living flowering plants were studied in 2024 using genes from many plant samples. This helped confirm how these plants are related.

Fossil history

Main article: Fossil history of flowering plants

Fossils show that land plants have existed for at least 475 million years. Flowering plants appear suddenly in the fossil record about 130 million years ago. Most scientists think they evolved from other plants around 365 million years ago. By the end of the time called the Cretaceous period, about 66 million years ago, flowering plants had become common and replaced some other plants like ferns and conifers. Some fossils show that beetles were already living together with flowering plants by this time.

Reproduction

Flowers

Main articles: Flower and Plant reproductive morphology

Flowers are special parts of flowering plants that help them make new plants. They help make seeds and fruits. Flowers can grow at the end of a stem or from the side of a leaf. The part of the plant with flowers is usually different from the part with leaves.

Flowers have two main jobs. They make tiny cells called microspores, which become pollen, the male part. They also make larger cells called megaspores, which become the egg, the female part. These egg cells are inside a tiny part called the ovule, which is inside another part called the carpel.

Some flowers, like those on willow trees, only have a few parts and are pollinated by wind. Other flowers, like those on many plants you see, have extra parts to attract insects or birds. These extra parts include sepals, which are usually green and protect the flower, and petals, which are often colorful and can have scents or nectar to attract helpers.

Fertilisation and embryogenesis

Main articles: Fertilisation and Plant embryogenesis

When pollen from a flower lands on the part of another flower called the stigma, it starts to grow a tube. Inside this tube are two tiny cells. One of these cells joins with the egg cell to make a new plant embryo. The other cell joins with two other cells to make a special food for the embryo. The embryo grows, and the part of the flower that holds the egg turns into a fruit, while each egg becomes a seed.

Fruit and seed

Main articles: Fruit and Seed

As the embryo and its food grow, the walls around them change and combine to form the seed coat. The part of the flower that holds the eggs also changes to form the fruit. Sometimes, other parts of the flower help make the fruit, like in an apple where the flesh comes from part of the flower.

Some plants can make seeds without joining with another plant’s pollen. This is called apomixis and happens naturally in a small number of flowering plant groups.

Adaptive function of flowers

Charles Darwin wrote that mixing genes from different plants, called cross-fertilisation, is usually helpful for plants, while using genes from the same plant, called self-fertilisation, can be harmful. Flowers help plants mix genes from different plants, which keeps their genes healthy. This mixing helps plants stay strong and healthy over many generations.

Human uses

Main article: Human uses of plants

Flowering plants are very important for people. They give us most of our food, like wheat, rice, and maize. They also give us materials such as wood, paper, and fibers like cotton.

Flowers and plants are used in art, stories, and traditions. They appear in poems and paintings. Sadly, many plant species are in danger because of things like losing their homes or climate change. People work hard to protect these plants.