Today’s report
was written by Dale Hoyt. The photos that appear in this blog are taken by Don
Hunter; you can see all the photos Don took of today’s
Ramble here.
Sixteen ramblers met at the Arbor at 8:00AM on a
beautiful, cool morning just right for a ramble.
Today’s
reading: Dale read an excerpt from Joseph Wood Krutch’s essay, Man’s Ancient, Powerful Link to Nature:
On
some summer vacation or some country weekend we realize that what we are
experiencing is more than merely a relief from the pressures of city life; that
we have not merely escaped from something but also into something; that we have
joined the greatest of all communities, which is not that of men alone but of
everything that shares with us the great adventure of being alive.
Announcements:
1. Next week’s ramble will be the last of the
year to start at 8:00AM. Beginning in September all our rambles will start
at 8:30AM.
2. Sandy Creek Nature Center will resume their monthly
guided trail walks in September.
The walks begin at 9:00AM on the first Wednesday of the month; meet at the
Visitor Center. The first walk will be on September 2 and will be led by Sandy
Creek’s expert naturalist Carmen Champaign.
3. The University is celebrating the 250th
anniversary of John and William Bartram’s Natural History Expedition in
Colonial Georgia. Over the next month and a half there will be a variety of
presentations about the Bartrams. Visit this website for
more information about the planned events.
At the Arbor:
Before starting the ramble we discussed last week’s discovery of a dead Green
Ash tree on the Orange trail. We were fearful that the tree had been killed by
the Emerald Ash Borer (EAB), an insect that is decimating ash trees in the
North and rapidly spreading across the country. Last Monday several experts
examined the tree and found no evidence of the EAB. The tree was killed by an
infestation of bark beetles. We can breathe a sigh of relief, for a while
anyway. The EAB is already in Georgia (since 2013) and it is only a matter of
time before it arrives in Clarke Co. Visit this
website for up-to-date information about the EAB in Georgia.
Eleanor brought an interesting find from her house –
a small scorpion. We only have a single scorpion species in this part of the
state: Vaejovis carolinianus AKA Southern Unstriped Scorpion, a terribly
awkward name. This species is small and uniformly dark in color. It is typically
found outdoors, under bark or rocks, and only occasionally found in houses. Over
the last thirty years we can only remember finding one in our house. These scorpions
have a painful sting, like a wasp, but the discomfort lasts less than an hour. The
main problem from a sting arises if you are hypersensitive to the venom. In
that case medical attention is needed.
Today’s route:
From the arbor we strolled down the cement walkway through the Shade garden to
the Dunson Native Flora garden. There we wandered the paths and at the bottom
of the Dunson garden we exited and walked up the road to the White trail.
Turning left on the White trail we proceeded to the power line right of way and
walked a short distance uphill before turning around and returning to the
arbor.
Shade Garden:
One of our new ramblers, Marianne, recently moved here from the Northeast and
wanted to know how to identify Ash trees, so we stopped in the shade garden to
point out a small White Ash. The two commonest Ash species found in Georgia are
the Green Ash and White Ash; Green being the most common in this area. (White
Ash is more abundant in the mountains.) Both Ashes have compound, opposite leaves; those of Green Ash
usually have 5 leaflets while White Ash typically has 7 leaflets. The bark
ridges of Ash form skinny diamond shaped patterns on the trunk, but this
characteristic is also found on some of the local hickory species. (But the
hickories have alternate, compound
leaves.) In fact, we found a tree near the labeled White Ash that had that
typical diamond-mesh bark and compound leaves. But there was some disagreement
about whether it was an ash or a hickory. Some of us saw clearly opposite
leaves, but others pointed out that the leaflets looked more like those of a
hickory. We left with no clear decision.
Dunson garden:
Our focus today was on ferns, but we didn’t neglect other things we saw. I’m
going to organize this section around these topics: ferns, other plants and
caterpillars.
Ferns: I
prepared a Fern minibook to help identify seven ferns commonly seen on the
Orange and other trails as well as the Dunson garden. Click here
to get the booklet; you can download and print it from Microsoft Word.
A good
book to help you identify ferns is: Field
Guide to the Ferns and Other Pteridophytes of Georgia by
·
Small
brown patches often found on the underside of a frond. Each sorus is a group of
much smaller structures, called sporangia
(sing., sporangium).
·
Sporangium
(pl., sporangia): Each sporangium
produces numerous microscopic spores.
·
Sporophyte:
A plant that produces spores.
·
Spore:
A type of reproductive cell produced by a sporophyte. Spores in ferns are
produced by a special kind of cell division called meiosis.
·
Meiosis:
A kind of cell division that produces spores in ferns or gametes (sex cells,
eggs or sperm) in animals. Fern spores and animal gametes carry only one set of
chromosomes The cells that produce the fern spores or animal gametes have two
sets of chromosomes.
Mitosis:
A kind of cell division that produces daughter cells that have all the chromosome
sets of their parent cell.
·
Ferns we saw:
Sensitive fern, Royal fern, Christmas fern, Ebony spleenwort, Southern
maidenhair fern, Northern maidenhair fern, Broad beech fern, New York fern,
Cinnamon fern and Marginal wood fern.
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| Southern Maidenhair fern |
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| Northern maidenhair fern |
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| Royal fern |
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| Ebony spleenwort |
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| Marginal wood fern |
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| New York fern |
The distribution of sori on the frond is an aid to
identifying ferns. Each kind of fern usually has a characteristic location and
pattern where the sori are found. Some examples:
Christmas fern: The sori are found on the underside
of the pinnae toward the end of the frond. Not every frond develops sori, but,
in those that do, the pinnae that bear the sori are distinctly smaller than the
sterile pinnae.
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| Christmas fern; fertile pinnae at end of frond |
Sensitive fern: The sori develop on a fertile frond
that is separate and completely different looking than the sterile frond.
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||
| Sensitive fern fertile frond (center) surrounded by sterile fronds |
Marginal wood fern: The sori develop next to the
edges (the margin) of the pinnae.
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| Marginal wood fern Sori located near edge of pinnae |
Fern
reproduction: Ferns can reproduce vegetatively, by sprouting new fronds or sending
out rhizomes that produce more fronds some distance from the parent plant. In
these cases all the fronds are genetically identical clones. Ferns can also reproduce
sexually by producing spores.
Spores vs.
seeds: There is a tendency to think of spores as seeds since both are
important in propagation of their parent plants. But spores are very different
from seeds.
Firstly, fern spores are usually single cells and
have little or no nutritive material to support their growth. When a spore
germinates it is on its own; it must be able to make enough food via
photosynthesis to support its future growth.
In contrast, a seed contains a multicellular
embryonic plant plus a supply of food to support the developing embryo. When you
eat cereal grain products you are actually consuming the seed’s nutrient store,
mostly starches and oils, intended for the embryonic plant. In fact, during food
processing, the embryo is discarded to make wheat flour, white rice and grits, so,
unless you eat whole grain wheat or brown rice, you’re missing out on the
nutrients found only in the embryonic plant.
Another difference is the type of plant that is
produced by a fern spore and a seed. When the fern spore germinates and grows
it does not develop into a sporophyte. It becomes a small, green plant about
the size of your little fingernail. This plant is known as a gametophyte
because it will produce egg and/or sperm cells. (The general term for sex
cells, egg or sperm, is gamete, hence, this plant is a gametophyte – a gamete
producing plant.) Once the sperm cell finds an egg cell and fertilizes it the
resulting zygote now has two sets of chromosomes. The embryo develops, through
the cell divisions of the zygote, into a sporophyte. The developing sporophyte
is initially dependent on the gametophyte for its nutritional support.
What kind of plant is produced by a seed? It has two
full sets of chromosomes in each cell so it must be a sporophyte. So what are
the spores that are produced by a seed plant sporophyte? They are familiar to
you as the pollen and the ovules. Because they are different in size botanists
call them microspores and megaspores, respectively.
Other plants:
Only a few flowers were blooming today and they were looking a little ragged
after being beaten by the heavy rains of the last several days. The Catch fly
we saw last week was still in flower, as were the skullcaps and the elephant’s
foot. We also found the bright red berries of Jack-in-the-pulpit.
Critters:
We found three caterpillars and one spider today. Of the caterpillars the most
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| Spun glass slug moth caterpillar |
bizarre was a Spun glass slug caterpillar. This caterpillar is a member of the
moth family Limacodidae, the Slug moths. They are named for the way in which
their caterpillars move. Most caterpillars have fleshy legs on their abdomen
that they use for creeping across leaves and twigs. The slug moths have instead
a sucker on the belly and they use it to glide along, something like a slug,
hence, the common name. Many caterpillars in this family have stinging hairs on
the body. If you contact them with your skin you will feel a burning sensation
similar to that produced by stinging nettles. The spun glass slug that
Catherine found is young; as it grows the fine, glass-like projections will increase
in number and grow longer.
The spider, a triangulate orb weaver was spotted by
Don and is small this early in the
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| Triangulate orbweaver |
season. (They were even smaller in the
spring.) Most of our orb weaving spiders are annual species – they only live
one year. Typically the female lays eggs in the fall and then dies. The eggs
overwinter and hatch in the spring. The early part of the year the baby spiders
are so small that they are seldom seen, but as they feed they grow larger and
finally become noticeable when they reach a size that can produce a web we run
into when we walk the trails..
White trail:
After leaving the Dunson garden we walked up the road to the White trail and
checked on the American beech tree we have been watching all summer. The
beechnuts are turning a darker shade of brown and Don sampled one, reporting
that it was pretty astringent, but not as bad as an unripe persimmon.
The trail passes by what used to be the flower garden
and we still find some of those plants
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| Lycoris sp. flower |
hanging on. Today we found a number of
Lycoris still bearing rain-beaten flowers. These plants have many different
names: Surprise lily, Hurricane lilly, Rain lilly. About this time of year they
send up a flowering stalk with no leaves. The sudden appearance of the blooming
stalk led to the “Surprise” name. The Hurricane and Rain common names
probably refer to the time of year and weather conditions that seem to prevail
when the flowers pop out of the ground.
The Hophornbeam further along the trail has a huge
number of papery fruits, each with a small seed at the base. We’ve also been
watching the progress of this tree and the seeds are ripe and ready to drop off
the tree.
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| Ripe fruits of Hophornbeam |
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| Each papery fruit holds a single seed |
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| Purpletop/Greasy grass |
Powerline:
The power line continues to put on a display of flowers and grasses. The most
prominent flowers today were
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| Beaked panic grass |
the Mountain mints and Late flowering
thoroughwort. The Purpletop (or Greasy grass) was especially noticeable and
there was an abundance of what I initially thought was a sedge. (My moment of
embarrassment!) I twiddled the stems and felt edges. Following the old
mnemonic, “Sedges have edges,” I jumped to the wrong conclusion. The
stems were not triangular. Emily snapped a photo with her cell phone and sent
it to Linda Chafin who identified it as Beaked panic grass. It is spectacularly
abundant this year! Other flowers that we noticed amidst all the grass were
Field thistle and a few Carolina desert chicory.
Then it was time to return and the usual crew
gathered at Donderos’ for snacks and beverages.
Dale Hoyt
SUMMARY OF OBSERVED SPECIES:
|
Lady Fern |
Athyrium filix-femina |
|
White ash |
Fraxinus americana |
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Christmas fern |
Polystichum acrostichoides |
|
Sensitive fern |
Onoclea sensibilis |
|
Northern red oak |
Quercus rubra |
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Black snake root |
Sanicula sp. |
|
Royal fern |
Osmunda regalis |
|
Ebony spleenwort |
Asplenium platyneuron |
|
Triangulate orb weaver |
Verrucosa arenata |
|
Thick leaf/ovate leaf catchfly |
Silene ovata |
|
Northern horse balm |
Collinsonia canadensis |
|
Southern maiden hair fern |
Adiantum capillus-veneris |
|
Asiatic day flower |
Commelina communis |
|
Hairy skullcap |
Scutellaria elliptica |
|
Elephants foot |
Elephantopus tomentosa |
|
“Pancake” mushroom |
Not identified |
|
Northern maidenhair fern |
Adiantum pedatum |
|
Broad beech fern |
Phegopteris hexagonoptera |
|
Cinnamon fern (?) |
Osmundastrum cinnamomeum |
|
New York fern |
Thelypteris noveboracensis |
|
Slug moth capterpillar |
Family Limacodidae |
|
Marginal wood fern |
Dryopteris marginalis |
|
Jack in the pulpit (berries) |
Arisaema triphyllum |
|
Banded tussock moth caterpillar |
Halysidota tessellaris |
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American beech tree |
Fagus grandifolia |
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Surprise lily |
Lycoris sp. |
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Hophornbeam |
Ostraya virginiana |
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Marasmius mushroom |
Marasmiellus sp. |
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Late flowering thoroughwort |
Eupatorium serotinum |
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Purpletop/Greasy grass |
Tridens flavus |
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Beaked panic grass |
Panicum anceps |
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Mountain mint |
Pycnanthemum incanum |
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Field thistle |
Cirsium discolor |
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Carolina desert chicory |
Pyrrhopappus carolinianus |
|
Butterfly pea |
Clitoria ternatea |
|
Garden snail (tentative) |
Cornu aspersum |
|
Orange striped oakworm |