Leader for today's Ramble: Dale
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.
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.
Number of Ramblers today: 15
Today's emphasis: Seeking what we find on the Purple Trail
Reading: Kathy Stege recited, from memory, Emily Dickinson's To Make a Prairie.
Today's Route: We made our way through the Herb & Physic Garden to the Pawpaw patch, hoping to see flower buds. From there we embarked on the Purple Trail but ran out of time before reaching the river, so we returned
Today's emphasis: Seeking what we find on the Purple Trail
Reading: Kathy Stege recited, from memory, Emily Dickinson's To Make a Prairie.
To make a prairie it takes a clover and one bee,
One clover, and a bee.
And revery.
The revery alone will do,
If bees are few.
One clover, and a bee.
And revery.
The revery alone will do,
If bees are few.
Today's Route: We made our way through the Herb & Physic Garden to the Pawpaw patch, hoping to see flower buds. From there we embarked on the Purple Trail but ran out of time before reaching the river, so we returned
OBSERVATIONS:
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| Pawpaw flower buds |
Pawpaw trees have not yet appeared, but the flower buds are swelling and some are beginning to open.
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| Poison Ivy vine on tree trunk |
Poison Ivy is easily recognized in summer by relying on the old ditty: "leaflets three, let it be." But winter presents a problem. All parts of the plant can cause dermatitis in sensitive individuals. That means you need to recognize the vine without its leaves. Fortunately, poison ivy vines are easily recognized. The vine climbs a tree by using numerous fibrous, hair-like rootlets that attach to the bark. You should avoid contact with the rootlets and vine -- all parts of the plant are capable of inducing a rash in sensitive individuals.
Signage: Throughout the Garden there are small aluminum signs that identify the nearby plants. Almost without exception these signs are vandalized, their borders scraped. The guilty party? Rodents, like squirrels or chipmunks. Unlike humans, rodent incisors continue to grow in length throughout their life. Continual usage wears the edges down, but sometimes they need a harder surface to keep the teeth from getting too long. If not maintained by constant wear the incisors would grow to long and the animal would starve to death.
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| Sap wells created by Yellow-bellied Sapsucker. |
Sapsucker wells We have visited this tree, a Hophornbeam, for many years. It's just one of its kind to be visited by a Yellow-bellied Sapsucker woodpecker, a winter visitor in these woods.
The Sapsucker finds a tree and begins to punch a shallow hole in its bark. When finished, the bird moves a short distance to the side of the first hole and repeats. Eventually it creates a ring of holes that ooze tree sap. The sapsucker sips the sap that oozes from the holes and, in addition, eats small insects that are attracted to the sugary fluid. Eventually the tree seals the holes and the bird moves up a short distance and makes a new series of wells.
Hop Hornbeam or Hophornbeam
This is a somewhat esoteric subject, so you might want to skip ahead to the next section.
This is a somewhat esoteric subject, so you might want to skip ahead to the next section.
Regardless of dictionaries, we have in entomology a rule for insect
common names that can be followed. It says: If the insect is what the
name implies, write the two words separately; otherwise run them
together. Thus we have such names as house fly, blow fly, and robber fly
contrasted with dragonfly, and butterfly, because the
latter are not flies, just as an aphislion is not a lion and a
silverfish is not a fish. The honey bee is an insect and is preeminently
a bee; “honeybee” is equivalent to “Johnsmith.”
From Anatomy of the Honey Bee by Robert E. Snodgrass
So as far as trees are concerned the question is: is the tree we call a hophorbeam a hornbeam?
In Europe the trees called hornbeams are in the genus Carpinus, in the Birch family. The common name, "hornbeam", refers to the use of their wood to yoke a team of oxen for plowing. Thus, the hophornbeam in the genus Ostrya is not a true hornbeam. The common name for Ostrya virginiana should be hophornbeam.
In Europe the trees called hornbeams are in the genus Carpinus, in the Birch family. The common name, "hornbeam", refers to the use of their wood to yoke a team of oxen for plowing. Thus, the hophornbeam in the genus Ostrya is not a true hornbeam. The common name for Ostrya virginiana should be hophornbeam.
Whether it should be hophornbeam or Hophornbean is a different matter.
Marcescence is a term that describes the retention of dead leaves by broad-leaved trees of the temperate zone. As autumn approaches most broad-leaved trees prepare for winter by shedding their leaves. (see Why trees drop their leaves for an explanation.)
As autumn approaches the chlorophyll and other substances are removed from the leaves for winter storage. At the same time the tree begins to seal off the leaf by creating a layer of cells called the abscission layer, to block the loss of water that would leak out of the tree. When the abscission layer is complete the leaf will eventually fall from the tree, breaking off at the abscission layer.
Except when it doesn't. Some trees retain all or man of their dead leaves throughout the winter. The phenomenon is called marcescence. The trees in our area are Oaks, Hophornbeam, American Hornbeam, Chalk Maple, American Beech. Some don't retain all their leaves, slowly losing them during winter. This time of year when you drive into the Bot Garden the marcescent Beech leaves are very pale and those of the Hophornbeam are a darker brown. The colors are more prominent after a rain.
Except when it doesn't. Some trees retain all or man of their dead leaves throughout the winter. The phenomenon is called marcescence. The trees in our area are Oaks, Hophornbeam, American Hornbeam, Chalk Maple, American Beech. Some don't retain all their leaves, slowly losing them during winter. This time of year when you drive into the Bot Garden the marcescent Beech leaves are very pale and those of the Hophornbeam are a darker brown. The colors are more prominent after a rain.
For a good summary of the possible adaptive significance of marcescence visit this page.
Lichens are composite organisms. They consist of a fungus (the mycobiont) and a photosynthetic unicellular organism (the photobiont). Reproduction can be sexual or asexual. If sexual, there is a problem: only the mycobiont reproduces. The resulting spores have no photobionts. They must acquire them from the environment, otherwise the mycobiont will perish. Asexual reproduction is accomplished by packaging both the myco- and photo- bionts in the same reproductive propagule.
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| Perforated Ruffle Lichen |
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| Script lichen closeup The black squiggles are the places where sexual reproduction occurs, producing spores that contain only the mycobiont. |
American Beech associates
The natural world is filled with interactions that occur so briefly that they are seldom seen. A hawk swoops in and plucks a bird from your bird feeder. You have to be there in the moment to experience that act of predation. Sometimes the interaction is more protracted or leaves evidence of having occurred. Like caterpillars eating the leaves of a plant. Today we saw evidence of such an interaction. We found a black, spongy mass on one of the small branches of an American Beech tree. Your first impression might have been that the fungus was eating the tree's leaves. But it is only growing ON the leaves, not consuming them.
If you visited the Beech tree during the summer you would find a colony of aphids on the branches above the one the fungus is growing on. The aphids are sucking sap from the tree. Tree sap has sugar in it but is a poor source of amino acids, the building blocks of proteins. To get enough amino acids the aphids have to suck a lot of sap. This gives them more sugar than they need and the excess is excreted. We call it "honeydew" and you know how sticky it is if you've parked your car beneath an aphid-infested tree.
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| Black Sooty Mold on branch of American Beech photo from Jan. 16, 2014, Ramble |
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| Closeup of Black Sooty Mold showing sponge-like texture. |
If you visited the Beech tree during the summer you would find a colony of aphids on the branches above the one the fungus is growing on. The aphids are sucking sap from the tree. Tree sap has sugar in it but is a poor source of amino acids, the building blocks of proteins. To get enough amino acids the aphids have to suck a lot of sap. This gives them more sugar than they need and the excess is excreted. We call it "honeydew" and you know how sticky it is if you've parked your car beneath an aphid-infested tree.
The aphid colony grows throughout the summer and more and more honeydew is dropped below the colony. Sooty Mold spores eventually drift into the sweet spot below the colony and begin to grow, feeding on the carbohydrate riches. Their food is aphid poo, not Beech trees.
We also found the remnants of a plant that is totally dependent on the Beech: Beech Drops. These flowering plants have become completely parasitic on Beeches -- they no longer have chlorophyll or leaves. Underground their roots have modified structures called haustoria that seek out Beech roots and fuse with them.
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| Beech Blight Aphids photo taken on a previous summer Ramble The aphids are covered with waxy secretions that protect them from predators. |
We also found the remnants of a plant that is totally dependent on the Beech: Beech Drops. These flowering plants have become completely parasitic on Beeches -- they no longer have chlorophyll or leaves. Underground their roots have modified structures called haustoria that seek out Beech roots and fuse with them.
Lacking chlorophyll means that the stems are no longer green. This makes them difficult to see against the background of fallen leaves. But if you get a search image in your mind you'll discover hundreds surrounding a single Beech.
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| Remains of last summer's Beech Drops |
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| Slimy Salamander body length approx. 2 inches |
Slimy Salamander
We discovered a small, black salamander under a piece of decaying wood. Its body was speckled with tiny white dots, a characteristic of the Slimy Salamander. If you handled it you would discover how appropriate the common name is. The skin secretions are extremely sticky and very irritating; you don't want to touch your mouth or eyes after handling one.
The Slimy Salamander is a member of the largest salamander family, the Plethodontidae. Plethodontids have two major centers of diversity: the southern Appalachians and Central and South America. New species continue to be discovered, especially in South America.
The most unusual feature of the family is the absence of lungs.They get their oxygen exclusively through their skin and the lining of the mouth and pharynx.
Although some plethodontids lay their eggs in ponds and streams most lay their eggs in moist areas under rocks or decaying wood. For these terrestrial breeding species there is no aquatic phase in their life cycle. In many species the female remains with her clutch of eggs until they hatch. Because of their high moisture requirements they are active mostly at night. In the daytime they seek the cover of moist leaf litter and beneath or in decaying wood.
Plethodontids are surprisingly abundant. According to one classic study, the total biomass of plethodontid salamanders in their study area exceeded the total biomass of all the resident birds and mammals in that area.
Plethodontids are surprisingly abundant. According to one classic study, the total biomass of plethodontid salamanders in their study area exceeded the total biomass of all the resident birds and mammals in that area.
Wood rotting fungi
Many pieces of fallen or cut wood support the growth of a variety of fungi. But we don't see the entire organism. What we see is called the fruiting body, the reproductive organ of a fungus. Hidden inside the wood is the body of the fungus. If out vision could penetrate the wood we would see, interlaced with the wood fibers, a dense network of delicate threads, intersecting, branching and twining about the wood cells they are digesting. It's like a plant whose only visible part is a flower. All the other parts, the stems, leaves, roots are invisible to us. What we see is the reproducive structure that doesn't make seeds -- it makes spores -- by the millions or billions.
The part hidden from our vision is the body of the fungus. It is called a mycelium and is made of cells that look like threads. The threads are called hyphae (singular: hypha). The hyphae elongate and branch, each hypha secreting a mixture of chemicals that will digest the wood cells it encounters.
Our only clue to how this hidden part of the fungus occupies its piece of wood is to look at the fruiting bodies it produces. Each species and each variety will produce a fruiting body that appears different and we can infer what part of a log is occupied by their myceliums.
What happens when a dead log is colonized by different kinds of fungi? Do they harmoniously share the log? Or do they actively secure their part of the wood? We can't observe directly what goes on, but we can infer part of the interaction. It appears that Robert Frost was right: "Good fences make good neighbors." As the mycelia explore the wood and come into contact they start walling off their domain. One of the ways this is done is by synthesis of a dark pigment called melanin. (Yes, melanin is what makes our skin and hair brown or black. It's really a class of compounds that have similar properties.)
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| There are at least two groups of fan-shaped fruiting bodies on this log. The gray-colored group on the top are Turkey Tails. The brown colored group below are Violet-toothed Polypores. |
What happens when a dead log is colonized by different kinds of fungi? Do they harmoniously share the log? Or do they actively secure their part of the wood? We can't observe directly what goes on, but we can infer part of the interaction. It appears that Robert Frost was right: "Good fences make good neighbors." As the mycelia explore the wood and come into contact they start walling off their domain. One of the ways this is done is by synthesis of a dark pigment called melanin. (Yes, melanin is what makes our skin and hair brown or black. It's really a class of compounds that have similar properties.)
The defensive secretion of melanin leaves a trace of where mycelia have met. Those pieces of wood are used by wood artisans to make specialty wood items like turned bowls or violins. Such wood is known as "spalted" and an example is seen below. The right side of the wood slice shows several areas delimited by heavy dark lines. Within each delimited area the different colors, light, pale tan, or darker brown reflect the different type of fungi that "own" the circumscribed area, In the lightest area the fungus was digesting the lignen, leaving behind the lighter colored cellulose.
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| Spalted 'beech cross section The heavy dark lines are the pigments produced by "warring" mycelia photo by M J Richardson via Wikipedia Commons. |
For more photographs of today's Ramble visit this page.
SUMMARY OF OBSERVED SPECIES:
Turkey Tail Fungus Trametes versicolor
Violet-toothed Polypore Trichaptum biforme
Carbon Balls Daldinia concentrica
Perforated Ruffle Lichen Parmotrema perforatum
Veitch's Winterhazel Corylopsis veitchiana
Pawpaw Asimina triloba
White Oak Quercus alba
Poison Ivy Toxicodendron radicans
American Beech Fagus grandifolia
Script lichen Graphis sp.
Changeable Mantleslug Megapallifera mutabilis
Yellow-bellied Sapsucker Sphyrapicus varius
Hophornbeam Ostrya virginiana
American Holly tree Ilex opaca
Speckled Blister Lichen Viridothelium virens
Elliott's Blueberry Vaccinium elliottii
Northern Red Oak Quercus rubra
False Turkey Tail fungus Stereum lobatum
Coral Pink Merulius Byssomerulius incarnatus
Hypoxylon Canker Biscogniauxia (Hypoxylon) atropunctatum
Slimy Salamander Plethodon glutinosus
Black Sooty Mold Scorias spongiosa
Beech Drops Epifagus virginiana
Ceramic Parchment Fungus Xylobolus frustulatus
