Some plants are found in many places – tuliptrees (Liriodendron), sweetgum
trees (Liquidambar ), red maples (Acer rubrum), Canadian goldenrod (Solidago canadensis) and others are everywhere around me. But
some plants are only found in special places. Places that have just the right
environment, the right minerals, soil levels, moisture levels and other special
characteristics. I visited just such a place last week – a place known as an
“outcrop”.
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| Diamorpha in Dicranum moss |
After I visited that area, I happened to pick up my 2012
issue of
Tipularia, The Journal of
the
Georgia Botanical Society. The first story in the issue is “Piedmont
Outcrops, Overgrown and Under Fire.” The author explained that “granite
outcrops of the southeastern United States are a treasure-trove of rare plant
species.” The first picture in the article showed two of the plants I had just
seen:
Diamorpha smallii and
Tradescantia hirsuticaulis. It was
interesting to read about the very difficult conditions that these outcrops
create for their resident plants. High temperatures and thin soils require
specially adapted plants. Some plants grow when moisture is plentiful and then
die out during the hot months, leaving seeds for the cycle to start again
later.
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| Outcrop fringed by grasses and trees |
When I first entered the area, it was like entering a meadow
in the middle of a forest – a big clearing with some dried grasses on the
edges. As my eyes adjusted to this unusual sight, I realized it was a huge area
of rock, covered in some areas with moss and low growing plants and exposed in
others as bare rock. I could quickly see from the color variation that even the
moss population was diverse: I recognized the lush bright green of
Dicranum scoparium and the dark, grey areas of
Grimmia laevigata. Mixed in were some pale green lichens and at
least 3 other species of moss. These plants, which benefited from small
collections of soil on the rock themselves, now provide areas for seeds to
gather and sprout.
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| Diamorpha smallii in Grimmia laevigata |
Throughout the area was the small annual sedum known casually
as “diamorpha” (
Diamorpha smallii) or
Small’s stonecrop. Only the leaves were present now; it will bloom later in the
spring with small, starry white flowers reminiscent of other native sedums.
Even without blooming, the succulent red leaves offer stunning color and beauty
on the bare rocks and mixed into the moss. In areas of deeper soil, more
perennial plants like the hairy spiderwort (
Tradescantia hirsuticaulis) and grasses were found. Even a few
trees had managed to survive over time (including some stunted invasive privet
and Japanese honeysuckle).
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| Small vernal pool surrounded by mosses and Diamorpha |
In one area was a small pool. Floating in the pool was more
Diamorpha. Dried tuffs of moss
surrounded it, no doubt waiting to be reinvigorated with the next spring rain.
The whole effect was quite beautiful, as if we had stumbled upon a fairy world.
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| Diamorpha floating in pool, tethered by a long stem |
Georgia is a unique place for granite outcrops. According to
the article in
Tipularia, “Approximately 87% of all granite outcrop habitat area occurs in
Georgia and the majority of outcrops exist within sixty miles of Atlanta.
If you are interested in exploring an outcrop
in Georgia, here are some suggestions:
In the month of March, several areas are sponsoring an event known as
Monadnock Madness to help people learn more about these special places. The event is described on their website: “In March (2013), you can experience
these unique places first-hand through guided hikes and free tours at Arabia,
Panola, and Stone Mountains. If you can conquer all three peaks during the
month you’ll earn a special souvenir that you can wear as a badge of
honor.”
Check it out at the hotlink above and take this opportunity to discover some of Georgia's unique natural environments.
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