Today’s Ramble was led by Linda Chafin.
Here’s
the link to Don’s Facebook album for today’s Ramble. (All the
photos in this post are compliments of Don.)
Today’s post was written by Linda Chafin & Dale Hoyt.
Today’s Focus:
26 Ramblers met today.
Announcements:
Congaree National Park field trip: A small group of Ramblers
decided to visit Congaree National Park, outside of Columbia, SC, Nov. 9 – 11,
2018, stimulated
by a recent article in the New York Times. If any other Ramblers are interested in joining us you can find more details on our Announcements page.
Nature Rambler book club: Linda and Dale have been talking about a
book club that would focus on “nature” books, broadly defined. Before we get
started we need to find a free place to meet once a month. If you know of such
a venue please email suggestions with the Subject line “NR book club,” to Dale.
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| Catalpa “worm” (really a caterpillar) |
Show & Tell: Gary
brought in a “catalpa worm” aka “catawba
worm” which is actually a caterpillar
of a Hawk Moth (also known as Sphinx Moths). The adult moth lays its eggs on
Catalpa Tree leaves and the caterpillars emerge 5-7 days later. They are
capable of completely defoliating a tree several times during a summer, but the
trees recover. Catalpa worms, known as “catfish candy,” are popular for fishing
and can be frozen and thawed for fishing later in the year.
Today’s reading:
Linda read this poem by David Wagoner:
Lost
Stand still. The trees ahead and bushes beside
you
Are not lost. Wherever you are is called Here,
And you must treat it as a powerful stranger,
Must ask permission to know it and be known.
The forest breathes. Listen. It answers,
I have made this place around you.
If you leave it, you may come back again, saying
Here.
No two trees are the same to Raven.
No two branches are the same to Wren.
If what a tree or a bush does is lost on you,
You are surely lost. Stand still. The forest
knows
Where you are. You must let it find you.
Today’s route:
We left the Visitor Center, via the back
door, and headed across the Herb and Physic Garden to the head of the Purple
Trail by the sod-roofed garden shack. We
took the Purple Trail all the way to the river and turned left on to the Orange
Trail, which we took down the river and around the beaver pond. At this point we returned the way we came
back to the Cafe Botanica in the Visitor Center.
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| Jimson Weed flower |
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| Jimson Weed fruit |
Jimson Weed is
planted in the Herb and Physic Garden because it was used by Native Americans to treat asthma. It has also been
used as a hallucinogen but this is very risky–the difference between a toxic
dose and a psychoactive dose is very small. The sweet-smelling flowers open at
night, are pollinated by sphinx moths, and produce oval, spiny capsules. The
common name is based on Jamestown, Virginia, where British soldiers “ate
plentifully” of the plant and spent 11 days in a state of delirium, folly, and
“innocence and good nature.” (From Wikipedia — Robert Beverley, Jr., The
History and Present State of Virginia, Book II: Of the Natural Product and
Conveniences in Its Unimprov’d State, Before the English Went Thither, 1705)
This link
will give you access to an interesting paper that connects Datura with the
discovery of three human disease syndromes.
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| Female Tiger Swallowtail Note the blue frosting on the black margin of the hind wing. |
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| Male Tiger Swallowtail Note the absence of blue frosing on the black margin of the hind wing. |
Dale captured a male Tiger Swallowtail and showed us how
to tell male from female. This butterfly has a solid black band on the
hindwing, indicating it is a male. A female would have a black band sporting
dense blue scales on the upperside of the hindwing. Female Tiger Swallowtails
have two color forms: one is black and yellow like the male and the other is all
black. Both of the female color variants
have the blue pattern on the upper hindwing margin.
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| Northern Red Oak still standing; how long will this one last? |
Staff at the Garden have noticed that a lot of large oaks
have fallen during the last 10 years, and most of them are Northern Red Oaks.
We saw several today that had been blown over along the trail. The speculation
is that they were weakened during the severe drought of 2010-2012 and
subsequent shorter droughts and are more vulnerable to wind-throw now. Research
conducted at the Warnell School of Forestry at UGA showed that Northern Red Oak
seedlings have a loss of growth, fecundity, and biomass when subjected to
drought. Northern Red Oaks are very near their southern limit along the
Atlantic Seaboard in Athens; their range ends around Macon. Given that drought
and storm intensity are expected to increase over the next 30 years, it seems
likely that we are witnessing the beginning of the end of Northern Red Oaks
here in the Piedmont–large trees are dying and seedlings will have a hard time
establishing. The species will persist in the north Georgia mountains and
further north, but the loss of a species on the periphery of its range means a
loss of genetic diversity.
References:
Cavender-Bares,
J., M. Potts, E. Zacharias, and F.A. Bazzaz. 2000. Consequences of CO2
and light interactions for leaf phenology, growth, and senescence in Quercus rubra. Global Change Biology
6(8): 877–887.
Bauweraerts,
I., M. Ameye, T.M. Wertin, M.A. McGuire, R.O. Teskey, K. Steppe. 2014.
Acclimation effects of heat waves and elevated CO2 on gas exchange
and chlorophyll fluorescence of northern red oak (Quercus rubra L.) seedlings. Plant Ecology 215(7): 733-746.
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| Chanterelle mushroom |
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| False Turkey Tail |
Today was a good day for spotting fungi: Chanterelles and
other mushrooms on the soil, and False Turkey Tails on downed trees were
abundant. Of course, what we see above ground is only a tiny fraction of the
fungal body; the mushroom is the part that produces spores. The bulk of a
fungus is underground–long white strands called hyphae collected together into
a vast, much branched colony called a mycelium. Research over the last few
decades has shown how important fungal colonies are to the health of the
forest. By breaking down dead plant matter, they make nutrients available in
the soil. By connecting trees to some non-photosynthetic (or
semi-photosynthetic) shrub and herb species, they foster species diversity in
the forest. Some of the most exciting research has been conducted by Dr.
Suzanne Simard, forest ecologist at the University of British Columbia, who has
investigated how trees communicate. She found that trees use the fungal web to
purposely trade nutrients based on need, and not just between members of the
same species, but also between very different trees such as conifers and
flowering, broad-leaved trees. She has discovered that “mother trees” – older,
taller trees in the forest – are networked with all the other trees in that
part of the forest and act as hubs for the distribution of nutrients. You can
watch her discuss her research here:
https://www.ted.com/talks/suzanne_simard_how_trees_talk_to_each_other
http://www.ecology.com/2012/10/08/trees-communicate/
A Simard-like researcher is featured in the new Richard
Powers novel, “The Overstory,” which tells the story of a group of people who
all have passionate connections to trees.
We stopped to look at the Possum-haw Holly. Hollies are
dioecious, with female and male flowers occurring on separate plants. This
particular plant is male – we’ve seen it in flower in the spring and its
flowers have only stamens. Also, we’ve never seen it bearing fruit. Hollies can
often be spotted because of the presence of “short shoots.” All along the
typical long branches, there are short, stubby shoots that grow about a millimeter
a year–you can count the nodes (each representing a year’s growth) along the
shoot. A cluster of leaves and flowers is usually held at the tip of the short
shoot, and it’s believed that bringing the leaves and flowers into close
proximity speeds up the movement of carbohydrates to the rapidly growing
flowers and fruits. Short shoots are also thought to increase photosynthesis by
placing leaves at different places all throughout the crown of the shrub,
thereby capturing more of the sunshine throughout the day.
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|
| The sweet leaves of Horse-sugar |
We noticed that the patch of Horse-sugar (or Sweet-leaf)
seems to be expanding on both sides of the trail, presumably by the spread of
underground stems since no flowers or fruits have ever been seen on these
plants. Plants that grow in sunnier areas flower in early spring before new
leaves emerge. The leaves over-winter, though they often turn a deep burgundy
color before falling in the spring. Fresh leaves smell and taste like green
apples when crushed. The species name “tinctoria” refers to its use as a dye
plant–both leaves and bark yield a yellow dye.
We paused to think of Hugh and Carol Nourse, the first
leaders of our group, as we passed the large Persimmon tree, known as “Hugh’s
Persimmon,” that is downslope of the Purple Trail. Like the hollies, Persimmon
is also dioecious. This tree has never produced fruit so we assume it’s a male
tree, though no one has investigated the flowers which are held high in the
crown. The nearly black, blocky bark looks like charcoal briquettes.
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| Silverbell fruit, but what kind of Silverbell? |
Georgia has three species of Silverbell: Two-winged Silverbell, Carolina Silverbell, and
Four-winged Silverbell. The latter two species bear fruits that have four wings
and can be distinguished by their shape. Carolina Silverbell fruits are
broadest near the tip; Four-winged Silverbell fruits are broadest toward the
middle. You can decide from Don’s photo of the fruit which of these species we
saw today Young Silverbells are easy to recognize year-round by their bark
which has vertical gray and tan stripes. Older trees, seen mostly in the
mountains, have dark, almost grayish-purple bark but small branches in the
crown will have the same stripes.
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| Water Hemlock in the beaver marsh |
Water Hemlock (Cicuta
maculata) is flourishing in the beaver marsh. From a distance it looks like
Queen Anne’s Lace because it has the same type of inflorescence and dissected
leaves. Both Water Hemlock and Queen Anne’s Lace are in the same family, along
with many edible plants such as carrot, parsley, cumin, cilantro, dill, and
fennel. But Water Hemlock is extremely toxic to humans and other animals,
especially the roots, and eating even a tiny amount can be fatal or cause
permanent damage to the nervous system. Water Hemlock is related to Poison
Hemlock (Conium maculatum), a
European species believed to be the plant used to execute Socrates, and the two
look very similar.
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| Cranefly orchid flowers |
Crane-fly Orchids are in bud and flower along the Purple
Trail. A close look at the flowers reveals that they are slightly twisted
either to the right or left. The flowers are pollinated by noctuid moths that
probe the flowers for nectar and, in the process, bring their eyes into contact
with a sticky packet of pollen (called a pollinia). The packet sticks to either
the left or right eye of the moth, depending on which way the flower is
twisted, and is carried to another flower and deposited during nectar-probing
on the stigma of that flower. Dale described this type of pollination as “all
or nothing” – instead of producing lots of loose pollen grains that may be
picked up by several different visiting insects, all the pollen is packed
inside the pollinia and is carried all together to another flower – or not.
This may seem like a risky pollination strategy but the orchid family is the
second largest plant family, so they must be doing something right.
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| Walnut sphinx caterpillar A caterpillar that can “whistle.” |
A “Whistling”
Caterpillar? On the Purple Trail we discovered a sphinx moth (= hawk moth) caterpillar.
Most caterpillars in the sphinx family have a characteristic spine or horn
projecting from their posterior end. The other unique feature of this insect is
its pointed head. After passing it around we released it. Only later, when
comparing Don’s photograph with some references did I discover that it was a Walnut
Sphinx caterpillar, Amorpha juglandis.
But wait! There’s more! It turns out that this kind of caterpillar can whistle!
When attacked by a bird it emits a short sound, apparently to startle the
attacker. You
can download this short movie and play it on your computer to hear the
sound produced. It’s not spectacular, but, hey, it is a caterpillar!
The sound is produced when the caterpillar pulls its head
back towards its thorax, squeezing its abdomen. Each segment of the
caterpillars body has a pair of opening, called spiracles. These are the openings
of its respiratory system. When the body is contracted air is force out through
one of the last pairs of spiracles, producing the noise.
Reference: Bura, V.L., Rohwer, V.G., Martin, P.R., and Yack, J.E.
(2011). Whistling in caterpillars (Amorpha juglandis, Bombycoidea):
sound-producing mechanism and function. Journal of Experimental Biology 214,
30–37.
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| Newborn Red-bellied snake |
James found a newborn Red-bellied snake, Storeria occipitomaculata. This species
can be confused with the Brown snake, Storeria
dekayi, and the Ring-neck snake, Diadophis
punctatus. All these are small, secretive snakes that feed on
invertebrates. Both the Red-bellied and Brown snake are slug and snail
specialists, but also eat other small creepy-crawlies. The Storeria snakes both have keeled scales and give birth to their young.
Ring-neck has smooth scales and lays eggs. (Keeled scales have a ridge running
down their center, smooth scales lack a ridge.) The belly color is tan in the
Brown Snake, usually reddish orange in the Red-bellied and yellow with black
dots running down the middle in the Ring-neck.
SUMMARY OF OBSERVED SPECIES
|
Plants |
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Jimson |
Datura stramonium |
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Japanese |
Microstegium vimineum |
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Northern |
Quercus rubra |
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Cranefly |
Tipularia discolor |
|
Horse |
Symplocos tinctoria |
|
Possumhaw |
Ilex decidua |
|
Hophornbeam |
Ostrya virginiana |
|
Sourwood |
Oxydendrum arboreum |
|
Silverbell |
Halesia sp. |
|
American |
Carpinus caroliniana |
|
Water |
Cicuta maculata |
|
Animals |
|
|
Katydid |
Family |
|
Eastern |
Papilio glaucus |
|
Nine-banded |
Dasypus novemcinctus |
|
Camel |
Family |
|
Earthworm |
Annelida: |
|
Sphinx |
Family |
|
Wood |
Hylocichla mustelina |
|
Scarlet |
Piranga olivacea |
|
Red-bellied |
Storeria occipitomaculata |
|
Fungi (Mushrooms) |
|
|
Coral |
Ceratiomyxa fruticulosa |
|
Yellow |
Leucocoprinus bimbaumii |
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Chanterelle |
Cantharellus cibarius |
|
Gem-studded |
Lycoperdon perlatum |
|
Old |
Strobilomyces strobilaceus |
|
False |
Stereum ostrea |
|
Jellied |
Tremellodendron pallidum |
|
Wood |
Auricularia auricula |
|
Slime molds |
|
|
Coral |
Ceratiomyxa fruticulosa |