30 Ramblers appeared today for what started out as a the
coldest ramble of the season, but the chill was easily ignored as we saw many
fascinating things.
Click here
to see Don Hunter's photo album for today's ramble. (All the photos in this
blog are from Don's album.)
Today’s
route: Leaving the bus stop in the
upper parking lot we sauntered through the middle section of the parking lot
looking at trees, making our way over to the head of the Orange Trail. We went down the Orange Trail to the Hepatica
Bridge and took the Orange Trail spur up to the flower gardens and in to the
Visitor Center.
The parking lot would seem to be a poor place to experience
nature but the unmaintained strips that separate the asphalt parking areas have
lots of easily accessible trees and shrubs. Because they are exposed to more
light than those in the wooded areas they can retain their leaves longer. So we
took some time to look at the vegetation growing in these strips of land.
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| Ramblers, awed by the color of Sourwood & Tuliptree |
|
The most prominent saplings were decorated with radiant red
leaves, but they were strangely unfamiliar. The leaf shape hinted at Sourwood, but they were not as long as
those seen on the mature trees in the forest. They could have been Black Gum,
which also glows with red in the autumn, but the leaves are not eye-shaped
enough and they lacked to two "horns" that are often seen on Black
Gum. The most puzzling aspect was the bark -- where were the deep ridges that
is characteristic of Sourwood? As it turns out those ridges develop much later
in life; the young Sourwood has smooth bark! So how are we certain that it was
a Sourwood? We found an old inflorescence -- irrefutable proof -- no other tree
in our area has a similar cluster of flowers
Next to the Sourwood is a young sapling Tuliptree (AKA Yellow poplar, Tulip poplar). In the forest
Tuliptrees grow straight up, looking like giant cylindrical towers, but this
sapling was curved, leaning out towards the parking area where the light was
more intense, showing us that the form of the species in the woods is due to
the more even distribution of light.
There were two very large, white mushrooms emerging from the ground here. Unfortunately none of us
were able to identify them. The undersurface of the large cap had gills and
someone wanted to know where the spores were produced. Spores are produced from
the surface of the gills, always on the underside of the mushroom. This allows
the microscopic spores to drop downward where they are caught and transported
away by the gentlest of breezes. The gills greatly expand the spore-producing
surface, so a mushroom can produce literally, as Carl Sagan would say, "billions
and billions" spores.
One shrub still had green leaves and that should have been
the tip off, but we were all thinking of native plants and this didn't look
like any in the Garden that might be considered evergreen. Lili called us to
our senses -- it wasn't a native in the strict sense. It is native to the
coastal plain but does well here in the piedmont. As soon as Lili told us what
it was we found the confirmation, tiny, waxy berries attached to the twigs and
stems. You know what I'm talking about, don't you? Wax myrtle. (It used to be called Myrica cerifera, but is now is sometimes known as Morella cerifera.) The name derives from
the waxy berries. In colonial times they were gathered and boiled, the wax
floating to the top where it could be skimmed off and used to make candles.
Someone asked "Didn't it take an enormous number of berries to make a
candle?" Yes, it did. But what other choices did early colonists have?
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Hop hornbean leaf with some
doubly serrate teeth |
|
Young Hop hornbeams
grow here and you can see that their bark has not yet developed the flaky, cat
scratch appearance that is so characteristic of the mature tree. Scattered
among the Hop hornbeam saplings are a few Winged
elms. If you look carefully you can find the corky
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Winged Elm leaf with
triply serrate teeth |
|
ridges on a few of the
twigs and the remnants of those ridges also appear as irregular bumps on the
bark of the trunk. At this young age both species resemble one another but if
you look closely at the leaves you will see that the winged elm has triply
serrate edges while the hop hornbeam has single to doubly serrate margins.
While we were looking for the "wings" on the
winged elm Andie noticed that a Leaf-footed
bug had fallen on my jacket. It was so cold it could barely
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| Leaf-footed bug; mouth parts are held under the head. |
|
move, so we
could get a good look at it. The name derives from the large, leaf-like
expansions of it hind feet. No one knows the function of these structures, but
often exaggerated traits in animals are due to sexual selection. (Think of the
peacock's tail, or the antlers of deer, moose and elk.) Why don't we have the
answer to this question? Too many insects, not enough entomologists. If you
look carefully at Don's photo of this bug you can see one of the
characteristics that identifies a true bug: the piercing, sucking mouthpart. It
is a needle-like structure seen below the head and pointing backward. This
mouth part allows bugs to pierce through plant tissues and suck out their
juices. And some bug species are predatory, using this type of mouth part to
pierce the skin of other insects and suck out their body fluids(or blood in the
case of vertebrate victims)
.
Down on the Orange trail we stopped to look at an American Beech. One easily seen feature
identifies this tree: the long, pointed, cigar-shaped buds at the ends of the
twigs or the base of the leaves. The beech retains its leaves throughout winter
and makes a wonderful sight when the early morning sun makes them glow to life in
an otherwise drab, dormant forest. Other local species that retain their leaves
in winter are Hop hornbeam, the oaks and chalk maple, but only the Beech and Hop hornbeam produce a radiant
glow in the morning sun. (Look for this on the approach to the lower parking
lot when you come to the Garden during winter.)
The forest at the upper end of the Orange trail still has a
large number of Pine trees and many of the hardwoods are young and not yet tall
enough to reach the canopy. This is an early stage in forest succession. This area was in cultivation prior to the
creation of the State Botanical Garden. When the agricultural fields were left
undisturbed they were occupied by grasses and herbaceous plants. The first
trees to occupy the abandoned farm land were the pines and they became the
dominant canopy species. But pine seedlings do not thrive in shade and so the
hardwoods start to occupy the understory. As the pines die they will be
replaced by the young hardwoods that you see growing here now. The understory
plants are, at present, few and far between. This is undoubtedly due to the
heavy grazing by deer in the garden.
Some of the shrubs we see along the Orange trail are in the blueberry
family, Sparkleberry (also known as
Farkleberry) and High bush Blueberry.
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| Oyster mushrooms |
Don noticed a clump of Oyster mushrooms growing at the base
of a hickory tree.
And, as if we didn't already know it, we saw a reliable sign
of autumn: the first leaves of the Cranefly
Orchid, Tipularia. This unusual
plant produces a single accordion-pleated leaf, green on top and purple on the
bottom, in the
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| Tipularia leaves |
fall. The leaf will spend the winter taking advantage of the
sunlight that is no longer blocked by the leaves of the tree canopy overhead.
It is able, through photosynthesis, to manufacture sugar that is stored in its
underground corm. Come spring, the Tipularia leaf dies back and, in mid-summer,
a flowering stalk carrying a dozen or more blossoms appears, sans leaf. Sometimes the old spent flowering
stalk may be seen at this time of year next to the newly emerged leaf. (This website has pictures of
Tipularia flowers as well as some
natural history information.
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| Looking at Silver bell tree |
|
Further down the trail we were puzzled by a tree that we
should have known. It had simple, alternate leaves that were roughly round in
shape and had toothed margins. We all scratched our heads until someone had the
good sense to look higher up and saw the striped bark characteristic of the Silver bell. This individual was
growing in an atypically dry environment; normally Silver bell grows nearer to
streams or in riverine bottom lands.
We also noted the bark of mature Black cherry, which
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| Black Cherry bark |
|
Emily describes as looking like "smashed,
burnt potato chips."
All along many of the trails in the Garden you will find Christmas fern; it's the most common
fern in the Garden. The identifying feature is the shape of the leaflet
(pinnule in fern-speak) -- it looks like a Christmas stocking -- there is a
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| Christmas fern sporangia |
|
little toe projecting to the side at the base. When Christmas ferns produce
spores the terminal pinnules develop sporangia
on their under surfaces. These small structures house the developing spores and
release them when they mature. Like the spores of mushrooms, they are carried
away by air currents and, if they are lucky, will land in a favorable location
and ultimately produce a new fern. I've been curious to see when these fertile
fronds are produced and, so far, my impression is that you can find them in
every month of the year. (New Year's Resolution: record when fertile fronds are
seen.)
The Orange trail has two erosional features that grow larger with each passing year. One is
the intermittent channel that carries runoff and comes down from the left. The
other is the gully to the right, which is the origin of the Orange trail creek.
This gully is an example of headward erosion. It is caused by seepage of ground
water that emerges from its base. This ground water carries away soil as it
seeps out, causing the ground above to slump. Over time the very large gully
you see here has developed.
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| Southern Grape fern |
|
Further along, Avis, she of the ever sharp eyes, discovered
a Southern grape fern with fertile
frond. Avis amused herself and others by flicking the fertile frond and
producing a cloud of spores. But, unlike a Bic, after two flicks it was done.
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| Wooly galls on Water Oak |
|
Someone found an unusual structure on a Water oak leaf. It
is called a gall and is formed when,
in this case, an insect lays an egg in the midrib of the leaf. The plant reacts
by producing the abnormal growth that we see here in Don's photo. When the egg
inside hatches the larval insect feeds on the tissue of the gall and is
protected from many predators or parasites by the gall structure.
I originally thought this was a Wool sower gall, but, after
getting home and looking at my reference books, I've decided that it is a Wooly gall. Wool sower galls appear on
oak stems, are spherical and covered with pink and tan fuzz. The galls we found are on the leaf
mid-rib and are just tan in color. The Wooly gall is caused by a type of small
wasp.
The gall is made of plant tissues and is produced by the
reaction of the plant to either the presence of the egg, or something else that
the insect transmits with the egg when it is laid. The growth that results is
always typical of the species of insect that causes it. How these
species-specific growths are produced is one of the mysteries of galls. It is
known that many bacteria and fungi that can infect plants produce oddly shaped
growth responses, but these are usually amorphous and ill-formed. Gall
producing insects of one species cause repeatable, organized responses on the
part of the plant. You can identify the insect by the structure of the gall it
produces. No one, to my knowledge, knows how that precision of growth pattern
is produced. This website
has photos and information about the galls caused by a variety of different
organisms.
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| Delicate fern moss |
|
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| Delicate fern moss closeup |
|
Further down the trail we found a fallen, dead tree trunk on
which a large mat of Delicate fern moss
was growing. Someone asked if the mosses were decomposing the tree. The answer
is no. They may be getting some nutrients from the decomposing tree, but the
bulk of their nutrition comes from rainfall and dust. And, of course, they make
sugar from carbon dioxide in the air and water. From that sugar they manufacture
the cell walls that collectively make up the bodies of the moss. Those mosses
that grow on soil do derive some nutrients from the soil, but others that grow
on logs, tree trunks or rocks are just using the substrate for support. Here is a wonderful online resource for
moss ecology, but it presupposes a lot of background in biology.
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| Broad Beech fern |
|
Continuing along the trail we picked up leaves from the
ground and found those of Northern Red oak and Red maple. There was a Winged
elm with some of the corky wings visible against the sky high in the tree. The
usual vines were encountered: Climbing Hydrangia,
Poison Ivy and Muscadine grapes. Near streamside we see the Musclewood trees and somone found a Red mulberry. There were numerous Broad beech ferns, just beginning to senesce, and, on one of them,
a Daddy longlegs.
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| Daddy longlegs on Broad beech fern |
|
The Daddy longlegs (also known as Harvestmen) is not
an insect -- count the legs. All harvestmen have 8 legs, not 6 as in insects. Spiders also
have 8 legs, but Daddy longlegs aren't spiders either. There are many kinds of
Arthropods (animals with an exoskeleton and jointed legs): crustaceans,
insects, spiders, millipedes, centipedes and harvestmen, to name the most
common groups. Daddy longlegs, despite what you might have heard, are not
venomous. That is an urban legend. They feed on decaying vegetation and animal
matter. They have a segmented body, like all other arthropods, but it is not
divided into cleanly separate parts as in other arthropods. The little round
body rolls head, thorax and abdomen together, as you can see in Don's photo.
Also notice the two tiny eyes on top at the front; they look like a pair of
poppy seeds.
George turned over a rotting log and found a Southern two-lined salamander beneath
it. We placed it into a transparent box so everyone could examine it. The
southern Appalachians is the home of an explosive radiation of salamanders.
There are more species of lungless salamanders found there than anywhere else,
except possibly, tropical America. The lungless salamanders (plethodontids -- family
Plethodontidae) breath through the lining of the mouth and the surface of the
skin. Some are largely aquatic, inhabiting streams and stream sides throughout their
lives. Others are completely terrestrial, not even returning to water to
reproduce. Their eggs are laid in moist situations, as under logs, and develop
directly into adult salamanders. Others, like the Southern two-lined salamander, are
intermediate: the adults are terrestrial, but they return to the streams to lay
eggs that develop into aquatic larvae that later metamorphose into terrestrial
adults. Many plethodontids exhibit parental care, the female remaining with the
eggs until they hatch. If the parent salamander is removed the eggs disappear
or fail to hatch.
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| Sycamore fruits |
|
Jane found a Sycamore
fruit that was beginning to crumble apart, giving us an opportunity to see how
the Sycamore seeds form. Sycamore flowers are either male (stamens only) or
female (pistils only) and each tree has flowers of both sexes. The collection
of flowers, an inflorescence, is shaped like a small Tootsie Pop. All the
flowers, male or female, are clustered about a spherical central ball on a
stalk. Each female flower will produce a single seed, attached to the central
ball. Surrounding each seed is cluster of bristles that will dry out when the
fruit is ripe and fragment into fluffy flotation devices that will be wafted
away in the breeze, each carrying their seed to distant places. Some will fall
into a nearby river where they will float downstream until they are stranded on
a bar or bank where they can germinate. In the photo one of the Sycamore fruits
is already fragmenting and you can see the central "Tootsie Pop"
where the seeds were anchored.
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| Hepatica leaves |
|
For some of us Fall, while beautiful with its gaudy leafy
decoration, is an omen of the approaching winter. We look everywhere for some
positive sign and near the bridge we found it -- fresh leaves of Hepatica, newly emerged in preparation
for producing flowers early next spring. It's something to look forward to,
isn't it!
SUMMARY OF OBSERVED SPECIES:
Common Name
|
Scientific Name
|
Sourwood
|
Oxydendrum arboretum
|
Tulip tree
|
Liriodendron tulipifera
|
Large mushrooms
|
?
|
Hop hornbeam
|
Ostrya virginiana
|
Winged elm
|
Ulmus alata
|
Leaf-footed bug
|
Family Coreidae; Leptoglossus sp.
|
American beech
|
Fagus grandifolia
|
Sparkleberry
|
Vaccinium arboreum
|
Oyster mushroom
|
Pleurotus ostreatus
|
Crane fly orchid
|
Tipularia discolor
|
Silverbell tree
|
Halesia carolina
|
Black cherry
|
Prunus serotina
|
Christmas fern
|
Polystichum acrostichoides
|
Post oak
|
Quercus stellata
|
Southern grape fern
|
Botrychium biternatum
|
Wooly gall
|
Family Cynipidae?
|
Water oak
|
Quercus alba
|
Delicate fern moss
|
Thuidium delicatulum
|
Northern red oak
|
Quercus rubra
|
Climbing hydrangea
|
Decumaria barbara
|
Poison ivy
|
Toxicodendron radicans
|
Red maple
|
Acer rubrum
|
Muscadine
|
Vitis rotundifoflia
|
Musclewood
|
Carpinus caroliniana
|
bulbous shelf mushroom
|
|
Red mulberry
|
Morus rubra
|
Southern two-lined salamander
|
Eurycea cirrigera
|
Broad beech fern
|
Phegopteris hexagonoptera
|
Daddy longlegs
|
Order Opiliones
|
American sycamore
|
Platanus occidentalis
|
Chalk maple
|
Acer leucoderme
|
Round-lobed hepatica
|
Anemone americana
|
