Friday, June 12, 2009

The Amazing Spiderwort



It has been great fun to get more acquainted with wildflowers this year. I only regret that I’ve waited so long to give them the attention they deserve. The past couple of weeks had been a fairly slow time for finding new flowers. As the trees leafed out and the forest canopy closed, the early spring flowers deep in the woods have faded.

Now, it’s time to look elsewhere. This week, a flower hunter could do worse than to look alongside the Blue Ridge Parkway from Balsam Gap to Waterrock Knob. Rhododendrons and flame azaleas are hard to miss, even if you’re zipping past at 45 MPH. But anyone who gets out and takes the time to look will find lots and lots of smaller flowers blooming. I’m still culling from a couple of hundred photos I took there this week.

The spiderwort, one of the few flowers I could have identified before this year, is blooming in abundance. I enjoy taking macro shots, and even though a photographer might pass up the spiderwort for more charismatic flowers, it is a splendid subject if you stop and take a closer look. Generally speaking, bright sun is not the ideal condition for taking wildflower pictures. I’ve found, though, that with flowers that lend themselves to close-ups, the bright sun helps in achieving clear, sharp results. Predictably, this is less true for white flowers. For some reasons I don’t quite understand, yellow flowers are even more difficult to photograph well in bright light, at least in my experience. That’s not a problem with the blues and purples of the spiderworts.

I had known that the spiderwort was of particular interest to botanists although I had forgotten why. They have several notable characteristics:

-The plants are easily hybridized.

-Their cell structure makes it relatively easy to observe the flow of cytoplasmic fluid through the plant.

-Due to its large chromosomes, spiderwort is the plant of choice for viewing (under a microscope) cell division in the stamen hairs.

-Old petals don’t fall from the flower, as with most plants, but seem to melt due to certain enzymes.




One of the most curious traits of the spiderwort is its response to ionizing radiation, such as gamma rays. Upon exposure, the stamen hairs which are normally blue will turn purple or pink. So the plant is studied as a natural barometer of air pollution and radiation. Less than two weeks after contamination from low “safe” doses of radiation or hazardous chemicals the stamen hairs will start to mutate and change color. Since the spiderwort can absorb toxins and store them internally, it gives a more useful measure of the cumulative effect of contamination over time, compared to other means of measuring external and temporary levels of toxins.

Reportedly, the Cherokees used the spiderwort for food and medicine. The young leaves were eaten as salad greens. The plant was mashed into a paste and rubbed onto insect bites to relieve itching and pain. The roots were used in a poultice to treat cancer. A tea made from the plant was used as a laxative and for stomachaches.






If I have identified it correctly, the spiderwort I found in such abundance along the Parkway this week was the Mountain Spiderwort, Tradescantia subaspera var. montana. Fortunately, thanks to some prior study of the wildflower guide I had known to be alert for another member of the spiderwort family. Otherwise, I might have ignored the Commelina communis as more of the same. As with the Mountain Spiderwort, this plant has three petals, but it would be easy to assume that it is missing one. While two of the petals are blue (and bluer than the Mountain Spiderworts that I’ve seen) the third petal is smaller, white, and easily overlooked. Some people call this plant Mouse Flower since the two blue petals do resemble a pair of mouse ears. But it is better known as the Common Dayflower, which refers to the blooms lasting only one day before melting away.

Spiderwort

I always see my father's eyes as blue
When spiderwort comes up in spring. I saw
It first when no one in Nebraska knew
What name it had in Gray's old botany.

None but my father. He would leave his team,
Take down the book he'd sold the seed-corn for,
Scan page, and say: "That's spiderwort." In fall,
"Oh, no, not weeds. That's blazing star." I'm glad

Except for what my mother must endure,
He left us hungry, chased some wan, wild goose;
But told me names of shepherd's purse in spring
And tumble-weed and golden-rod in fall.

- Margaret E. Haughawout (1929)

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