The Geological and Ecological History of the Okefenokee Swamp (part three)

Common and Interesting Plants Found in the Okefenokee Swamp

Most of the aquatic  plants that dominate the present day landscape of the Okefenokee Swamp were restricted to small scale marshes alongside the reduced number of rivers and streams that still incised the Okefenokee basin during the arid milleniums of the Ice Age when the water table fell and the swamp dried up between 36,000 BP and 7,000 BP.  The rest of the basin during this time period probably consisted of grassy pine savannah and scrub oak.  Nevertheless, these relic aquatic remnants provided the nucleus of the population that eventually re-established itself as the primary vegetation of the region.  Here are some interesting floral components of this environment.

Bald Cypress (Taxodium distichum)–Eight-hundred year old giants still stand in a few coastal swamps near Georgia’s coast.  One-hundred years ago, when loggers decimated much of these ancient bottomland forests, they skipped over the biggest cypress trees because they were too large and hollow, and therefore too much trouble to economically harvest.  One of these gigantic cypress trees is located in the Townsend Wildlife Management Area in McIntosh County.  It’s 44 feet in circumference.  Imagine 7 men, all at least 6 feet tall, laying end-to-end in a circle around the tree and they still wouldn’t completely encircle it.  It’s understandable but not generally known that cypress trees are relatives of the famous Californian redwoods.  They sure have great size and long life in common.

For more about Georgia’s big cypress trees see this following link  http://savannahnow.com/news/2010-08-30/700-year-old-cypress-tell-story-survival

I took this photo of a cypress tree in autumn foilage at Phinizy Swamp in Augusta, Georgia.  Unlike most coniferous trees, cypress trees lose their foilage in the winter, like deciduous broad-leafed trees.

Unlike most coniferous trees, cypress trees are not evergreen, and they shed their needles in the winter.  They usually live in flooded swamps. They have mysterious knees–wooden knobs that grow above water.  Scientists are uncertain whether these aid in respiration or simply balance the trees in the watery muck where they grow.

Water tupelo (Nyssa aquatica)–Cypress trees hollow out and provide roosting habitat for bats and homes for other animals, but tupelo trees become hollow more frequently.  Matt Clement, a grad student at UGA, found 97 roosts of Rafinesque’s bats along the Altamaha River, and most of them were in hollow tupelo trees.

Water shield or dollar pad (Brasenia schreberi), Floating Heart (Nymphoides sp.), and White Water Lilly (Nymphaea odorata)–These are three completely unrelated plants, but their leaves look similar.  In fact, I can’t really tell their leaves apart.  It’s an example of convergent evolution when different species evolve similar structures to solve the same ecological problems.  All three are what people think of as the lilly pads so commonly seen floating on the surface of the open water habitats in the Okefenokee Swamp that are often confusingly referred to as prairie because they’re treeless.  All three species have round floating leaves attached via long stems to underwater roots.

Panic grass (Panicum sp.) Saber-tooths and jaguars lurked hidden in patches of this tall cane-like grass, stalking the long-horned bison and horses that fed upon it during the Pleistocene.  The large fauna are gone but the flora remains.

Photo of some panic grass also known as maiden cane that I took at Phinzy Swamp, Augusta, Georgia.  There was another patch on the other side of the path that was 12 feet tall.  I wish I would’ve taken a photo of that.

Spanish Moss (Tillandsia usneoides)–Oddly enough, Spanish Moss is related to pineapple–both are Bromeliads or air plants.  Wind and birds spread seeds and fragments.  The seeds and fragments of the Spanish Moss lodge in other tree branches.  The Spanish Moss then grows (both from seed and vegetatively).  The plant survives by extracting nutrients from air and rain water, not from the trees upon which they land, thus they’re considered epiphytes, not parasites.  Birds, bats, spiders, and snakes live in and about the moss.

Spanish Moss hanging from either a water or laurel oak at Phinizy Swamp, Augusta, Georgia.  Spanish Moss is quite common in the lowlands of the Augusta area, but I’ve never seen any in hilly sections.

Bladderwort (Utricularia sp.)–Like strange creatures from a low budget horror film, carnivorous plants thrive in the Okefenokee Swamp.  Bladderwort is an underwater plant with no roots.  The bladder-shaped structure on the plant works like a trap door, a suction-on-contact action captures fish fry, mosquito larvae, tadpoles, and protozoa.

Pitcher plants (Sarracenia flava, Sarracenia mino, Sarracenia psittacaea)–There are three species of pitcher plants found in the Okefenokee–the hooded, the parrot, and the golden.  A sweet rotten odor emanating from the plants attracts insects which get trapped in tubular stems.  Backward hairs block insects from being able to escape, and eventually, they tire and fall into the toxic water at the bottom of the tube.  Bacteria in the water digests the insects, releasing nitrogen that the pitcher plant is able to absorb.

Round-leafed Sundew (Drosera rotundifolia)–The sticky hairs on this plant work just like flypaper, trapping hapless insects.

Burreed (Sparanium sp.)–Fossil mastodon dung discovered in the Aucilla River, Florida contains many types of aquatic plants, including most discussed here.  Cypress was the most common item in their diet, but the beasts ate nympoides, nymphaea, and this one–burreed.  Burreed is an important plant in the second stage of forest succession that occurs when islands develop within the swamp.

The five stages of forest succession in the Okefenokee Swamp

1.  Sphagnum moss floats to the surface of open water and soil begins to accumulate on it forming an island.  Beakrush takes root.

2. Burreed, panic grass, and redroot are the second stage of plants to colonize the island.

3. Sedges take over.

4. Bushes and saplings colonize the island.

5. Trees such as cypress, tupelo, water oak, and pond pine form the final components of island forest succession in the Okefenokee Swamp.

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2 Responses to “The Geological and Ecological History of the Okefenokee Swamp (part three)”

  1. Beth Walters Says:

    Could you give me a citation on the presence of Spanish Moss 7,000 BP? It would help with some bioarchaeology research I am doing. Thanks!

  2. markgelbart Says:

    I don’t know, if scientists have ever excavated Spanish Moss from 7,000 years ago. Scientists excavating the Okefenokee Swamp found Sphagnum Moss which is not a relative of Spanish Moss.

    The source for my 3 part series on the Okefenokee is:

    Rich, Frederick; and Gale Bishop
    Geology and Natural History of the Okefenokee Swamp and Trail Ridge, southeastern Georgia and north Florida
    Georgia Geological Society Field Guides

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