Leader
for today’s Ramble: Heather

Authors
of today’s Ramble report: Linda, Heather, Don. Comments, edits, and suggestions
for the report can be sent to Linda at Lchafin@uga.edu.

Link to Don’s Facebook album for this Ramble. All
the photos that appear in this report, unless otherwise credited, were taken by
Don Hunter. Photos may be enlarged by clicking them with your mouse or tapping your screen.

Number
of Ramblers today: 21

Today’s
emphasis: Frost flowers and other frosty things in the prairie and floodplain

 

Announcements/Interesting Things
to Note:  

Bob Ambrose will give the featured presentation
at the next “Word of Mouth Open Mic,” Athens’s longest-running spoken word
event, on November 2nd, at The Globe in downtown Athens. The event starts at
7:00 with Bob’s presentation beginning at 7:30. The theme is “What Haunts the
End of the Anthropocene.” Bob writes: “I have prepared a set of nine poems
that address the effects of humankind on the living world, personified as Gaia.
Using biblical rhythms and modern scientific understanding, the set amounts to
a prophesy, or warning, of a future that could still be avoided.” Lists and links to the poems Bob will be reciting are on his webpage.

Richard extended an invitation to a garden walk and wood-fired
pizza oven dinner at his place on November 13^th at around 4:30 p.m.
He will send out details on the Facebook Nature Rambling group page.

The student farmer’s market at the UGarden continues every Thursday from 4:30-6 pm. All products are grown at the farm using organic practices, and all proceeds go to fund operations at the farm to provide fresh produce to families in need in the local community. 2510 South Milledge Ave., first driveway on the right (if you are coming from the Loop) after the Bot Garden entrance.

Today’s
Route: Hoping to catch the frost flowers before the sun topped the trees, we hurried down the entrance road to the right-of-way, and explored both north and south of the road, in the Nash Prairie, the new prairie, and the floodplain. We then took the long way home on the White Trail, walking upstream along the river to the Mimsie Lanier Center, then returning to the parking area along the entrance road.

Sun rising over the trees along the right-of-way prairie. Photo by Linda Chafin

Reading:

 

October 10 by Wendell Berry

Now constantly there is the sound,

quieter than rain,

of the leaves falling.

Under their loosening bright

gold, the sycamore limbs

bleach whiter.

Now the only flowers

are beeweed and aster, spray

of their white and lavender

over the brown leaves.

The calling of a crow sounds

Loud – landmark – now

that the life of summer falls

silent, and the nights grow.

-from “New Collected Poems,” Counterpoint, 2012.

Clasping Aster

OBSERVATIONS:

Frost
and ice crystals were on order for today’s ramble, so a little background on
these sometimes misunderstood words is called for. Frost forms when “water vapor
in an above-freezing
atmosphere
comes in contact with a solid surface whose temperature is below freezing,” per
Wikipedia. In other words, frost is not frozen dew, as I’ve always thought; it is
water vapor (a gas) that passes directly to ice (a solid), without ever going through
a liquid phase. Generally, frost forms on a surface only when that surface “is colder than
the surrounding air,” which accounts for why we may see lawns and fields covered
with frost when the air temperature is above 32 degrees, something that I’ve
long wondered about. This is especially true in low-lying areas because cold
air drains downslope and forms pools of colder temperature. As an example, during the
ramble we found frost flowers only on plants growing
on the lower slope of the right-of-way prairie.

A
term I was throwing around (probably inaccurately) on Thursday – rime – is defined as ice that “forms
when super-cooled water droplets freeze onto surfaces.…It is not a type of
frost, since usually water drops are involved [in rime formation]…
Unlike hoar
frost, which has a feathery appearance, rime generally has an icy, solid
appearance.” I’m not sure if the ice formations we saw on leaves and flowers
are frost or rime ice, or maybe some of both.

Another cold-weather phenomenon – frost flowers – has been a favorite of ramblers for years. Dale wrote
about frost flowers in a November 2015 nature ramble report. The
following is an excerpt from that report, though I recommend you read his
entire essay, here:

“How frost flowers form:
The
water in the soil enters the root system by a process called osmosis. Osmosis
is the term describing the movement of water across a cell membrane from a more
dilute solution to a more concentrated solution. In this case the more
concentrated solution is the sap in the root system and the less concentrated
solution is the water in the soil. This movement of water into the root causes
the sap in the plant’s conductive tissues to rise. If the stem above has
been injured or has a weakened skin the water will ooze out at the damaged
spots. When the temperature is low enough this oozing water will freeze,
beginning a frost flower. This 2013
article by James R.
Carter in the American Scientist magazine
is the best discussion I have found on how such lovely and delicate features
form. In his article, Carter also mentions a Georgia connection to the
phenomenon:

 ‘. . . physician and
naturalist John LeConte of the University of Georgia made many insightful
observations about whole and cut-off stems, both of which grew ice. He noted
that many plant stems were dead and dry at the time of year when he did his
study, although the roots might have been alive, but the ice formation
therefore didn’t seem to be connected to the plant’s physiological functions.
He observed, “At a distance they present an appearance resembling locks of
cotton-wool, varying from four to five inches in diameter, placed around the
roots of plants; and when numerous the effect is striking and beautiful.’

If
you want to see this phenomenon for yourself, wait until the overnight
temperatures are below freezing and go to the Bot Garden early (the grounds and
natural areas are open at 8 a.m.), before the sun is too high. It would be
interesting to see if the same plant can produce a frost flower more than once.
You could determine this by tying a marker to a specific plant and observing it
on successive days when the conditions are right.” (Thank you, Dale!)

We were dismayed to find the right-of-way newly shorn of
vegetation in many places. Georgia Power crudely trimmed the trees along
the forest edges and removed the Dogwoods in the Nash Prairie. They also
mowed the areas below the road that are dominated by White Crownbeard – the source of frost flowers –
so we didn’t see as many as expected. However, Don managed to capture
some wonderful images of this phenomenon – here’s a gallery of his frost flower photos from Thursday. Photos may be enlarged by clicking them with your mouse or tapping your screen.

Once we reached the floodplain, Heather alerted us to the icy spectacles to be seen at high
magnification – icy cubes, fans, and rods adorning the surfaces and margins of
leaves, petals, stems, thorns, and hairs of plants in the right-of-way. Below is a selection of her amazing macro photography. Photos may be enlarged by clicking them with your mouse or tapping your screen.

Don also captured the intricate beauty of ice and frost in the photographs below. Photos may be enlarged by clicking them with your mouse or tapping your screen.

Ground Ivy

Virgin’s Bower seed heads

Tall Goldenrod flower heads

Splitbeard Bluestem spikelets

Horseweed seed heads

Deer-tongue Witch-grass leaf sheaths

Common Wingstem leaf surfaces with galls

Carolina Horse–nettle thorns

Carolina Horse–nettle

As the sun rose above the
tree line, frost and ice turned to water, and we left the right-of-way and headed upstream along the Middle Oconee River on the White Trail, stopping first at the River Cane stand to examine two species of vines, one exotic and one native, twining through the thicket of cane stems.

Chinese Yam, an invasive exotic vine also called Cinnamon Vine, is in the yam family though not related to sweet potatoes (which are in the morning-glory family). It reproduces primarily by the spread of the pictured bulbils, which fall to the ground and sprout at the conspicuous “eyes,” similar to white potatoes (which are in the deadly nightshade family).

Fruits of Small White Morning-glory, a native climber

Several
species in the Aster/Composite family are still in flower along the White
Trail.

Fall is Purple Aster season in the Piedmont, from left to right: Clasping Aster, unknown Aster species, and Georgia Aster.

Several large Common (or Mountain) Silverbell trees occur in this stretch of the White Trail, including one that may be the record-sized tree for Clarke County.

Common Silverbell bark is distinctively striped on immature trees and branches (left, photo by Will Cook) and on purple-tinted mature trunks (right, photo by Don Hunter).

Gary provides scale for a large-diameter Common Silverbell.

Virginia Tiger Moth caterpillar, also known as Yellow Woolly-bear

Typically,
two generations of woolly caterpillars hatch from eggs during the summer, spin their cocoons, and
emerge as adult moths in a single year. A third generation may hatch in the
fall and overwinter as caterpillars, sheltering in wood piles or leaf litter.
Humans usually don’t notice these animals until they become conspicuous in the
fall while they are searching for shelter. They survive the winter by
producing a sugar-rich anti-freeze in their “blood” (actually hemolymph) that
reduces the freezing point of their bodily fluids. Next spring, these
caterpillars will leave their shelters, spin cocoons, and emerge in a couple of
weeks as Virginia Tiger Moths, ready to mate, lay eggs, and start the cycle all over
again.

Virginia Tiger Moth (photo by Andy Reago and Chrissy McClarren)

The white-fruited variety of the native American Beautyberry is apparently the result of a natural mutation and is now widely available in the nursery trade. Birds relish the magenta fruits of the species; it’s unknown if birds eat the white fruits of this variety.

Carolina Coralbead fruits

Carolina Coralbead twining up a pine sapling. It’s never too soon to start decorating for the holidays.

Pine Webworm Moth caterpillar nest made of frass and silk held on a branch of a young Loblolly Pine.

Pine Webworm Moth caterpillars build their nests at the tips of pine
branches; the nests are made of their own frass held together with silk webbing.
The nests are shared with other Pine Webworm Moth caterpillars, with all
tenants collecting and sharing pine needles with their roommates. Eventually,
the caterpillars crawl to the ground and form cocoons, where they overwinter, emerging
as adults in the spring. The caterpillars are not considered a serious threat
to pine trees.

OBSERVED SPECIES:

White Crownbeard     Verbesina virginica
Splitbeard Bluestem     Andropogon ternarius
Horseweed     Conyza canadensis syn. Erigeron canadensis
Common Wingstem     Verbesina alternifolia
Ground Ivy     Glechoma hederacea
Dotted Smartweed     Persicaria punctata
Deer-tongue Witch-grass     Dichanthelium clandestinum
Tall Goldenrod     Solidago altissima
Carolina Horse-nettle     Solanum carolinense
River Cane     Arundinaria gigantea
Small White Morning Glory     Ipomoea lacunosa
Chinese Yam, Cinnamon Vine     Dioscorea polystachya
Blue-stem Goldenrod     Solidago caesia
Curtis’s Goldenrod, Mountain Decumbent Goldenrod     Solidago curtisii
River Oats     Chasmanthium latifolium
Mock Orange     Philadelphus inodorus
Chinese Privet     Ligustrum sinense
Common Silverbell, Mountain Silverbell     Halesia tetraptera
River Birch     Betula nigra
Perilla Mint     Perilla frutescens
Virginia Tiger Moth     Spilosoma virginica
Virgin’s Bower    Clematis virginiana
Georgia Aster     Symphyotrichum georgianum
Clasping Aster, Late Purple Aster     Symphyotrichum patens
Michaux’s Sumac     Rhus michauxii
Smooth Sumac     Rhus glabra
American Beautyberry (white form)     Callicarpa americana var. lactea
Loblolly Pine     Pinus taeda
Carolina Coral-bead     Cocculus carolinus
Pine Webworm Moth (caterpillar nest)     Pococera rubustella

Postscript: Botanical gardens act
as artificial oases for butterflies in arid urban areas.

Postscript: Wait, why are there so few dead bugs
on my windshield these days?