Sundews or drosera are one of the largest genera of carnivorous plants. Drosera is a name derived from a Greek word "droseros," which means dewy. This aptly describes the appearance of the sundews, which have glistening drops of mucilage at the tip of each tentacle, looking like drops of morning dew. Sundews have various species and characteristics.
A Genus With Multiple Species
The Drosera genus includes 100 species. Among these, the pygmy sundews are differentiated by their short growth, thick hair growth in the crown centre meant to protect the plant from the hot summer sun and a formation of gemmae which is used for asexual reproduction. Subtropical sundews grow all year round while temperate sundews usually fall dormant during winter and tuberous sundews have underground tubers which help them survive blazingly hot summers typical of their habitat, Australia. Finally, Petiolaris complex is another species, which have a fine-tuned mechanism that helps them to adapt to their constantly warm but inconsistently wet habitat so as to compensate for dry periods.
Preference for Elevated Acidity Habitats
Sundews like seasonally moist or, on rare occasions, constantly wet habitats that have elevated levels of acidity and a lot of sunshine. Such places could be swamps, bogs, marshes and moist stream banks. Regions that favour the growth of sundews are the fybos of South Africa, the mountains of Venezuella and the Wallum country of coastal Australia. They also grow in New Zealand, North America and parts of Eurasia. Sundews have also managed to flourish in deserts, rainforests and shaded places as seen in the case of Queensland sundews.
Sundews have glandular tentacles, which have thick, sticky secretions at the top that cover their laminae. Sundews are carnivorous plants meaning that they feed on small prey, mostly insects. They trap and digest these animals by the help of two glands. Stalked glands secrete sweet mucilage to attract, trap and digest insects through the aid of enzymes. Sessile glands absorb the nutrients from the digested food. Small insects that touch secretions from the peduncular glands become ensnared. The more they struggle, the deeper they are enveloped by the mucilage until they die from exhaustion or asphyxiation.
The flowers of sundews are elevated far above the leaves through the aid of a long stem. This is so as to make the flowers more noticeable to pollinators. These flowers are very light-sensitive. They open in direct sunlight and follow the movement of the sun by facing the position of the sun in the sky. This adaptation is called heliotropism. The flowers usually have a white or pink colour. Some species, however, such as the Australian variety, have a more diverse colour range including yellow and orange.