The southwest of Western Australia is home to many amazing and unique plants that have adapted to the nutrient poor soils of the region. One type of plant that has found a way to increase nutrient intake is the carnivorous sundews.
As you walk through the bush you may notice small plants with shiny droplets of sticky substance on them and these might be sundews. Sundews belong to the genus Drosera of the Droseraceae family and are one of the largest genera of carnivorous plants in the world. Australia has over 50 per cent of the world’s species, with Western Australia boasting over 200 individual species and subspecies, the majority of these being found in the southwest (https://florabase.dpaw.wa.gov.au/search/quick?q=Drosera).
Charles Darwin was so taken with Drosera that he wrote in one of his letters “…at the present moment, I care more about Drosera than the origin of all the species in the world…”.
Sundews have leaves covered with flexible hairs with a gland at the tip that exudes a sticky gelatinous substance known as mucilage. There are two types of glands, those that secrete a substance that attracts insects and those that secrete an enzyme to digest the insects. These hairs are able to move when they make contact with an insect and will bend towards the centre of the leaf to make sure that the insect remains trapped. This adaptation gives the plants a source of nitrogen which is essential to their survival and an element that is often lacking in the poor soils of the region. The flowers of Drosera are on long stalks that are distant from the sticky hairs of the plant and this is thought to be an adaptation so that potential pollinators are not trapped within the plant. The plants vary from prostrate rosettes like the one in the photo to climbing species like Drosera macrantha (Bridal Rainbow) or Drosera pallida (Pale Rainbow). So keep an eye out for these amazing plants next time you’re out walking in the bush.
 The Life and Letters of Charles Darwin, Volume II