This week's report is written by Don Hunter with a few
additions by Dale. The photos are sample from a larger number that can be seen
on Don's
facebook album.
Here's the link to the "What a Plant Knows"
Coursera class . You can register for it for free. It has already finished but the video lectures will be available until Nov. 26. If
you register for the class you will be able to watch all the videos and read
the discussion forums. (You can also take the quizzes, but they will not be
"counted." Daniel Chamovits is the lecturer as
well as the author of the book What a
Plant Knows and I found him to be a good video lecturer.
“It was a cold and
frosty morn…..”
Kitty reading Emerson |
This morning it was 21 degrees at daybreak in the Athens
area and despite the frigid temps, we had twenty-one Ramblers show up for this,
the next to the last official Ramble for the 2013 season. Everyone was bundled up as they arrived at
the arbor and, after a few bits of information passed along by Hugh and Dale,
we had a nice reading provided by Kittie Everett, who read an excerpt from Ralph
Waldo Emerson’s essay Nature:
The
tempered light of the woods is like a perpetual morning, and is stimulating and
heroic. The anciently reported spells of these places creep on us. The stems of
pines, hemlocks, and oaks, almost gleam like iron on the excited eye. The
incommunicable trees begin to persuade us to live with them, and quit our life
of solemn trifles. Here no history, or church, or state, is interpolated on the
divine sky and the immortal year. How easily we might walk onward into the
opening landscape, absorbed by new pictures, and by thoughts fast succeeding
each other, until by degrees the recollection of home was crowded out of the
mind, all memory obliterated by the tyranny of the present, and we were led in
triumph by nature.
Following the reading, we headed down the paved path to the
Dunson Native Flora Garden, up the White Trail to the power line right-of-way
and into the forest, where we hooked up with the Blue Trail and walked it past
the first Torreya clearing, on to the second Torreya clearing and returned by
the same route.
frozen Witch Hazel flowers |
At the first stop, Dale showed us a blooming Witch Hazel
(Hamamelis virginiana). The petals were still frozen and crumpled, but when we passed by them two hours later they had recovered nicely. The witch-hazels are deciduous shrubs or (rarely) small
trees. They are popular ornamental
plants, grown for their clusters of rich yellow to orange-red flowers which
begin to expand in the autumn as or slightly before the leaves fall, and
continue blooming throughout the winter (Wikipedia). There were numerous, bright yellow flowers
adorning the example we saw. Earlier in
the week, the flowers were being heavily visited by flies that looked like
small yellow jackets, no doubt going about the business of pollination. Winter moths, which come out in November and
December and can be seen around porch lights at night, could be nocturnal
pollinators of these fall and winter blooming shrubs. If pollinated, these flowers will wait until
spring to develop their ovaries and seeds.
Silver Plume grass |
Right before we arrived at the power line right-of-way, we
stopped to look and several grasses.
Little Bluestem (Schizachyrium scoparium), characterized by its
alternating blue
or purple and green markings on the stem was our first stop
here. As we move further into winter,
the colored markings will turn brown.
Nearby we also saw River Oats (Chasmanthium latifolium) , Splitbeard
Bluestem (Andropogon ternarius) and Silver Plume (Saccharum alopecuroides) grasses. The Split Beard Bluestem is aptly named by
the twin tufts of remnant flowers at the ends of the grass stalks. The Silver Plume grass is a towering giant,
one of the tallest, if not the tallest, of the grasses seen along the Bot
Garden trails. We saw the occasional
panic grass (Panicum sp.) and the Dog Fennel (Eupatorium capillifolium) here
was also striking this morning, with its coating of frost and small ice
crystals.
Splitbeard Bluestem |
Redbud bud galls (closeup) |
Numerous bud galls visible against the sky |
Next, we saw a Redbud tree (Cercis canadensis) infested with
a large number of bud galls on its limbs and twigs.
These galls are the result of tiny mites laying their eggs in the terminal and lateral buds of the branches. When the
eggs hatch, the larvae eat the gall tissue. At this time of year, the mites are no longer
present, just the remaining gall. Just
how are the galls formed? Either
mechanical damage or salivary secretions introduced by the mites initiate
increased production of normal plant growth hormones. These plant hormones cause localized plant
growth that can result in increases in cell size (hypertrophy) and/or cell
number (hyperplasia). The outcome is an abnormal plant structure, the gall
(Wikipedia). Dale has been observing
this particular Redbud for 18 years.
Frost flowers at base of Verbesina virginica |
Moving on up the right-of-way, we were treated with what was
the first of many examples of “frost flowers”, probably the highlight of the
ramble. What initially appeared to be a
white plastic bag draped around the base of a plant was actually ice that had
been extruded from the stem. Several web sites have excellent descriptions of
this phenomenon: the Texas
Parks and Wildlife Department as well as this website. A nice
video, including some time-lapse shots of frost flowers forming on Verbesina virginica can be found here.
In the same locations as the frost flowers, we saw an
abundance of dried Bee Balm (Monarda sp.) seedheads, covered with frost and ice
crystals.
We walked back down the power line and turned into the forest on the White Trail and made
our way to the Blue Trail and immediately came upon one dead trees, a large
Northern Red Oak (Quercus rubra), the
upper trunk lying on the ground and the lower still standing, even though it is dead. Wood rotting fungi were abundant on both trunks.
Wood-rotting fungi on Northern Red Oak |
There are two general kinds of wood rotting fungi, named for
the color of the wood remaining after they have digested what they can: white
rots and brown rots. Woody tissue is made of plant cells. All plant cells are
surrounded by a cell wall made largely of cellulose (that's what paper is made
from). But cellulose alone is not very strong and in woody plants it is
strengthened by the addition of a substance called lignin. The combination of
cellulose and lignin enables trees to grow to tremendous heights and not be
crushed by their own weight. Cellulose is light colored and lignin is dark. The
fungi that rot wood digest either cellulose or lignin. Those that attack the
cellulose leave behind the dark colored lignin and are called "brown
rots." Those that digest lignin leave behind the light colored cellulose
and are called "white rots." (There are some fungi that can digest both cellulose
and lignin.) The only way to tell whether a particular fungus is a white or
brown rot is by looking it up in a book or examining the color of the wood
remaining after it has done its job.
Small Torreya behind Hugh |
Shortly, we passed by the first of two Torreya propagation sites adjacent to the Blue trail and walked
off-trail to take a closer look at one of the Florida Torreyas (Torreya taxifolia). This tree is also known as Gopher Wood,
Stinking Yew, or Stinking Cedar and is a rare and endangered species found in
northern Florida and southwest Georgia. The State Botanical Garden is
participating in a program to preserve this plant in the southeast U.S.
Continuing back on the Blue trail, we came upon a couple of
small Water Oaks (Quercus nigra),
where Dale pointed out the leaves on several of the trees. On a small sapling all the leaves were
unlobed and resembled the leaves of a Willow Oak. This seems to be a common
characteristic of young Water Oaks here in the Garden. On larger saplings some
of the leaves are developing shallow lobes that are more typical of a Water Oak.
We also saw two distinctly different leaves from the
Northern Red Oak, one from the shaded area of the tree, which was very broad, with
a lot of surface area to maximize it’s exposure to available sunlight, the
other from higher in the tree, which looked more typical of Northern Red Oaks,
being less broad, with deeper sinuses separating the sharp tipped lobes.
A little further down the Blue Trail, Hugh pointed out that
this area was a very good
example of an early succession forest, with many
large pines, both Loblolly (Pinus taeda)
and Shortleaf (Pinus echinata) and Black Cherry (Prunus serotina). There are
hardwood saplings present but they are far from mature. Hardwoods in this succession forest are
represented by maples and oaks (Water Oaks and Northern Red Oaks), as well as
American Beech (Fagus grandifolia). We saw a small Red Maple (Acer rubrum), easily identified by its toothed
leaf lobes and red petioles (leaf stems).
Red Maple leaves (note red petioles) |
Next we stopped at a small American
Beech tree, with its
colorful thin, papery leaves, with wavy leaf margins (remember, “beaches” have waves, when trying to identify this tree). Beech trees hold their leaves throughout the
winter and shed them in spring, right before the new leaves emerge from the
long and sharp pointed buds, which were pointed out by Dale at this stop.
Beech leaf |
Several trees retain their leaves throughout winter: Beech,
Hop Hornbeam, Chalk Maple and several of the Oaks. In addition to the beech
trees, chalk maple, hop hornbeam and
some of the oaks hold on to their leaves throughout much or most of the winter.
This retention of dead leaves is called marscence, a term that is useful in
impressing botanical nerds. Botanists know what causes leaves to fall in the
autumn, but they don't know why some trees retain the dead leaves until spring.
Some have suggested that when leaves are dropped in the fall any residual
nutrients they contain might be leached away when the roots are cold and cannot
effectively absorb them. By holding on to their leaves marscescent trees can
recover those nutrients when they become more physiologically active in the
spring. But this is not a very convincing argument and there is little data to
test it.
Here we saw one of the few examples of trail fauna we were
to see today. A Daddy (or Grandaddy) Longlegs,
also known as a harvestman (Phylum Arthropoda, Class Arachnida, Order
Opiliones) was seen working its way around a large Loblolly Pine tree. Dale allayed any fears harbored by Ramblers
with regard to toxicity or of these arachnids.
An urban legend claims that the harvestman is the most venomous animal
in the world, but the harvestman possesses fangs too short and a mouth too
round and small to bite a human and therefore is not dangerous (the same myth
applies to a similar looking spider, Pholcus
phalangioides, and the cranefly, which are both sometimes called a 'daddy
longlegs'). Furthermore, none of the known species of
harvestmen have venom glands; their chelicerae are not hollowed fangs but
grasping claws that are typically very small and definitely not strong enough
to break human skin. Even though most people would consider Harvestman spiders,
these are not real spiders, but bear a great resemblance to spiders given they
also have eight, sometimes very long, legs. (Wikipedia)
After popping out into the northwestern most of the two
Florida Torreya clearings, near
End view of Winged Sumac showing spiral leaf arrangement |
Winged Sumac showing alternate leaf arrangement |
At Donderos' |
At this point, we turned around and retraced our steps back
to the Visitor Center where a large group gathered at Donderos for refreshments
and great conversation.
SUMMARY OF SPECIES OBSERVED:
FLORA
Witch Hazel
(Hamamelis virginiana)
Little
Bluestem (Schizachyrium scoparium)
River Oats (Chasmanthium latifolium)
Splitbeard
Bluestem (Andropogon ternarius)
Silver Plume
(Saccharum alopecuroides)
Dog Fennel (Eupatorium capillifolium)
Redbud tree
(Cercis canadensis)
Frostweed or
White Crownbeard (Verbesinia virginica)
Bee Balm (Monarda sp.)
Northern Red
Oak (Quercus rubra)
Turkey Tail
mushrooms (Trametes versicolor)
Florida Torreya
(Torreya taxifolia)
Water Oak (Quercus nigra)
Loblolly
Pine (Pinus taeda)
Shortleaf Pine
(Pinus echinata)
Black Cherry
(Prunus serotina)
American
Beech (Fagus grandifolia)
Winged Sumac
(Rhus copallina)
FAUNA
Harvestman or Daddy Longlegs (Order Opiliones)