Carnivorous Plants

In the month since our last blog post, we have been exploring the Coastal Plain from northern Florida to North Carolina. After recovering from Ghana, we had a couple of weeks to kill before starting a series of searches for new plant genera (otherwise, we might have been too early to see them flowering). We ended up traveling west from Jacksonville, through the Panhandle, staying at Suwanee River, Ochlockonee River, and Torreya State Parks (SP) for three or four nights each, then returning to the Atlantic side and staying at Gold Head Branch SP to start our searches. Our new air conditioner proved very useful during this stretch as almost every day was hot and humid. On May 5 we started making our way north, close to the coast, towards North Carolina.

We paddled as often as we could during the month, canoeing 8 times and covering 50 miles, mostly on rivers we had to first paddle upstream. On flat water we make a rate of about 3 mph, so if the current is 1.5 mph, a pretty typical number on these paddles, our speed upstream is only 1.5 mph, but we zoom back at 4.5 mph, in one-third the time. Fortunately, on St. Mary’s River, which forms part of the border between Florida and Georgia, we were able to arrange a shuttle and so were able to enjoy a longer downstream float.

We had quite a few encounters with Bachman’s Sparrows this spring, both seeing and hearing them well. The vocalizations of this species, long ago known by the more poetic name Pine Woods Sparrow, are unusual in that the sequential songs are usually on different pitches from one another, adding a very special quality to its performance. The only other North American species I know of that routinely does this is Hermit Thrush, which is considered by many (including me) to have the finest song of any bird on the continent. Other avian sightings we especially enjoyed were numerous Swallow-tailed and Mississippi Kites, Chuck-will’s-widows, Red-cockaded Woodpecker, and Prothonotary, Cape May, and Black-throated Blue Warblers.

We had some excellent botanizing during the month, finding a dozen new genera. Particularly good areas in Florida were St. Marks National Wildlife Refuge, where we had the lovely aquatic composite Scleroloepis uniflora (Pink Bog Buttons); Ochlockonee River SP, where we saw the rare Cleistesiopsis oricamporum (Coastal-Plain Rosebud Orchid); Apalachicola National Forest, where there were thousands of stunning pink Drosera tracyi (a tall sundew with thread-like leaves); and Angus Gholson Jr. Nature Park in Chatahoochee, where Silene catesbaei (Eastern Fringed Catchfly), known from only a dozen counties, was at the peak of flowering.

After paddling in Georgia and South Carolina, and finding Zenobia pulverulenta (Honeycup) in riotous bloom, with fragrant white sprays rising above its foliage, we continued north along the coast. As we entered North Carolina, we began contemplating what might be the single most exciting possibility of the year, the chance of seeing Venus’ Flytrap, Dionaea muscipula. Nearly all locations for this carnivorous plant are carefully guarded secrets, but the Green Swamp Preserve owned by The Nature Conservancy has a trail from which they are regularly seen.

As we neared the preserve, brimming with anticipation, we started seeing smoke, then flying ash. Pulling into the parking area, we found the preserve closed due to a wildfire. After some phone calls we found out that the fire, apparently started by lightning a few days earlier, was being pushed by winds right towards the preserve and the area was expected to be closed for a while. What a bummer!!

I did further research on locations for this species, and though a bit of a longshot, the most promising lead seemed to be back in South Carolina, so we backtracked for a day and explored a Carolina Bay. These interesting landforms occur on the Coastal Plain from northern Florida to southern New York, with a particular concentration in the Carolinas. In this region, the bays are oval depressions oriented approximately northwest to southeast, with slightly higher rims, which often take the form of sandy ridges, especially on the southeast ends. A variety of theories have been proposed regarding their origins, including some based on impact of meterorites or an exploding comet, but dating, sediment, and other geological data indicate extraterrestial origins are unlikely. Instead, the bays probably formed during the glacial periods, when frozen ground thawed and was sculpted by prevailing winds. Similar features are present in the high arctic.

Typically the rims of the Carolina Bays isolate the depressions so that their only water source is rain. They often fill with peat and become highly acidic because of leaching of the plant materials. The resulting habitat, often termed a bog if open and dominated by sphagnum moss, or a pocosin if impenetrably shrubby, has few available nutrients, and a limited number of plant species can grow under such conditions. Notable exceptions are members of the Rhododendron Family (Ericaceae), which are acid-tolerant, and carnivorous plants, which extract their nutrients from insects and aquatic micro-organisms they trap.

Despite a long day of searching along a pocosin edge, we had no luck and, not having enough time to wait out the wildfire, continued with our itinerary. Our next genus search took us to the coast, and after successfully finding our target in Carolina Beach SP, I drove to the end of the road to look for a turn-around. There Eileen noticed that there was a nature trail called the Flytrap Trail, which certainly warranted further investigation. I’m not sure why this site did not pop up in my internet searches, but the sign at the entrance confirmed their presence. The trail is under surveillance to deter unscrupulous collectors from poaching these plants. From an observation platform situated within a small sphagnum bog, we were able to spot about twenty flytraps, one of which had a flowering stalk with several buds!! We were thrilled and relieved to finally see this extraordinary species. Most of the plants were small, with basal rosettes about an inch across, though a few were up to twice that size.

Amazingly, from that platform, we were able to see all five of the well-known carnivorous plant genera in North America north of Mexico: Dionaea (flytrap), Drosera (sundews), Sarracenia (pitcher plants), Pinguicula (butterworts), and Utricularia (bladderworts)! Recently, another genus, Triantha, has been inferred to be carnivorous based on isotopic studies; its extremely sticky hairs apparently trap minute insects. We have seen that species, T. glutinosa (Sticky False Asphodel), in four Canadian provinces. Sundews and butterworts also capture insects via sticky hairs. Pitcher plants have downward-pointing hairs in their pitchers (modified leaves), which prevent insects that have walked in from walking back out. Bladderworts have small sacs that are suspended in water or wet soil, and trap aquatic organisms. When prey is detected, a trap door opens, sucking water into the lower pressure of the bladder, and then closes, in as little as a hundreth of a second! Flytraps close their traps, which are modified leaves, in about a tenth of a second when they sense motion twice in succession.

We got a takeout seafood dinner to celebrate and continued searching out obscure plant genera over the following days. While tracking down one of these in a pine savanna, I entered an extremely shallow but damp depression. Though focused on the target genus, I suddenly realized that the flowering stalks with buds I was seeing were flytraps, and they were everywhere! While still in shock, I walked a few more feet and found one flytrap that was three to four times the size of the largest we found previously! Once Eileen and I had spent several hours exploring the area, we concluded that there were a few hundred flytraps, several of which had fully open, green-striped flowers. In addition, there were dozens of individuals of rare orchid and pitcher plant species.

The effect of the hydrology on the plant life here was interesting, too. Going into the depression from one direction, there was an elevation change of perhaps 12 – 18 inches over a distance of about 15 feet, but the plant communities were completely different, with dry sand species at the top, and wet bog species at the bottom. One uncommon plant we saw occurred only on the gentle slope, where the moisture content was intermediate. It will not surprise us if the completely unexpected discovery of this site ranks as our top experience on our road trip this year. Fortunately, we still had some seafood leftovers, and so our celebration was able to span the entire remarkable flytrap experience!