from the woods near Natchez, Mississippi, USA
November 30, 2003
MIST TORNADOES & FROST SPARKLES
Last Sunday around noon my thermometer read 80° (27°C), then that night a strong front moved through leaving an inch of rain (2.5cm), and by Tuesday morning we had our first freeze of the season, at 25° (-4°C). In Mississippi I have never seen such a heavy frost, making the neighbor's pastures at dawn silvery white with Black-Angus silhouettes. In the Loblolly Field, hoary-headed goldenrods rose hunchbacked from an infinity of arching, crystal-margined leafblades of Little Bluestem. The Loblollies themselves were almost black in contrast, and their green-needled outer branches were frosted as prettily as any plastic Wal-Mart Christmas trim.
When the sun's first rays flooded in from the east, I stood next to the pond facing the sun, glad to feel warmth on my legs and face. No ice had formed on the pond, but mist rose from the dark water in dense billows. The pond lay between the sun and me so the backlighted mists glowed with uncanny energy.
An erratic breeze caused the mists to curl and scoot across the pond's surface with a swift nervousness almost out of place on such a placid morning. Sometimes the mists would build into nebulous statues and igloos, then suddenly they'd all be swept away, and the mist-theater would reformulate.
Black Willows with yellow, frost-laced leaves stood along the pond's banks. When a breeze stirred, a few leaves would fall -- yellow flutterings onto black water -- and powdery frost crystals would spray through the sunlight sparkling white, red, green and blue.
Most amazingly, every few minutes the mist-causing tension between warm pond water and freezing air would cause the mists to spontaneously curl into fast- moving, arm-thick, yard high, silently spinning mist- tornadoes. At one time five mist tornadoes spun across the black water. Simultaneously a certain breeze spread a spray of backlighted yellow willow leaves and glistening frost crystals across the five-tornado scene.
These phenomena coexisted for only three or four seconds. Then the tornadoes vanished, the yellow leaves and frost sparklings were extinguished in black water, and all mists cleared from the pond's surface.
Then long I stood, unwilling to break with the charmed moment. But the new mists that formed atop the pond were of a common type. Now when willow leaves fell, no frost crystals accompanied them.
I think that only once in a lifetime can such a conjunction of magical events occur, and I was honored to have been a witness.
On no single day in the year does nature change more profoundly than on the day of the first heavy frost. What a sight my gardens were Tuesday morning as the frost melted.
The Elephant Ears and cannas, which for so long have pleased with their robustly broad, glossy-green leaves, now lay crumpled in pitiful, darkened heaps. Basil leaves dangled limp, dark and greasy looking. The tomato vines were blackened, the cucumber vines looked as if they had been scorched, and the okra leaves were warped and twisted.
Some plants survived without visible damage. The horseradish, radishes, turnips, turnip greens, mustard greens, cabbage, broccoli and kohlrabi all looked good, as did the garlic and green onions.
Having gardened for many years, I had known which plants would die and which would live. Still, I was again impressed by how well the green onions survived. At dawn I had pulled a big one to snip into my cornbread batter. The onion's hollow, cylindrical blades had been so packed with white ice crystals that the blades were stiff. Yet, once the onions remaining in the garden had warmed, their blades returned to being as green, pliable and healthy as ever.
Back in the 70s when I studied plant physiology, freeze damage to plants was regarded mainly as a consequence of sharp ice crystals lacerating sensitive cell membranes, and expanding crystals bursting fragile xylem and phloem tubes. Since then, ideas on freeze damage have shifted in new directions.
In a 2001 paper called "Plant Freezing and Damage," in the eminent technical journal ANNALS OF BOTANY, I read that "The single most important cause of freezing- damage is when ... dehydration exceeds what cells can tolerate." In other words, instead of physical damage done by ice crystals, now it is known that freezing mainly affects plants by depriving their tissue of water.
The paper also focuses on the fact that for an ice crystal to begin growing it must first have an appropriate very tiny item to serve as a nucleus, something called a nucleator. It's now known that often certain bacteria produce a protein that can serve as a nucleator.
If your computer can handle PDF files and you yourself aren't daunted by fairly technical papers, you might want to download the "Plant Freezing and Damage" paper at http://aob.oupjournals.org/cgi/reprint/87/4/417.pdf
DIGGING DUCK POTATOES
The other day neighbor Karen Wise dropped by and we went digging Duck Potatoes. "Duck Potatoes" is just one of many names applied to the plant, one I've never heard regular people use, but I like it better than the usual book name, Broadleaf Arrowhead, SAGITTARIA LATIFOLIA. You can see what the plant looks like at www.pwrc.usgs.gov/history/herbarium/sagittaria_latifolia.htm
Duck Potato is an aquatic plant about knee high, often growing in the bottom of drainage ditches and at the edge of ponds and lakes. Some grow in the ephemeral little sandy-bottom stream passing by the barn, and this is where we dug them. The species is found throughout most of North America.
The mature Duck Potato plant sends out underground runners at the end of which, maybe 15 inches (40 cm) from the plant's base, you find either a new plant sprouting, or a "duck potato." This tuber is white, somewhat egg-shaped, and about the size of a golf ball. Its flesh is harder than a regular potato's, but still it is succulent enough that if you have solid teeth you can bite into it. Its raw taste is bitter to a human but if it's boiled for about 30 minutes or roasted in campfire embers, its taste becomes similar to that of a white potato.
You can imagine that American Indians and early settlers ate duck potatoes with relish. Lewis and Clark developed a high regard for it. From what I can determine, ducks don't really eat a lot of this particular species because the tubers form too deep in the mud. It's a different matter with muskrats, however. In fact, I've read that the Indians often got most of their tubers from stores already assembled by muskrats.
Though the water was cold, Karen and I had fun digging our tubers. I think our hunter-gatherer instincts were aroused. With our fingers poked into the mud following underground runners, anticipation would build as we'd approach where we thought the tubers would be. Then when we found a large, well-formed one, it was a real treat. Seeing our collection of wholesome, nutritious tubers after a period of hard work was enormously gratifying.
We didn't eat our tubers, however. The next day I planted them all along our pond's banks in the hope that next year there'll be a nice population of them. Then maybe within a few years they'll be thick enough for us to dig tubers and eat them without feeling bad about depleting the population of this very pretty, important species.
On Tuesday morning, Mississippi's Public Radio system presented a special segment on Cogon Grass, IMPERATA CYLINDRICA. This is an introduced Asian weed that seems to be even more aggressive and ecologically threatening than Crabgrass and Kudzu, and it is spreading rapidly in Mississippi. The radio program asserted that Cogon Grass is considered the seventh- most serious invasive plant, or weed, on a worldwide basis.
Though I have not seen Cogon Grass here, the program specifically said that in Mississippi it has spread "as far west as Natchez." Already the plant is found in over half of Mississippi's Counties, basically those constituting the state's southern half, and it is spreading northward fast. It has been reported surviving as far north as Virginia, West Virginia and Maryland. We all would do well to know what this species looks like, and to destroy it when we find it.
The US National Park Service provides a Web page discussing the species and providing several photos to help in identification at www.nps.gov/plants/alien/fact/imcy1.htm
LAND PLANARIANS AFTER A BIG RAIN
In the Newsletter of December 16, 2001 I wrote that I'd found a land planarian, BIPALIUM KEWENSE, at Laurel Hill Plantation. Since Bipalium kewense is a native of Southeast Asia that has been introduced into the US by way of the soil of imported potted plants, I figured that my discovery was a very local find. I couldn't find any reports of it having been found in the wild in Mississippi.
Wednesday night we had another big rain, once again more than filling my three-inch-high tin cup. On Thanksgiving morning the ground was saturated, and that may be the reason I found three dark-brown Bipalium kewenses about five feet up the barn's exterior cinderblock walls. They were all curled up into knotty, mucous-covered masses. If they had been stretched out, they would have extended six inches or so (15 cm). Clearly, this species is more common in our region than I had thought.
Land planarians are amazing creatures. They are members of the Flatworm Phylum, the best-known members of which are the tapeworms of intestinal parasite fame. They can reproduce sexually and lay eggs in cocoons, but the most frequent manner of reproduction is by "fragmentation." At a certain time, at a point about 0.4 inch (1 cm) from the worm's rear end, the worm's sides pinch in, and continue pinching in until the rear end simply breaks off. The rear end then goes one way and the main worm body goes another. Within seven to 10 days a head begins forming on the pinched- off end. One or two such fragments are released each month.
If you've taken a biology class, you may have conducted experiments on a planarian's nervous system. If you cut a planarian's head down the middle, lengthwise, a two-headed planarian my result. Sometimes if you just cut the head off a worm, a being will result consisting of nothing but two heads pointing in opposite directions, joined neck-to-neck.
Bipalium kewense eats earthworms, slugs, insect larvae and other planarians. I'm not sure how much of a threat this introduced species is to our native earthworm populations, but I doubt that they do themn much good.
You can see this species and read all about it at http://creatures.ifas.ufl.edu/misc/land_planarians.htm
EASTERN OLD GROWTH FORESTS
A while back I corresponded with Mary Byrd Davis, editor of "Eastern Old-Growth Forests: Prospects for Rediscovery and Recovery" (Island Press, 1996), about the status of old-growth forests on the loess-capped bluffs along the Mississippi River's eastern shore. Her book's goal is to "describe all old-growth sites in the East (over 40 acres in size) that are known to researchers." This week she writes me that she's updated her book, which can be reviewed and ordered at www.old-growth.org/book.html
"The Eastern Old Growth Clearinghouse" homepage is at www.old-growth.org/intro.html
THE CHIGGER/ REDBUG QUESTION
Last week I asked readers to help me figure out where people call chiggers chiggers, and where they call them redbugs.
We have seen that in Kentucky and Tennessee they are chiggers, but in Alabama they are redbugs. Leona in southeastern Missouri calls them chiggers, and adds that "In Michigan we called em chiggers too, though my dad sometimes called them jiggers. Dad may have been talking 'scottish'...his father was a first generation over scot, and Dad's brother called bombs booms and Dad called tassels tawsels..."
Cindy in Michigan of course calls them chiggers but, interestingly, says that her grandparents from Arkansas and Oklahoma did, too. Right across the Mississippi River from southeastern Arkansas lies the Mississippi Delta. Jerry who grew up there says that he learned to call them redbugs. Does the Mississippi River in that area form the chigger/redbug boundary?
Barbara in central Alabama confirms that they're redbugs there, and reminds us that "We all know that our beautiful Spanish moss hanging from the trees is infested with REDBUGS! Kids always want to play with it but adults are always yelling 'Don't play with it, it's full of redbugs!'"
By now we can guess that Sue Nell in Louisiana would call them redbugs, and that's the case.
Hillary who grew up in Natchez calls them redbugs and informs us that "Red bugs don't bite .. they secrete a proteolytic enzyme into a skin pore and digest the epithelium."
The most intriguing response came from Karen in Kingston, near Natchez. Her impression is that "upper class folks" say redbugs, but the rest of us say chiggers."
FROST AND GREEN TOMATOES
On Monday, knowing that the freeze that night would kill the tomato vines, I went around collecting green tomatoes, to store until they ripened. It seemed easiest to pull up each plant by the roots, then hold the vine before me as I plucked the tomatoes, so this I did. However, it felt funny.
I felt queasy because all summer I'd babied those vines, and the vines had been good to me. I'd eaten from them, watched Green Anoles and Fence Lizards stalk quarry among them, I'd savored the architecture of their blossom anatomy and watched individual flowers gradually develop into perfect fruits. Yet now I broke roots and stems, plundered half-grown fruits, and tossed the mangled plants onto the ground to be forgotten.
The uneasy feeling haunted me all day, and I wondered why. Something here touched a deep chord within me. Something toyed with my subconscious.
After a couple of days I understood. The act of uprooting treasured tomato vines before the first big frost was nothing less than a metaphor for how I have conducted my own life at many critical junctures. Again and again in this life I have come to understand something that had been hidden to me before, and then I have quickly and irretrievably uprooted treasured, even sacred and certainly society-encouraged notions and beliefs, I have abandoned comfortable and safe routines, and at those times I have left much in my wake to molder as it would.
When I had those pitiful tomato vines in my hands, prematurely ripping off their long-nurtured fruits, it was exactly like the day in the mid 60s when I became a vegetarian, like the day in the mid 70s when I stopped being a botanist at the Missouri Botanical Garden, never again to lead a standard life. It was like so many times I have behaved absolutely rationally, and perfectly within the letter of the unspoken contract between the world and myself, and accomplished a change that all too often was accompanied by pain on many levels.
These words you are reading right now, and my being where I am and what I am, are part of the most recently planted, modest little tomato plant just poking from the soil, the latest seedling of many that have vined and fruited, and been pulled up before it faded naturally. We'll just see what happens to this one as my own Big Frost draws nearer and nearer.