Saturday, May 12, 2018
But, look, the morn, in russet mantle clad,
Walks o’er the dew of yon high eastward hill.
Shakespeare, Hamlet, Act 1, Scene 1
Dew is something that has long captured the imagination of the poets: It is born from the air, appearing as magic pearls in the morning, often forming spectacular, shiny scenery when the sun hits it just right. Then it disappears.
The little plant pictured here offers its own kind of “dew,” which of course is not real dew at all, and is not dependent upon the atmosphere. The plants each produce a cluster of tiny spoon-shaped leaves, these arranged in a low rosette. The whole plant may have a “spread” of only a couple of inches. It produces several white or pink-petaled flowers, arranged on an upright, threadlike stalk, 6-8 inches or so tall, growing from the center of the rosette.
Special hairs covering the upper surface of the leaves secrete a droplet of sticky, clear mucilage. In full sun, the little plants can be spectacular, producing a shimmering vision of sparkling diamonds, and when present in enough numbers the plants may form a brilliantly glistening carpet, very attractive … even if you are not on your hands and knees. This species and its relatives belong to a genus whose name in Greek means “glistening” … as in the morning dew.
The beauty of such a scene belies the potential danger to small insects and tiny critters, often attracted to the galaxy of tiny droplets. Some evidence indicates that the droplets have a tempting, sweet taste, hence even more attractive. Thus, tiny critters may be showing up for dinner. Once contacting the drops, though, these insects are invariably glued to the leaf, as the collective effect of the secretions forms a natural kind of sticky fly-paper.
Struggling against the sticky dew is of little help, and generally further enmires the victim. After a little while, the tiny leaf blade rolls over the trapped bug, and death soon follows. Well, after all, this is an insectivorous plant, and it is actually feeding upon the valuable nutrients present in the insect’s body. So it turns out that the little dinner guests showing up are they themselves on the menu.
This little plant is one of about 30 different species of insectivorous (or “carnivorous”) plants that can be found in the southeastern USA. This particular species is reasonably common on the coastal plain from Virginia to Texas, and it likes to grow on damp peat or sand of bogs or pond margins.
All insectivorous plants are fully capable of producing their own carbohydrates as a source of energy, through the process of photosynthesis. Additionally, though, insectivorous plants have all evolved mechanisms enabling them to variously trap tiny animals. Nutrients in the bodies of the trapped critters is ultimately absorbed by the plant, which thus capitalizes from this curiously derived “fertilizer.”
Ecologically, most insectivorous plants tend to be found on soils that have low pH, or relatively acidic. Nutrients in such places are generally harder for plants to absorb, so carnivory comes in very handy.
[Answer: “Pink sun-dew,” Drosera capillaris]
John Nelson is the curator of the A.C. Moore Herbarium at the University of South Carolina’s Department of Biological Sciences in Columbia, S.C. As a public service, the Herbarium offers free plant identifications. For more information, call 803-777-8196, visit www.herbarium.org or email email@example.com.