Sunday, June 14, 2009

Carnivorous Plants at Tolland Marsh Pond

Tolland Marsh Pond, May 31, 2009. Sarracenia flower at lower center.

Tolland Marsh Pond is a rather large (half a mile north to south) wetland, located in my neighborhood in the northeastern corner of Connecticut. The waters of the pond itself are acidic and dark, and ringed with a wide swampy margin of sedges, sphagnum moss, and thickets of blueberry and buttonbush. This is the kind of place where carnivorous plants grow, and in a recent trip to the pond I managed to find several different species of insect-eating greenery.

Sarracenia purpurea ssp. purpurea. Note mosquitoes in lower left pitcher; these may be Wyeomia smithii, a pitcher plant commensal.

The most impressive carnivorous plant native to New England is the Purple Pitcher Plant, Sarracenia purpurea. The pitcher plants were in full bloom when I checked them in late May. The dark maroon flowers attract pollinating bees, and are held well above the modified, water-filled leaves.

Sarracenia purpurea flower, about 2 inches across.

The leaves are the business end of the plant; the part that actually traps and kills insects, then breaks them down in order to obtain nitrogen and other nutrients that are in short supply in bogs. Unlike some carnivorous plants, Sarracenia purpurea does not move. Prey is attracted by the coloration of the leaf and nectar that it secretes. Unlucky critters slide into the pool of liquid inside, drown and are digested by bacterial action.

Pitcher plants and cranberries. The fruit must have come through the winter, but it was still edible, if a bit mushy.

At Tolland Marsh Pond, pitcher plants are present in a few open, boggy areas, but don’t seem to be tremendously abundant. I’ve seen a few dozen plants, but there are large areas of potential habitat that I haven’t checked.

Drosera rotundifolia. A few plants of this species are visible in the cranberry photo above, too.

Drosera intermedia favors wetter, muckier parts of the bog.

The pond is also home to both of the species of sundew that occur in inland Connecticut, Drosera rotundifolia and D. intermedia. Sundews have glandular tentacles on their leaves that secrete sticky mucilage, and trap small insects. The tentacles and leaves slowly fold around and digest their prey. Drosera rotundifolia grows all around the pond in sphagnum moss, or on half submerged waterlogged wood. Drosera intermedia isn’t as widespread, and I saw just a few patches of it in mucky peat in open areas on floating mats of moss and vegetation.

Tolland Marsh Pond: edge of the marshy parts of the area viewed through laurel thicket, White Oak and Red Maple. There is a pond out there, but you can't see it from here.

Tolland Marsh Pond isn’t easily accessible, which does have the beneficial effect of limiting the number of visitors to a fairly fragile habitat. There are a few informal trails around the pond, but my botanizing has involved a good deal of bushwhacking through laurel thicket (Mountain Laurel is pretty, but it is a slow and scratchy process to cross a dense stand of it). The marshes where the carnivorous plants occur are treacherous as well, with floating hummocks and sphagnum mats providing doubtful footing over sunless water and peat slurry of indeterminate depth. Tolland Marsh Pond also has Poison Sumac (Toxicodendron vernix), which is a bit like Poison Ivy, but twice as toxic and as tall as a lilac. Nasty, nasty stuff, which normal people will fortunately never run into, since it is almost entirely confined to bogs.

Tolland Marsh Pond, January 2009.

Sarracenia purpurea is evergreen, and although the leaves are low to the ground and can be hidden by even a little snow, the old seed heads are distinctive and fairly tall. So, winter is a good time to explore bogs for Purple Pitcher Plant populations. Places that are inaccessible in summer--too solid to be navigable by boat, but too unstable to negotiate safely on foot--can be reached by an easy walk after a long cold spell has frozen the landscape solid. And, there are no leaves on the Poison Sumac to worry about brushing up against.

Two Sarracenia purpurea flower stalks sticking above the snow (lower left and center).

I first found pitcher plants at Tolland Marsh Pond by taking advantage of good conditions for frozen bog walks this past winter. It would have been easier to find the plants if there hadn't been so much snow, but the old seed heads are fairly easy to spot, and seem to persist well into the cold season. There were even seeds still present in the capsules in January.

A little digging reveals the rest of the plant. Sarracenia purpurea leaves tend to turn solid red in winter, possibly to protect against light damage while the plants are dormant. The pitcher plants that I've seen in winter at Tolland Marsh Pond were close to open water in the center of the wetland, while the ones that I've been able to check on in summer were near solid land around the edge. In between, there is a stretch of possible habitat where I haven't looked. Time to think about another expedition!

Monday, June 1, 2009

Aloe dichotoma: the Quiver Tree

An Aloe dichotoma forest east of Ratelpoort, Northern Cape, South Africa (August, 2004).

In Namaqualand, in the arid northwestern corner of South Africa, about the closest thing to a forest that a traveler in search of shade will find are groves of Quiver Trees—Aloe dichotoma, or Kokerboom in Afrikaans—growing on rocky slopes. At about 10 to 20 feet high, Quiver Trees are giants of the succulent plant world, if on the small side by ordinary tree standards.

The forest of Aloe dichotoma in the photo is located near Ratelpoort in central Namaqualand, where some of the finest stands of this species that I have seen occur. Quiver Trees are widespread in the arid parts of southern Africa, growing naturally throughout much of the Northern Cape Province in the RSA, and north well into Namibia. There is quite a bit of variation in the form of the plants, and a short, highly branched form found in the northern part of the species’ range is sometimes recognized as a separate entity, Aloe ramosissima.

The common names Quiver Tree and Kokerboom both refer to the former usage of hollowed-out A. dichotoma stems as containers for arrows, by Khoisan people. Aloe dichotoma has been put to other ethnobotanical uses, as well. In the not too distant past in the hinterlands of South Africa, farmers without electricity would fashion A. dichotoma wood into boxes that served as crude refrigerators. The wood is very light and porous, and if kept wet by a drip of water a Kokerboom container apparently stays quite cool from evaporation. I actually saw a Kokerboom refrigerator outside of a farmhouse in Bushmanland, years ago, though the device had been idle for some time.

Aloe dichotoma seedling, about a foot high at four years of age.

The homeland of the Quiver Tree receives its rain in winter, for the most part, but cultivated A. dichotoma plants pretty much seem to grow whenever water is available. Ordinary cactus and succulent soil mixes and watering regimes seem to work well with the Kokerboom, though it is not nearly as tolerant of poor light as its houseplant cousin, Aloe vera. Seed is usually available from Silverhill Seeds, and can quickly yield nice little plants, especially if the seedlings are given plenty of root run. I started my seedlings in the autumn, though I wouldn’t be overly surprised if it was possible to germinate seed in other seasons.

Aloe dichotoma with Connecticut Yankee for scale. The landscape, with domes of red gneiss/granite, is typical of Namaqualand. This is the farm Namaras, southeast of Springbok (July, 2004).