Weekly “What is It?”: Sundews
There are few words better than pure delight to describe the face of someone who sees a sundew for the first time. Maybe it is their size—often no bigger around than a quarter—or the droll pinwheel shape, but sundews could easily fit into a fable about garden gnomes or fairies in the woods. These tiny plants hide in plant sight–so small and flush to the ground that you likely won’t see them unless you’re specifically looking. However, once hunting in the right conditions, you will probably see them everywhere.
Sundews (Drosera spp.) are small carnivorous plants found in the same bogs you will find pitcher plants. They thrive in moist, mucky soil and full sun. They are also carnivorous for the same reasons pitcher plants are—their wet, acidic habitats possess few soil nutrients, so they harvest insects instead. Sundews use a different method for trapping insects—their flat, radiating structure has wider lobes on the ends, which are covered with hairlike tentacles. These hairs secrete droplets of sticky sap visible at the tip of each hair. Small insects are attracted to the dewlike sap and get stuck. The hairs curl around the insect like a slow Venus flytrap, and plant enzymes break down the bug.
There are almost 200 species of sundews, not all with the flat growth pattern. The threadleaf sundew has an upright structure, while others may grow in a spherical shape at the water’s edge. While paddling Boiling Creek on Eglin Air Force base property a few years ago, our group saw dozens of this variety growing on the trunks of cypress and tupelo trees at eye-level from our kayaks. They were about 3-4” in diameter, much larger than the 1” ones we typically see in the bogs.
Tarkiln Bayou Preserve State Park, Weeks Bay National Estuarine Research Reserve, or any place you find pitcher plants are a great place to find sundews. You may have to get on your knees to see them, and move the grasses aside. Bring a hand lens to magnify the delicate details of the droplets of sap perched at the tip of tiny hairs.
Even the famous naturalist Charles Darwin was enthralled with sundews, conducting experiments and writing volumes about them. In an 1860 letter to his geologist friend Charles Lyell, Darwin stated that “at the present moment, I care more about Drosera than the origin of all the species in the world.” If you, too, are fascinated with carnivorous plants, check out these resources from UF IFAS Extension and the Botanical Society of America.