Southern cutgrass facts for kids
Quick facts for kids Southern cutgrass |
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| Conservation status | |
| Scientific classification | |
| Genus: |
Leersia
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| Species: |
hexandra
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| Synonyms | |
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Synonyms
Asprella australis
Asprella brasiliensis Asprella hexandra Asprella mexicana Blepharochloa ciliata Homalocenchrus angustifolius Homalocenchrus gouinii Homalocenchrus hexandrus Hygroryza ciliata Leersia abyssinica Leersia aegyptiaca Leersia angustifolia Leersia australis Leersia brasiliensis Leersia capensis Leersia ciliaris Leersia ciliata Leersia compressa Leersia contracta Leersia dubia Leersia elongata Leersia ferox Leersia glaberrima Leersia gouinii Leersia gracilis Leersia griffithiana Leersia luzonensis Leersia mauritanica Leersia mauritiaca Leersia mexicana Leersia parviflora Oryza australis Oryza hexandra Oryza mexicana Pharus ciliatus Pseudoryza ciliata Zizania ciliata |
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Leersia hexandra is a type of grass known by several common names. You might hear it called southern cutgrass, clubhead cutgrass, or swamp rice grass. This plant grows all over the warm, tropical parts of the world. Sometimes, it is brought to new places and can spread very quickly, becoming an invasive plant. It can also be a weed in farms, especially in rice fields. However, it is also grown on purpose to feed farm animals like cattle.
Contents
About Southern Cutgrass
What Does It Look Like?
This grass is a perennial plant, meaning it lives for more than two years. It grows from special underground stems called rhizomes and creeping stems called stolons. These stems are hollow and lie on the ground, rooting easily wherever their joints (nodes) touch the soil.
From these creeping stems, upright shoots grow. They can reach more than a meter (about 3 feet) tall. Southern cutgrass often lives in water or very wet places. Its upright stems can even float on the water. These stems can grow very close together in wet areas, forming thick mats that look like "carpets" on the water.
The base of each leaf is covered in white hairs. The ligule, a small flap at the base of the leaf blade, can be stiff and dry, feeling like paper. The leaves themselves are long and pointed, growing up to 30 centimeters (about 12 inches) long. They can be flat or rolled up, especially at night or when they dry out.
The leaves are usually covered in very rough hairs, which makes them unpleasant to touch. They also have very sharp edges. The main vein in the middle of the leaf has spiny hairs that point backward, making it feel like a cutting edge. This is why it's called "cutgrass" – its leaves can actually cause painful cuts!
The flowers of this grass grow in a narrow or spreading cluster called a panicle, which can be up to 12 centimeters long. The panicle branches are covered with small, overlapping flower parts called spikelets. Each spikelet is about half a centimeter long. They can be green, purple, or sometimes have hints of orange or red.
White or purplish leaf-like structures called bracts surround the spikelets. These bracts have special comb-like hairs along their green veins. Each flower has six stamens, which are the parts that produce pollen. After the spikelets fall off, the panicle branches look like a zig-zag. This grass rarely produces fertile seeds. Instead, it usually spreads by growing new plants from its rhizomes or stem nodes. Large areas of this grass are often made up of identical plants, like clones.
This grass looks a lot like rice and other plants from the Oryza family. It belongs to the same plant group as rice, called Oryzeae. Sometimes, you can find it growing right in rice paddies.
Where Does It Grow?
Southern cutgrass loves shallow fresh water and wet, moist land. You can find it in places like marshes, swamps, ponds, and irrigation ditches. It also grows in flooded rice fields and on other wet farm lands and floodplains. It mostly grows in tropical areas, but it can also survive in some cooler temperate climates. It can even last for a while in drier conditions during a drought.
Animals and the Grass
This grass provides both food and shelter for many animals. Lots of water birds eat it. In Tanzania, it is a very common plant in the swamps where large birds like the shoebill (Balaeniceps rex) and the wattled crane (Bugeranus carunculatus) build their nests. In the Llanos region of Colombia and Venezuela, southern cutgrass is a very important food source for large groups of capybaras (Hydrochoerus hydrochaeris). It makes up almost a third of their diet!
The grass is also a host plant for the brown planthopper (Nilaparvata lugens). This insect can only complete its life cycle on southern cutgrass or cultivated rice. There are two types of this planthopper: one that prefers to lay eggs on rice, and another that prefers cutgrass. Even if they live in the same area, these two types usually don't breed with each other in the wild.
Is It a Problem Plant?
Southern cutgrass can be a weed in several crops, including tea, rubber, maize (corn), and sugarcane. However, it is a particularly big problem in rice fields. Since it is related to rice, it grows very well in the same conditions. Its thick "carpets" of vegetation can block irrigation waterways, which can lead to flooding and soil erosion.
This grass can also host many pests that harm rice plants. These include the brown planthopper, the green planthopper, the green rice leafhopper, and the rice gall midge. It can also host tiny worms called rice stem nematodes, which cause a rice disease called ufra disease.
Southern cutgrass can also catch many plant viruses that infect rice, such as rice grassy stunt virus and rice tungro virus. It can also get sick from bacteria and fungi like Xanthomonas oryzae, which causes leaf blight in rice, and Cochliobolus miyabeanus, which causes brown spot disease.
How Is It Used?
Even though its leaves are sharp, southern cutgrass is good for cattle to eat. It is kept as a pasture grass in swampy areas and is also cut to make hay for animal feed.
Cleaning Up Pollution
This plant has a very special ability: it is a hyperaccumulator of heavy metals. This means it can take up large amounts of metals like chromium, copper, and nickel from water and soil. Its ability to absorb chromium is especially amazing!
Because of this, southern cutgrass is being studied as a possible tool for phytoremediation. This is a process where plants are used to clean up soil and water that have been polluted by metals. For example, it could be used to clean up wastewater from factories that do electroplating, or to clean up polluted soil around such factories.
