Drosera or Sundew - Habitat and Distribution:
- Drosera, commonly known as Sundew, is a small, delicate insectivorous plant found in wet, marshy, and nutrient-poor soils. In India, different species of Drosera are distributed across varying habitats. Drosera peltata var. lunata grows extensively in the plains and hills up to an altitude of 3000 metres. Drosera burmanni is found primarily in eastern and central India, while Drosera indica typically appears along the western coast during the monsoon.
Morphological Features
- The Drosera species exhibit diverse leaf structures. They may have basal rosettes or radical and cauline leaves, depending on the species. For instance, indica has long, narrow leaves, D. burmanni features spathulate leaves, and D. peltata has peltate leaves. The upper surface of these leaves is covered in tentacle-like hairs that secrete a sticky fluid. These shimmering droplets resemble morning dew, earning the plant its common name—Sundew.
Insect Trapping Mechanism
- The tentacles on the leaves function as both attractants and traps. Insects are lured by the glistening drops and, upon landing, get stuck in the sticky secretion. Sensitive to proteins, the tentacles quickly bend over to enclose the insect. Digestive enzymes are then secreted by the glands on the leaf surface, breaking down the insect’s body. The nutrients released during digestion are absorbed by the leaf, and the tentacles remain closed until digestion is complete.
Medicinal and Economic Importance
- Apart from their ecological significance, Drosera species have traditional medicinal value. The leaves, rich in enzymes and organic acids, are used in folk remedies. Bruised leaves—sometimes mixed with salt—are applied to blisters, while indica leaf extract is used on corns. D. peltata is used by Ayurvedic practitioners in preparing ‘Swarna Bhasma’, a tonic believed to treat syphilis. Additionally, a pigment derived from D. peltata is used for dyeing silk.