Barry Rice

- doing science on a terrestrial planet -

Arkham Pond: Profile of a South Carolina Wetland
(Bulletin of the A.C.P.S., 1993, 12:4, 4.)

The southeastern coastal plain of the U.S.A. is a botanical paradise. Regional floristic works bulge with accounts of rare and fascinating species, while carnivorous plant enthusiasts think of it as home to many Pinguicula, Drosera, Utricularia, nearly all the species of Sarracenia , and of course Dionaea . But most people are ignorant of how rare North American carnivorous plants have become in the wild. In my naiveté I once assumed that Sarracenia must colonize every Florida field and lurk in every Mississippi moist spot. But the realm of reality does not overlap with this fantasy. Over decades of intensive and continuing development, more than 95% of the U.S. wetlands have been drained for logging operations, agriculture, or housing. All that remains are isolated relic plots, and to find them you need detailed directions and good maps. To be reliable, location information must be relatively recent--more than a few years old, and you may find that your directions take you to a new tobacco field. Happily, the damage is not complete. There are still large pieces of land owned by the government that contain lovely populations of plants. But the number of plants, and the genetic diversity they contain, continues to dwindle.

The Gulf Coast contains the greatest diversity of carnivorous plants in the states. If you travel away from it towards the north, by the time you reach South Carolina you have wandered out of the ranges of many carnivorous plants. This is doubly true if you move inland. But a surprise hides 160 kilometers from the ocean, in Lexington County. If you happened to be driving along one of the quiet forested roads in the area, you might notice it momentarily dipping into a small hollow. Before the wending road takes you back into the hills you may glimpse Arkham Pond1--but blink and you'll miss it. Although small, Arkham Pond is popular with both wildlife and anglers. Locals may tell outsiders that they own it, but actually the pond is overseen by The Nature Conservancy (TNC). TNC is a privately owned nonprofit agency which protects ecologically valuable land by direct action--it purchases it or, preferably, enters legal contracts with the landowners who relinquish the right to develop the land in perpetuity in exchange for decreased property taxes. (This contract is binding, even if the land changes ownership.) If you look carefully, you may see tiny TNC logos hammered to a few trees--that is if the locals haven't taken them down again. It may seem strange that the locals harbor occasional resentment to TNC, especially since it works to preserve the beauty of the area. But many communities distrust and resent the presence of any outsiders, and it is a testament to TNC's community relations that it has been able to educate and overcome as much of this attitude as it has.

Arkham Pond is fed by a single stream on its south end, and is in turn drained by another leaving northbound. Other small streamlets percolating through the woods enter it on the east side and contribute a little more water. Although a few animal trails wind around the pond's perimeter, these are difficult to follow and often lead to deep mud, thorny brambles, or impassable tangles of poison ivy. These natural obstacles deter casual pilgrims--but determined crusaders that navigate through the vegetation and grow indifferent to the mud and occasional scratches are well rewarded by Arkham Pond's treasures. The pond is located in a coniferous forest built upon sandy soil. This situation produces the low-nutrient, acidic conditions essential for most carnivorous plant habitats. (Measurements I have taken at several locations indicate a pH of 5.1-5.3.) Deep spreading beds of Sphagnum coat the ground. The moss reproduces endlessly and even colonizes the surface of deep water, generating thick shuddering mats that mimic solid ground. Treading upon it, the unwary will be quickly pitched into the water. With this in mind, it is relieving to know that Arkham Pond is at the extreme edge of the American Alligator's range. While they may have lived in the pond in the past, it has probably been a long time since one has paddled its waters. Probably.

thumb The greatest beauty of Arkham Pond lies in its enormous population of Sarracenia flava . This species is very successful--it will be found nearly anywhere that supports Sarracenia (except in the northern habitats of S. purpurea subsp. purpurea ). The type of S. flava at Arkham Pond is called var. rugelii2. This variety is all green, with no red venation. The only red colouration on the plant (excluding the blush on developing pitchers) is an irregular bloodstain patch on the pitcher column immediately under the lid. S. flava var. rugelii almost always occurs as it does at Arkham Pond, that is in large pure populations. (The most extensive stands of S. flava I've seen anywhere are of var. rugelii.) In wetlands where other forms of S. flava thrive, such as var. ornata, var. atropurpurea, copper-lid, all-green, and others, S. flava var. rugelii rarely grows, even though the habitats are identical. Considering the attention paid to S. rubra, S. flava var. rugelii is possibly a good candidate for subspecies status.

Wade into the water and you'd find it deepens quickly, so no S. flava grow more than a few meters beyond the shoreline. Away from the pond the terrain rises rapidly and the drier ground is quickly dominated by a forest where the deep shade precludes carnivorous plant life. But in the transition zone between deep water and piney shade lies a flat shoreline. With plenty of sunlight, this is an ideal habitat for carnivorous plants. The S. flava grow so densely you would have to take care to avoid stepping on them. And indeed you move slowly, for not only are the plants beautiful, but the seemingly endless colonies of silent organ-pipe pitchers produce a scene of weirdly alien majesty that demands your respect. If you speak it is in hushed tones, but you and your companions are hesitant to break the silence. Most of your trip is spent quietly, simply looking at this wondrous display. It may take an hour to pick your way 100 meters through the plants, for every log and every streamlet delivers a new surprise. Over here a Sarracenia patriarch has multiplied into a horde of tall hungry traps, while elsewhere a throng of pitchers growing in water almost too deep for survival are all stiffly leaning to one side--apparently nearly toppled by some animal's blundering visit. It will not be until the next year's crop of pitchers that the evidence of the creature's passage will be forgotten. Moving along, perhaps a hummock of Sphagnum quartering a legion of enterprising seedlings catches your eye. They are colonizing a few square meters of sunny ground made available when a tree blew down in a storm. They are doomed, of course, as the pines will eventually reclaim that scrap of land as their own. While the pond first seemed static, becomes apparent it is constantly changing, a place of great activity.

Although it is the most dramatic, S. flava is not the only carnivorous plant at Arkham Pond. The areas with thick mats of Sphagnum, especially those lightly shaded by shrubs, are dotted with vigorous S. purpurea subsp. venosa. This species does very well in full sun, so I don't know why it hides in the bushes at Arkham. You can also find S. rubra. This species has, depending upon in which botanical camp you pitch your tent, up to five subspecies. Arkham Pond is in the confluence of the ranges of S. rubra subsp. rubra and the very rare S. rubra subsp. jonesii. Don Schnell has visited this site and told me he feels these plants may be intermediate between the subspecies. Unfortunately, not many are present and those few are having a difficult time--they are not thriving like the other two species growing with them. I have not found any Sarracenia hybrids at the pond.

Growing on the logs, in the moss, and on the sandy flats you can find many Drosera intermedia and D. capillaris. A very occasional D. rotundifolia finishes the list of sundews at Arkham. Everywhere are yellow flowers of Utricularia subulata--a weed in the wild and in many greenhouses. Finally, in the shallows intertwine bladder-bedecked strands of U. gibba and U. striata, the last entries on the list of carnivores at the pond.

Arkham Pond is rich with botanical wonders. With at least nine carnivores, terrestrial orchids (such as Pogonia ophioglossoides), and picturesque water-lilies such as Nymphaea odorata, the pond never fails to please. Whatever happens to land elsewhere, TNC has this pond protected. (Actually one of the main reasons TNC is interested in Arkham Pond is because it houses a rare Vaccinium.) As long as the stream remains unpolluted upriver, acid rains are kept at bay, and field collection prevented, this is one carnivorous plant site that will stay with us.

1)The name Arkham Pond is a contrivance. The pond's real name is not revealed to protect it from damage.

2)I wrote this article back when there was some confusion about the identities of "var. maxima" and "var. rugelii". I have slightly edited the presentation on this web page to make it consistent with current (post 2005) usage.


10 November 2007