Drosera

Sundews are very special plants.

They have leaves covered in tiny hairs. These hairs have sweet, sticky drops on them. These drops look like morning dew.

Small bugs are drawn to the sweet drops. When a bug touches them, it gets stuck. The plant then uses the bug for food. This helps the plant grow in poor soil. Some sundews can live for 50 years!

They are amazing plants to see.

Sundews are a large group of plants.

There are at least 194 different species. They live on every continent except Antarctica.

These plants are carnivores. This means they eat insects. They do this to get nutrients. Most plants get food from the soil. But sundew soil is often poor.

Sundews have leaves with tiny hairs. These hairs have sticky drops on them. These drops are called mucilage. They look like morning dew. Insects are drawn to the sweet drops. When they touch them, they get stuck. The plant then uses enzymes to digest the insect. Enzymes are parts that break things down. This turns the insect into a nutrient soup. The plant then absorbs this soup.

Some sundews can move very fast. When a bug touches a hair, it bends. This is called thigmonasty. It is a quick response to touch. Some leaves even curl around their prey.

Sundews also grow flowers. The flowers grow on long stems. This keeps them away from the sticky traps. This way, they do not eat the bugs that help them grow.

Sundews belong to a huge group of plants called Drosera.

There are at least 194 different species in this group. These plants live on every continent except for Antarctica.

They are known as carnivorous plants because they eat insects. Most plants get their food from the soil. However, sundews often grow in soil that lacks minerals. Eating insects helps them get the nutrients they need to survive.

These plants use a clever way to catch food. Their leaves are covered in tiny, stalked glands. These glands leak a sweet, sticky liquid called mucilage. This liquid looks like shiny drops of morning dew.

When an insect touches these drops, it gets stuck. The insect might die from exhaustion or because the goo blocks its breathing holes. After the insect is caught, the plant releases enzymes. These enzymes dissolve the insect into a nutrient soup. The plant then absorbs this soup through its leaf surfaces.

Many sundews can move to catch their prey. This movement is called thigmonasty, which is a response to touch.

When a tiny gnat touches a tentacle, the plant reacts. Some species have "snap-tentacles" that bend in just a few seconds. Other plants, like Drosera glanduligera, move in tenths of a second. Some species can even curl their whole leaf around the insect. This can happen in about 30 minutes for a plant called Drosera capensis. This movement helps the plant make as much contact with the food as possible.

Scientists have studied these amazing plants for a long time. Charles Darwin did much of the early research. He performed many experiments using a species called Drosera rotundifolia. His work was the first to prove that plants could be carnivores.

In a letter from 1860, Darwin said he cared more about sundews than almost anything else. The name "Drosera" comes from the Greek word for dewdrops. The common name "sundew" comes from a Latin phrase meaning "dew of the sun."

Sundews come in many different shapes and sizes. Some are tiny, like the pygmy sundews in Australia. Others can live for as long as 50 years.

They also grow beautiful flowers on long stems. These stems hold the flowers far above the sticky leaves. This helps the plant avoid eating the bugs that help it grow.

Most flowers are white or pink, but some Australian species are orange or red. The flowers often move to follow the sun across the sky.

The genus *Drosera*, commonly known as sundews, represents one of the largest groups of carnivorous plants.

Scientists have identified at least 194 different species within this genus. These plants are found on every continent except for Antarctica.

Sundews are specialized for nutrient uptake through carnivory. This behavior allows them to supplement their diet when they grow in soil that lacks essential minerals. Most species are perennial herbaceous plants. They often form upright or prostrate rosettes. Some climbing species, such as *Drosera erythrogyne*, can grow much longer stems. Remarkably, some sundews can reach a lifespan of 50 years.

The mechanism for capturing prey is a sophisticated biological process. The leaves are covered in glandular trichomes, which are tiny, hair-like structures. These structures include stalked glands that secrete a sweet, sticky substance called mucilage. This mucilage acts as a lure to attract insects.

When an insect touches the mucilage, it becomes ensnared. The prey may die from exhaustion or asphyxiation as the liquid clogs its spiracles, which are breathing holes.

Once the insect is trapped, the plant secretes various enzymes, including esterase, peroxidase, phosphatase, and protease. These enzymes dissolve the insect into a nutrient-rich mixture. This mixture is then absorbed through the leaf surfaces. Some species also use sessile glands, which are glands without stalks, to absorb this nutrient soup.

Sundews exhibit a remarkable movement known as thigmonasty. This is a rapid response to physical touch.

When a tentacle is stimulated, it fires action potentials that travel to the base of the tentacle. This triggers auxin-mediated acid growth. The plant hormone auxin causes protons to be pumped into the cell wall. This reduces the pH and makes the cell wall more acidic. The acidity relaxes a protein called expansin. This allows the cell to increase in volume through osmosis and turgor. As cells expand at different rates, the tentacles bend toward the center of the leaf. Some species, like *Drosera glanduligera*, can move in tenths of a second. Others, like *Drosera capensis*, can curl their entire leaf around prey within 30 minutes.

There are several distinct growth forms among sundews. Temperate sundews, found in North America, Europe, and Northern Asia, often form a hibernaculum. This is a tight cluster of unfurled leaves used during winter dormancy.

Subtropical sundews maintain growth all year due to stable climates. Pygmy sundews are a group of about 40 Australian species. They are characterized by miniature size and the formation of gemmae for asexual reproduction.

Tuberous sundews, including nearly 50 Australian species, form underground tubers to survive dry summers.

Finally, the *Drosera petiolaris* complex consists of tropical Australian species that live in warm, wet conditions.

The study of these plants has a rich history. Carl Linnaeus first published the genus in his work *Species Plantarum*. The name *Drosera* comes from the Greek word *drosos*, meaning dewdrops. This refers to the glistening mucilage that looks like morning dew.

Charles Darwin performed much of the early research on the genus. He conducted extensive experiments with *Drosera rotundifolia*. His work provided the first confirmation that plants could indeed be carnivorous. In an 1860 letter, Darwin expressed how deeply he cared about studying *Drosera*.

Sundews also produce specialized flowers to ensure successful reproduction. These flowers are typically held on long stems far above the carnivorous leaves.

This separation is an adaptation to prevent the plant from accidentally trapping its pollinators. The flowers are often radially symmetrical and possess five parts. Most flowers are white or pink, though Australian species can be orange, red, yellow, or violet. The flowers are often heliotropic, meaning they move to follow the sun's position in the sky. The ovary of the flower eventually develops into a seed capsule containing many tiny seeds.

While their leaves are highly developed for feeding, the root systems of most sundews are relatively simple. These roots are often weakly developed and serve primarily to anchor the plant and absorb water.

They are generally not used for significant nutrient uptake. However, some species use their roots for other purposes. For example, certain South African species use roots for food storage. Some Australian species use underground corms to survive dry seasons. In some cases, roots even assist in asexual propagation by sprouting new plantlets along their length.