Sunday, April 27, 2014

Carnivorous Plants in Okefenokee

When I signed up for the 2014 Wildflower Pilgrimage to the Okefenokee Swamp, I did it partly because I was interested in seeing pitcherplants, a type of carnivorous plant. I did not expect to see so many other types – including plants with cute names like butterworts, bladderworts, and sundews.

Do I look carnivorous? (Pinguicula lutea)
This is part 3 of my trip with the Georgia Botanical Society in late March 2014. You can read about part 1 and part 2 by clicking on the hot links.

Here is a bit of general information on carnivorous plants that I learned. First, the nutrition these plants get from insects is only part of their intake of nutrients. Second, these plants tend to grow in nutrient-poor soils that don’t provide enough nitrogen (such as in boggy places like swamps). Third, insects are trapped or gathered through the use of modified leaves, not with their flower.

Drosera capillaris  with flower stalk emerging
Tiny, sparkling red sundews (Drosera capillaris) grow on roadsides near the swamp. We saw them on several roadside field trips, nickel- to quarter-sized plants tucked in between other low-growing vegetation. We unwittingly tromped all over them in search of more showy flowering plants, but once we discovered them we were thoroughly charmed.

Snagged a bug?
In the types of carnivorous plants, sundews are known as “sticky flypaper” plants. The leaves contain both nectar and adhesive compounds to attract and retain prey. Digestive enzymes are there as well to process the catch. These plants do flower as well but we were too early for that.

We saw three kinds of butterwort on our roadside trips: the yellow butterwort (Pinguicula lutea) , the blue one (P. caerulea), and the dwarf one (P. pumila).

Pinguicula caerulea

The butterworts were all in flower and I did not realize at first that they were a type of carnivorous plant. The flowers were held high above the sticky leaves that formed a rosette on the ground.

Pinguicula foliage

As another type of sticky flypaper plant, the leaves are poised to capture small insects via tiny hairs which are covered in sticky mucilage. Once prey is caught, the leaf edge rolls inward to complete the process but never completely closes.

The terrestrial Utricularia subulata
We found bladderworts (a type of bladder trap) both on land and in the water. The tiny yellow Utricularia subulata was on the wet roadsides.  I can only imagine the tiny bugs that must be snagged by its bladder-like traps when the soil is saturated. I expect we would need a microscope to see them.

The aquatic bladderworts like Utricularia inflata were in the swamp and in the ditches, their bright yellow flowers like a flag on a ship (or at least on a bobbing life raft). The wheel-like arrangement of this bladderwort show some of the tiny bladder structures but there are more below. The bladders have tiny hairs attached to them that small creatures bump into. According to, “When they are stimulated, these hairs cause the flattened bladder to suddenly inflate, sucking in water and the passing animal and closing a trap door after it.”

Utricularia inflata

Finally we get to the pitcherplants (Sarracenia sp.) a type of carnivorous plants known as "pitfall traps." On land, we saw a few plants that were not yet flowering: parrot pitcherplant (S. psittacina ) and hooded pitcherplant (S. minor). Once we got into the swamp on a canoe, we were able to see the flowering yellow pitcherplant (S. flava). The flowers and tall pitchers were dramatically beautiful. The modified leaves that form the pitcher contain a bit of nectar to attract insects and then an illuminated funnel to trick the insect into thinking that going further into the funnel is the way out.

Sarracenia flava

Bottom line: plants are interesting. Like us, they have evolved over many years to adapt and thrive in the conditions that they have. Eating bugs to supplement their diet is just one of many ways. Cool stuff!