Friday, November 14, 2014

Ramble Report November 13 2014



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 reading: Bob Ambrose recited one of his new poetic creations, "The Ache at the Edge of Autumn." (Visit Bob's website to read more of his wonderful poems

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.
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? 

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
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
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)

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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.

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
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.

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
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
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.

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.

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.

Delicate fern moss

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.

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.
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.

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.
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

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