Common pepperweed facts for kids
Quick facts for kids Common pepperweed |
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| Scientific classification | |
| Genus: |
Lepidium
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| Species: |
densiflorum
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Lepidium densiflorum is a type of flowering plant in the mustard family. You might know it by its common names, common pepperweed or prairie peppergrass.
This plant is very common and can be found all over North America. It grows in many different places across Canada and the United States.
Contents
What Is Common Pepperweed?
Common pepperweed is usually an annual or biennial plant. This means it lives for one or two years. It grows a short, straight stem that can branch out. The stem can reach about 30 centimeters (about 12 inches) tall.
Its leaves start in a circle at the bottom, called a basal rosette. These leaves can be up to 10 centimeters (about 4 inches) long. Leaves higher up on the stem are smaller and have fewer lobes or divisions.
Flowers and Fruit
The plant produces groups of tiny flowers called racemes. Each flower has small sepals, which are like tiny leaves that protect the bud. They are only about a millimeter long. Usually, there are no petals on these flowers. Sometimes, you might see very tiny, undeveloped petals near the sepals.
After the flowers, the plant grows small, flat fruits. Each fruit is only a few millimeters long.
Where Does It Come From?
Scientists believe that Lepidium densiflorum is originally from North America. It was first found in Europe in the early 1900s, in Finland. Since then, it has spread a lot. It is now considered a common weed in many places.
What Does It Look Like Up Close?
Leaves and Stem
The leaves at the base of the plant form a rosette. They grow in a spiral pattern around the stem. These leaves have pointed tips and jagged edges. They are also deeply lobed, meaning they have rounded sections.
Leaves higher up on the stem are smaller. They have shorter stalks and sharper, saw-like edges. The very top leaves are long and thin, with few or no lobes. The stems and leaves can have tiny hairs.
Flowers
The flowers are very small, less than 1/8 of an inch across. They grow in dense clusters. As the plant grows fruit, these clusters get longer. The sepals are oval-shaped and about 1 mm long.
The petals are usually missing or very tiny. If they are there, they are only half the length of the sepals. The part of the flower that becomes the fruit, called the style, is very short.
Fruit
The fruit is a flat pod. It is shaped like an upside-down egg or a wide, upside-down egg. It is 2 to 3.5 mm long. The fruit has a small notch at the top and narrow wings along its edges.
Where Does It Grow?
Lepidium densiflorum likes sunny places that are not too wet. It grows well in rich, loamy soil. But it can also grow easily in rocky or sandy soil.
You can find it all over Ontario, Canada. It is a very common weed. It grows in farms, gardens, sandy areas, along roadsides, and in waste areas.
How Does It Grow?
This plant can be an annual or a biennial. Usually, its seeds sprout in the summer. They form a low cluster of leaves that stays through the winter. The plant then flowers the next year, sometimes until July.
What Is It Used For?
The seeds of Lepidium densiflorum have some interesting uses! They can help control mosquito larvae. This is a way to naturally reduce mosquito populations.
Also, special substances found in the seeds, like 4-HBITC and SNB, can help fight against things that cause damage to cells. This is called being "antioxidant." The plant also contains compounds called benzylic glucosinolates. These are important for how plants interact with diseases and can even be good for human health.
What Plants Look Similar?
Two plants that look similar to common pepperweed are Shepherd’s purse and Thlaspi arvense L., also known as Field Pennycress or Stinkweed.
How to Tell Common Pepperweed and Field Pennycress Apart
It can be tricky to tell these two plants apart, but here are some key differences:
- Stems: Field Pennycress stems have noticeable edges or corners. Common pepperweed stems are smooth and do not have these edges.
- Flowers: Field Pennycress flowers have four green sepals and four longer white petals. These petals are oblong-shaped and 2-4 mm long. Common pepperweed flowers usually have white petals that are shorter than the sepals, or sometimes no petals at all.
- Fruit: Field Pennycress fruits are almost round or inversely egg-shaped. They are much larger, 8-16 mm long, flat, and have wide wings all around with a deep notch at the top. Common pepperweed fruits are smaller, 2-3.5 mm long, and have a small notch at the top with narrow wings.
- Seeds: Both plants have fruits divided into two sections. Field Pennycress has 2-8 seeds in each section. Common pepperweed has only one seed in each section. This is often the best way to tell them apart!
