Poaceae

Grass is a very big plant family.

It grows in many places. Some grass is in your yard.

Many people eat grass food like rice and corn.

Even animals like kangaroos eat it. Grass can grow back fast after it is cut. This is because the part that makes new growth is near the bottom. This helps the plant stay safe when animals eat it. Grass is a very important part of our world.

Grasses are a huge family of plants.

They are found on every continent. Some even grow in Antarctica! There are about 12,000 different species. This makes them the fifth-largest plant family on Earth.

Grasses are very important for people. We eat many of them every day. Rice gives people 20% of their food power. Wheat provides 19%. Maize, or corn, gives 5%. We also use bamboo and straw for building. Some grasses can even make biofuel.

Grasses have special parts. Their stems are called culms. Most culms are hollow. The leaves grow from the bottom. This helps the plant survive when animals eat it. This part is called the meristem. It lets the grass grow back fast after grazing.

Many animals, like kangaroos, eat grass to live. Large areas of the Earth are covered in grass. These places are called grasslands. They cover about 31% of the land. Grasses can live in many places, like forests and deserts.

Grasses are a huge and important group of plants.

Scientists call this family Poaceae. It is the fifth-largest plant family on Earth. There are about 780 different genera and 12,000 species. You can find them on every continent. Some even grow in the cold parts of Antarctica.

These plants are found in many places. They grow in wetlands, forests, and even the tundra. Large areas of land are covered by grasses. These places are called grasslands. They cover about 40.5% of the Earth's land.

Grasses have a very clever way of growing. Most grasses have stems called culms. These stems are usually hollow tubes. The leaves grow from the very bottom of the plant. This is a special way to grow. It helps the plant survive when animals eat it. This part is called the meristem. Because the growth happens at the base, the grass can grow back quickly.

This helps them survive being mown or grazed. Some leaves even have tiny bits of silica to stop animals from eating them.

Many people depend on these plants to live.

We grow cereal crops like wheat, rice, and maize. These foods give humans a lot of energy. Rice provides 20% of all dietary energy for people. Wheat provides 19% and maize provides 5%. We also use bamboo and straw for building. Some grasses can even be turned into biofuel. This is a type of fuel made from plants. Animals like cattle, horses, and rabbits also eat grass to live.

We have learned a lot about grasses over time.

The name Poaceae was given by John Hendley Barnhart in 1895. The name comes from an Ancient Greek word for fodder. Scientists have found very old grass fossils. Some fossils from China are 113 to 100 million years old. These are the oldest known grass fossils. Other fossils were found in dinosaur dung in India. These fossils show that grasses have been around for a very long time.

Grasses come in many different types.

Some are annuals that live for one year. Others are perennials that live for many years. There are also C3 and C4 grasses. C4 grasses are better at using water in hot places. About 46% of all grass species are C4 plants. You might know bamboo, which is a type of grass. You might also know the grass on your lawn. All these different plants belong to the same big family.

Poaceae is a massive and essential family of flowering plants.

These plants are commonly known as true grasses. They belong to a group called monocots. This family includes many things we see every day. You might recognize cereal crops, bamboo, or the grass in a lawn. It is the fifth-largest plant family on Earth. It follows the Asteraceae, Orchidaceae, Fabaceae, and Rubiaceae families in size. With about 780 genera and 12,000 species, Poaceae is nearly everywhere.

The physical structure of a grass plant is quite unique. Most grasses have stems called culms. These culms are usually cylindrical and hollow. They are plugged at the nodes, which are the joints where leaves attach. The leaves are arranged in two ranks and are often alternate. Each leaf has a lower part called a sheath that wraps around the stem. At the junction of the sheath and the blade, there is a small part called a ligule. This membrane or fringe of hairs prevents water or insects from getting into the sheath.

Grasses have evolved a very clever way to grow. Most plants grow from their tips, but grasses grow from the base. This low growth point is called the meristem. Because the growth happens near the ground, the plant can survive being eaten. This allows grasses to cope with frequent grazing by animals or mowing by humans. To protect themselves further, many blades are hardened with silica phytoliths. These tiny particles of silica can discourage animals from eating them. Some species, like sword grass, are even sharp enough to cut human skin.

The reproductive parts of Poaceae are also very specific. Flowers are arranged in structures called spikelets. These spikelets can be grouped into larger shapes called panicles or spikes. A single spikelet contains one or more florets. Each floret has an outer bract called a lemma and an inner bract called a palea. The flowers are usually hermaphroditic, meaning they have both male and female parts. Most grasses are anemophilous, which means they are pollinated by the wind. The fruit produced is a caryopsis, where the seed coat is fused to the fruit wall.

Scientists classify grasses by how they handle sunlight and water. They use terms like C3 and C4 to describe their photosynthetic pathways. C3 grasses are often called "cool-season" grasses. Examples include wheat, rye, and oats. C4 grasses are called "warm-season" grasses. They have a special leaf anatomy called Kranz anatomy. This allows them to use water more efficiently in hot, dry places. About 46 percent of all grass species are C4 plants. This includes maize, sorghum, and sugarcane.

The history of grasses is written in the earth itself. The name Poaceae was given by John Hendley Barnhart in 1895. The name comes from the Ancient Greek word "póa," meaning fodder. We know grasses are very old thanks to fossils. The oldest known grass fossils were found in China. These microfossils were extracted from the teeth of a dinosaur called Equijubus normani. They date back to about 113 to 100 million years ago. Other fossils have been found in dinosaur dung in India, showing grasses were present during the Cretaceous period.

Poaceae is incredibly important to the global economy and ecology. These plants are the most economically important plant family. They provide a huge portion of the world's dietary energy. Rice provides 20 percent of all dietary energy for people. Wheat supplies 19 percent, and maize provides 5 percent. Beyond food, grasses provide building materials like bamboo and straw. They can even be turned into biofuel, such as ethanol from maize.

Finally, grasses shape the very landscapes of our planet. Grasslands, such as prairies and steppes, cover 31 percent of the Earth's land. When you include all grass-dominated areas, they cover about 40.5 percent of the land. This excludes Greenland and Antarctica. Grasses are the dominant vegetation in many habitats, including wetlands and tundras. They support many animals known as graminivores, which are animals that eat grass. This includes cattle, horses, rabbits, and even some insects like grasshoppers.