Leader for today’s Ramble: Linda
Link to Don’s Facebook album for this Ramble
Number of Ramblers today: 27
Today’s emphasis:  Trees and other vegetation on the flood plain
Reading:  Bob Ambrose read his poem, To Bring You Beauty.

I would bring you beauty
if I only knew how.
I would slip into spirit,

dissolve into autumn breeze
which carries the scent
of crimson sage

to clouds of yellow butterflies
in the afternoon light
of their lives.

As the press of obligation fades,
the busy pings, the urgent beeps,
and rumble of distant machines –

I hover with a bumblebee
in the spell of a purple aster.
I drift in scented air

on a lilting riff of mockingbird-song,
the swerve of a skipper,
a toddler’s giggle

through the elusive realm
where beauty infuses all being.
I would bring you a portion

but, reaching, it slips
through re-embodied hands
and recedes like time itself,

its lingering afterglow
reflected in clouds
of evening gnats.

 

Show and Tell:

Overcup Oak Acorns

Linda brought a short terminal branch from an Overcup Oak with leaves and several acorns. She fooled us all when she asked what oak group the Overcup belongs to, White or Red? Those brave enough to guess called out Red, but Linda corrected us by showing that the pointed lobes didn’t have bristle tips.

Ravenel’s Stinkhorn

Kathy Stege brought a stink horn fungus, pale in color and the upper third covered in dark slime that contains the fungal spores. (The technical term for the slime is “gleba.”) Stinkhorns attract flies with their odor. The flies eat the gleba, ingesting the fungal spores as well, and then fly off to other places. The spores pass through the fly’s digestive system unharmed.
For more information (and photos) check out this photo essay by a regular reader of this blog:
Stinkhorns: Fungi No One Can Love? by Dr. Robert Wyatt

Announcements/Interesting Things to Note:

        Emily reported that the minimum number of Nature Rambler t-shirts had been ordered, so if you were holding back, you can still place your order before the first of November. Two shades of blue, Navy and Sapphire, and several styles. You can either pickup your order or have it mailed to you for a small additional charge. Remember, the more you order the more the Garden will get to support the new Butterfly Trail.

Today’s Route:   We left the Pergola using the walkway beside the Children’s Garden comfort station heading over to the mulched path just below the Forest Play area.  This joins the White Trail Spur which we followed to the Orange Trail Spur, which we followed to the Middle Oconee River floodplain.  At the river, we turned left on the Orange Trail, going downriver to the beaver marsh boardwalk.  We returned back to the Purple Trail, taking it back to the Visitor Center.

OBSERVATIONS:

 

Ramblers paused on the Orange Trail above the river, to discuss the characteristic landforms of a many southeastern floodplains. Standing on the toe slope above the floodplain we could easily view the flooded slough, the river levee, and the river itself. Many Piedmont rivers are lined with low, sandy berms called levees. These form when the river repeatedly overflows its banks and soil carried in the floodwater is deposited on the floodplain. The heaviest and largest soil particles – sand – fall out first, forming sandy levees along the river’s bank. As the floodwaters continue to move across the land, finer soil particles – clay and silt – settle out, forming deep layers of fine-textured soil. Semi-permanently flooded areas called sloughs or back swamps form in the lowest areas of the floodplain. These are a distinctive feature here at the Garden. Gary told us about an old Native American term for a slough – a “yazoo” – for which the river and town (Yazoo City, Mississippi) are named (and also a national wildlife refuge in the Mississippi Delta).

Anyone interested in learning more about the ecology of southeastern river ecology, can read a great report written by Georgia’s own Charlie Wharton in 1982: http://npshistory.com/publications/usfws/biological-reports/81-37.pdf

Dr. Wharton also wrote a report on the natural communities of the Botanical Garden available here.

View of floodplain from Orange Spur Trail

Several species of flood-tolerant trees occur in abundance in the Middle Oconee River floodplain, including Tulip Tree, Sweet Gum, Red Maple, Green Ash, Box-elder, River Birch, and American Sycamore.  Most of these trees can also thrive in uplands but may be outcompeted by upland hardwoods such as oaks and hickories.

Trees in flooded habitats often have buttresses and swollen bases which increase stability and may help to aerate the root system. The top of the swollen area corresponds to the depth of the flooding.

Red Maple with burls all over its trunk. When cut, these burls make the much-prized bird’s-eye maple lumber.

Silverbell

Hop Hornbeam

Two understory trees that are often found on toe slopes above floodplains are Silverbell, with its distinctive striped bark, and Hop Hornbeam with rows of holes drilled by Yellow-belled Sapsuckers.

 

Large, female Joro spider on her web. Very small male directly above her.

Entering the floodplain, we encountered a large Joro spider female on her web. Directly above her was a very small male. This disparity in size between male and female spiders is especially common among the orb-weavers. In non-orbweavers the two sexes are more nearly the same size.  So why should sexual size disparity have evolved in the orb-weavers? There have been many hypotheses suggested, but, to date, none have been convincing enough to have answered the question. A good recent review, written for a general audience, is available here.

 

Green Ash leaf

Green Ash is abundant in the wetter part of the floodplain. Its leaves are opposite and composed of 5 – 9 leaflets and its twigs are a dull, gray-green.

While walking the trail on the toe slope, we happened upon two graduate students from the Warnell School of Forestry who were surveying Green Ash trees for an exotic and invasive beetle known as the Emerald Ash Borer. One of the students, Mitchell Green, explained that their goal is to help develop a plan to battle this insect which began devastating ash trees in Michigan in 2002 and has recently been found in Georgia. Currently, they plan to import a species of parasitoid wasp as a form of biocontrol. Woodpeckers also like the larval form of EAB and can be a source of natural control. For more info, see: https://www.aphis.usda.gov/publications/plant_health/faq_eab_biocontrol.pdf.

Emerald Ash Borers kill trees by laying their eggs in the bark; when the larvae emerge they bore into the ash trees and feed on the living tissues under the bark, disrupting the movement of water and nutrients throughout the tree. An infested tree dies within 2-4 years.

Emerald Ash Borer beetle

Tunnels made by EAB larvae feeding just under the bark.

Box-elders are abundant in the floodplain and can be easily identified year-round by the clusters of branches that emerge from the lower part of the trunk. These branches arise from dormant buds under the bark that are stimulated to sprout by some kind of stress, such as branch breakage. Young branches and twigs are bright green all year. During the summer, look for opposite, compound leaves, usually with 3 or 5 toothed leaflets. The three-leaflet leaves look a lot like Poison Ivy leaves. And just to complicate matters, sometimes Poison Ivy grows up a Box-elder tree! Look for Poison Ivy’s hairy stem to tell them apart.  

Poison Ivy growing at the base of Box Elder.

Clusters of paired samaras on Box Elder Note: the “wing” is not bilaterally symmetrical.

A single samara of Green Ash; the “wing” is more symmetrical than that of Box Elder.

Box-elder fruits are paired and winged, betraying the fact that it is actually a species of maple. Compared with the winged but much narrower fruit of Green Ash, which does not occur in pairs.

Red Mulberry leaves

Red Mulberry trees, another understory tree typical of bottomlands, are found in somewhat elevated parts of the floodplain where water does not stand for long stretches. Most Red Mulberry leaves are more or less heart-shaped and sandpapery to the touch. Some leaves may have a mitten-shape with one or two deep sinuses. In that case, it’s possible the tree is a hybrid with White Mulberry (Morus alba), a native of east Asia. White Mulberry, the tree that supports the silk moth, was brought to Georgia in 1733 by Oglethorpe as an effort to develop a non-cotton, slave-free agricultural alternative for the new colony. Sadly, Oglethorpe’s dream of a slave-free colony collapsed in less than a decade under pressure from farmers who saw their neighbors in South Carolina reaping the profits to be made in cotton cultivation by enslaved Africans. White Mulberry leaves are generally smooth and hairless, or only slightly rough to the touch, and usually have multiple lobes and sinuses.

A fallen River Birch

Fallen River Birch trunks are seen all along the levee and the adjacent Orange Trail. Typically found on levees, these trees have toppled as the riverbank erodes. The curling, papery bark is a distinctive indicator of this floodplain species.

Frosted Aster??

Small White Aster??

There are at least two species of fall-flowering white asters along the Orange Trail. They and two other common white asters are very hard to tell apart. Our best guess is that these are Small White Aster and possibly Frosted Aster. Kathy reported that these species make great garden plantings, becoming quite large and bushy under cultivation. And the flowers last a long time!

Cut-leaf Coneflower is still flowering though clearly on its way out.

Winged Elm is a bottomland tree and also an upland tree, quite happily thriving along interstate highways and upland ridges as well as in wetlands. The small, rounded oblong plates that make up its bark make some people think of tongue compressors.

Winged Elm leaves

Winged Elm bark

 

Pokeweed is still flowering and setting fruit even as older fruits are withering on nearby plants.

Climbing Hempweed

 Climbing Hempweed uses pokeweed and other vegetation as a natural trellis. Although a member of the composite family, this species lacks ray flowers, but its showy curved styles branches and mildly sweet scent call in the pollinators.

 

Sensitive Fern

Sensitive Fern has not yet succumbed to cooler night-time temperatures but will be one of the first to wither in the cold when it comes.

Tearthumb flowers

Tearthumb stem

Tearthumb flowers attest to their membership in the smartweed genus Persicaria, but nothing else in this genus (or in this habitat) has the sawtoothed stems that really will tear your thumb, not to mention hands and arms.

A super-large clump of Common Blue Violet dwarfs a smart phone. Take that, Big Tech!

Leaves of an American Sycamore tree growing near the riverbank.

Downy Lobelia

The sinewy trunk of a Musclewood tree, another member of the understory along riverbanks.

The old beaver marsh is lovely in the low light of autumn.

Rice Cutgrass dominates the grassy marsh. . .

. . .it too will leave your fingers in shreds if you rub your hand along the stiff hairs on its stem.

Japanese Beauty-berry

Japanese Beauty-berry, with its small leaves and berries, is planted elsewhere in the Garden and has escaped and become established at the edge of the marsh.

Duck Potato is common throughout the marsh.

A single plant of Buckthorn Bumelia, growing at the base of the Purple Trail.

As the trail turned upslope, typical upland species, such as Chalk Maple, began to appear.

Rusty Blackhaw

Rusty Blackhaw; Lower leaf surface midvein.

Rusty Blackhaw, another upland species, growing along the Purple Trail. Its name comes from the clumps of rust-colored hairs along the midvein on the lower surface of the leaves.

The V-shaped formation of migrating geese flying above the river is a harbinger of cooler weather.

SIGN OF THE TIMES.

Help!! I’m falling!

 

SUMMARY OF OBSERVED SPECIES:

Overcup Oak                        Quercus lyrata   

“Ravenel’s Stinkhorn”           Phallus ravenellii

Eastern Leaf-footed Bug      Leptoglossus phyllopus
American Beautyberry         Callicarpa americana
Tulip Tree                             Liriodendron tulipifera
Sweetgum Tree                    Liquidambar styraciflua
American Sycamore             Platanus occidentalis 

 Red Maple                           Acer rubrum
Winged Elm                          Ulmus alata
Mountain Silverbell               Halesia tetraptera
Hop hornbeam                      Ostrya virginiana
Joro Spider                           Trichonephila clavata
Box Elder                              Acer negundo
Poison Ivy                             Toxicodendron radicans
Red Mulberry                         Morus rubra
River Birch                             Betula nigra 

Small
White Aster                  Symphyotrichum racemosum

Frosted Aster                         Symphyotrichum pilosum
Dotted Smartweed                 Persicaria punctata
Green Ash                              Fraxinus pennsylvanica
Trumpet Vine                          Campsis radicans
Cut-leaf Coneflower                Rudbeckia laciniata
American Pokeweed               Phytolacca americana
Sensitive Fern                         Onoclea sensibilis
Climbing Hempweed               Mikania scandens
Tearthumb                               Persicaria sagittata 

Common Blue Violet               Viola sororia
Downy Lobelia                         Lobelia puberula
Chalk Maple                             Acer leucoderme
Duck Potato                             Sagittaria latifolia
Rice Cutgrass                          Leersia oryzoides
Beautyberry                             Callicarpa sp.
Buckthorn Bumelia                  Sideroxylon lycioides

Rusty Blackhaw                       Viburnum rufidulum

Leader for today’s Ramble: Dale
Number of Ramblers today:  32
Today’s emphasis:  Trees on the White Trail, old access road and Green Trail
Note: Don was unable to attend today’s Ramble, so there will be no Facebook album to document what we observed. Instead, I’ve used his photographs from past Rambles and photos sent to me by fellow ramblers. If there is no attribution for a photo, it was taken by Don Hunter.

Reading:  Bob Ambrose read an Emily Dickinson poem suggested by Sandy Shaul:

Two butterflies went out at Noon —

And waltzed upon a Farm —

Then stepped straight through the Firmament

And rested, on a Beam —

And then — together bore away

Upon a shining Sea —

Though never yet, in any Port —

Their coming, mentioned — be —

If spoken by the distant Bird —

If met in Ether Sea

By Frigate, or by Merchantman —

No notice — was — to me —

Announcements:

1. It is time to order your Nature Ramblers t-shirt! They need to be ordered before Nov. 1 (Last day to order is Oct. 31.)  Here is link for ordering.

http://natureramblers.satisfactoryprinting.com/nature_ramblers/shop/home 

All profits from the t- shirts will go to the Botanical Garden to support the new Butterfly Trail.

2. Please join the Friends of the Georgia Museum of Natural History. As UGA charts the future Museum’s future, your membership in the Friends is vital to demonstrate public support for the Museum and natural history. You can join online and pay through PayPal or with a credit card.

Once you join or if you are already a member, you are invited to an outdoor members only event on Sunday, October 24 from 4-6, On The Hill. RSVP at events@gmnhfriends.org.

3. Dan Williams will lead a Tree Ramble at Sandy Creek Nature Center on Wednesday, November 3rd at 9 AM. We will meet at the front of the Education and Visitors Center. Bring a mask and your enthusiasm!

Today’s Route:

Sidewalk
from the Pergola to mulched path through the Dunson Garden. Across paved
road on White Trail spur, across ROW to point inside the woods where
White, Green and Blue trails join. Then follow White Trail to access
road, take access road toward the river to the Green Trail crossing; the
Green Trail back to junction with White Trail.

 

OBSERVATIONS:

American Beech trees with smooth, gray bark		.

American Beech leaves with “wavy” edges.

American Beech terminal bud; shaped like a pointed cigar.

American Beech
   The first thing that strikes you about a Beech tree is its smooth, gray bark. (And, often, the declarations of love inscribed in that bark by adolescent boys with pocket knives.) There are other features that are unique to Beeches: Their elongate, pointed buds at the ends of each branch or at the base of most of the leaves. The leaves have wavy edges, each “wave” bearing a tiny prickle.
   A good mnemonic for remembering the leaf edge: “Where do you find waves? At the beach (Beech).”
Etymology
   Avis told us that the word Beech has the same root as the word Book, indicating that people have been writing on Beech trees since the dawn of time, or something like that.  Online Etymology Dictionary confirms it: “German Buch ‘book’ and Buche ‘beech’; see beech), the notion being of beechwood tablets on which runes were inscribed; but it may be from the tree itself (people still carve initials in them).” 
Smooth bark
   Trees have two sets of embryonic tissues called cambiums; the vascular cambium and the cork cambium. These are like stem cells in animals. When they divide either both daughter cells remain cambium cells or one remains a cambium cell but the other differentiates into a different specialized cell that is incapable of further cell division.
   The vascular cambium cells form a sheath that surrounds the entire tree, trunk, branches and twigs. It causes the tree to increase in diameter. The vascular cambium produces the cells that become the woody part of the tree, the xylem. Xylem tubes conduct water from the roots to the rest of the tree, branches, twigs, flowers, fruits and leaves. Each year the activity of the vascular cambium adds approximately 1/16 to 1/8 inch to the diameter of the trunk.
   Outside the layer of vascular cambium is a layer of different embryonic tissue, the cork cambium. This layer of cells produces the bark. The cells it produces on the outer surface pile up and die, becoming a layer of corky cells of variable thickness. (Wine corks are made from the bark of the Cork Oak.)
   If the cork cambium can keep pace with the vascular cambium the resulting bark is smooth and thin, like in the Beech. If it can’t keep up with the vascular cambium the bark is stretched and finally breaks apart. The bark pattern that is formed depends on the difference in reproductive rate of the two cambiums and the strength of connection between the dead cork cells in the bark, giving each tree species a different bark pattern.
Marcescence 

   Some young trees and lower limbs of older trees hang onto their dead leaves throughout the winter, a phenomenon called marcescence. Cells in the outer abscission layer do not completely break down (see image below from Linda’s winter tree class handout that shows the abscission zone). 

   Trees in our area that practice marcescence: American Beech, Oaks, Hop Hornbeam, Musclewood and Chalk Maple.

Abscission zone at base of leaf petiole. If the separation layer doesn’t break the leaf will hang on the tree until spring. (Illustration compliments of Linda Chafin.)

   This phenomenon is something of a puzzle. Why should a plant retain dead leaves over the winter? There are around a dozen hypotheses, none of which are clearly correct, or clearly wrong. This website has a summary of them.
   Jim told us that the retained leaves of Beech become paler and paler during winter, appearing to him as “ghosts of the forest.”
   For an explanation of why and how trees drop their leaves check out this Nature Rambling post.

Mockernut hickory 

Mockernut Hickory bark (photo by Susan Brown)

Left, Mockernut Hickory fruit; note thick husk and large nut. Right, Red/Pignut Hickory with smaller nut and thin husk.

   Mockernut hickory has very distinctive braided bark. The nut is surrounded by a very thick husk. Linda prepared a guide to identification of our local Hickories. It can be downloaded from this location: Hickories in the Georgia Piedmont.

   Gary Crider told us about boiling Mockernut nutmeats and finding them tasty as opposed to
the literature which says they are bitter. 

 

American Toad (not the one we saw today, but it has similar coloration). The swellings just behind the eyes are parotoid glands that contain a cocktail of toxic substances.

American Toad

   Someone discovered an American Toad near the base of the Mockernut Hickory. This was no mean feat. The toad had a reddish-brown coloration that perfectly matched the soil as well as the leaf litter. If it hadn’t moved we would have missed it.
Toads are famous for being warty, but they don’t cause warts if handled. There is a different reason to avoid rough handling. Behind the eyes, on the top of the head are a pair of swollen lumps, the parotoid glands. (Not to be confused with the parotid gland, which is a type of salivary gland in the mouth.) Parotoid glands secrete a very toxic, milky white fluid when the toad is roughly handled. (You may have heard of the death of dogs in Florida and Australia after attempting to eat a large species of toad, the Cane Toad, Rhinella marina (formerly Bufo marinus). Australian snakes and mammals have also died from attempts to eat Cane Toads.)
   If you’ve ever picked up a toad you probably got your hands wet when it emptied its bladder. This is probably worse for the toad than for you. Toads are in danger of dehydration and the loss of all that bladder water could endanger it. Gentle handling will not cause the release of the toxins from the parotoid gland. They have to come in contact with your mouth membranes to be absorbed. After handling a toad, wash your hand, just in case.
   Linda noticed the toad’s throat moving up and down and wanted to know if it was breathing. The short answer is yes, but the long answer is more interesting. When humans breath two groups of muscles are involved: the diaphragm and the rib muscles. When the rib muscles contract they pull the ribs upward. When the diaphragm contracts it drops downward. Both movements increase the volume of the thoracic cavity, lowering the pressure on the lungs. This lowered pressure draws air into the lungs. When the diaphragm and rib muscles relax they return to their resting position, which squeezes the lungs, expelling the air. You probably remember this from grade school. Frogs and toads can’t breathe this way – they don’t have ribs and they don’t have a diaphragm. So how do they breathe?

   Breathing begins with getting oxygen into the blood. In humans the lungs are where this happens. In frogs and toads there are three places where oxygen enters the circulatory system: lungs, skin, and the the lining of the mouth. All these locations bring numerous fine blood vessels (capillaries) into close contact with a moist surface exposed to air. It is there that oxygen diffuses into the red blood cells of the circulatory system. 

   Of the three sites in frogs and toads, oxygen absorption at the skin continues constantly. 

   The other two locations, mouth and lungs involve some other structures: the nostrils and the glottis.The glottis is a valve in the esophagus that opens to allow air to pass into and out of the lungs. The glottis sits atop the larynx in frogs and toads as it does in humans. (At one time or another we’ve all had food go down the wrong way. That was a failure of the epiglottis, a flap that keeps food from getting into the lungs — when it works properly.) In frogs and toads the glottis just opens or closes, there is no epiglottis.

   Frogs and toads can open and close their nostrils. You and I can’t.

   We’re ready to find out how frogs and toads breathe.

   Mouth respiration, which Linda observed, occurs when the nostrils are open, the glottis is closed and the floor of the mouth is pulled down by muscles, enlarging the mouth cavity and lowering the air pressure in the mouth.  This draws air in through the open nostrils and mouth capillaries pick up the oxygen in the fresh air that enters the mouth. This mouth breathing is what Linda noticed — the toad’s “throat” was fluttering rapidly up and down.

   How does air get into the lungs? First, nostrils open, glottis closed, mouth floor drops further than when just mouth breathing. Then the nostrils close and the glottis opens as the floor of the mouth rises. The air can’t get out through the closed nostrils so it gets pushed into the lungs through the open glottis. Reversing this process moves air out of the lungs into the mouth. Then the glottis is closed and the nostrils open. When the floor of the mouth moves up it pushes the stale air out the nostrils. What moves the air out of the lungs? The lungs are elastic bags with a few muscles. When the lungs are filled and the glottis opens the lungs relax, expelling some of the air into the mouth cavity. Like a partially inflated balloon expells air when it’s opened.

White Oaks or Red Oaks
   The Oaks in our area fall into two groups: the Red Oak group and the White Oak group. Here are some of the differences:
 

Comparison of White Oak and Red Oak leaves. Left: White Oak leaf; note rounded lobes. Right: Red Oak leaf; note pointed, bristle=tipped lobes.

White Oak group:
        Leaf lobes: rounded, no bristle tip
        Acorns mature in their first year
        Acorns germinate in fall of first year
        Acorns have lower tannin content
Red Oak group:
        Leaf lobes: pointed, with a bristle tip
        Acorns mature in their second year on tree
        Acorns germinate in spring of following year
        Acorns have higher tannin content

Tannins are bitter tasting compounds. If you’ve ever tasted a persimmon before it’s ripe you know how it “puckers” your mouth. That was tannin that did that. When squirrels are preparing for winter they gather acorns and bury them for later retrieval and consumption. But squirrels frequently eat White Oak acorns, instead of being buried. When they are buried, the squirrel will often bite off the bottom end of the acorn, where the plant embryo is located, thus preventing the acorn from germinating. Red oak acorns are buried intact.
   Jim told us about another difference between the Red and White Oak groups. The water conducting cells of trees, the xylem, are replaced every year. The older cells are dead and, in the White Oak group, are filled with balloon-like structures called tyloses. Red Oak xylem tubes remain unfilled. If you take a piece of Red Oak wood and put your lips to one end, you can blow cigarette smoke out the other end. This stunt fails with White Oak wood.

White Oak leaf; note the rounded lobe tips and lack of bristles		.

   Linda told us about the outbreak of Black-dotted Brown Moth on White Oaks in Athens 10 years ago.
The affected trees lost their characteristic pale gray bark because
birds were flicking the the loose plates off the trunks to get at the
millions of caterpillars that were hiding under the bark. Fellow Ramblers
talked about how people coated the trunks of oak trees in their yards
with Crisco shortening to deter the caterpillars. Also download this pdf file about the Black Dotted Brown Moth.

 

Comparison of Red oak group leaves From Left to Right: Southern Red Oak (sun leaf) Southern Red Oak (shade leaf) Scarlet Oak Northern Red Oak

Northern Red Oak is one of the commonest oaks in the garden. The trunk has “ski trails.” The ridges of bark are smooth and reflect light, giving the impression of ski tracks going up and down the trunk. The leaves are broad with shallow sinuses and each lobe end in a sharp point.

Southern Red Oak is found in dry, upland sites. The leaf undersurface is white, due to the density of white hairs that reflect the light and slows moisture loss. Leaves are thick and hang perpendicular to ground and parallel to sun. They are also more variable in shape, ranging from elongate with slightly curved main vein, like the blade of a scythe, to a bell shaped (rounded) leaf base and a prominent “clapper.”  The bell shape of the shade leaves provides another mnemonic: bell-shaped leaf base = Southern Bell(e) = Southern Red Oak. The trunk lacks the “ski trails” of the Northern Red Oak.

White ash 

Linda pulled out her pocket knife and sliced off a think sliver of bark to show us the inner bark color orangey-tan. White ash grows in more upland sites while Green Ash grows in moister situations, like flood plains and stream banks. They can told apart by details like the location of the lateral bud relative to the leaf scar or the shape of the samara with its seed.

Sun leaf vs shade leaf
   Leaves, even on the same tree, vary a lot. The position of the leaf on the tree makes a difference in its structure. Leaves low on the tree or on the north side get less sunlight than leaves at the top or on the south side. As a rule of thumb: the more light received, the smaller, thicker and darker green a leaf is. Less light: leaves are larger, thinner and paler green. These differences are adaptive. Leaves exposed to higher winds need to be smaller to reduce water loss. At the same time, on the top of a tree, they can pack in extra layers of green, photosynthetic cells to capture more of the intense light. Leaves in the shade are not exposed to high winds and can have a larger surface area to capture the attenuated sunlight.

Burls distort the trunk of a tree.

Burls were seen on several trees (the photo is from a previous ramble). They are woody, rounded masses on the trunks and roots of trees caused by a pathogen – bacteria, fungi, or virus that has invaded the live tissue beneath the bark. The pathogen releases chemicals that stimulate the production of tumor-like tissue. This tissue isolates and contains the invader so that the damage is limited to the burl. Burls are usually not fatal and will continue to grow with the tree, laying down annual rings like the rest of the tree. Burls are much sought after by wood turners, who turn the crazy growth pattern of burl cells into works of art.

Scarlet oak 

Scarlet Oak leaf Note the very deep sinuses (the space between the leaf lobes.) My finger and thumb are inserted in the first pair of sinuses.

   Scarlet Oak is a member of the Red Oak group. It’s leaves are lobed, with bristle points at the end of lobe. The sinuses (the space between adjacent lobes) are much deeper than those of Northern Red Oak. Like the Northern Red, the Scarlet Oak has “ski trails” on the bark. Some people think they are narrower, but I’ve never been able to confince myselt that’s true. The acorns have a faint ring around the end opposite the cap.  

Part 1; End of a Scarlet Oak shoot. The other end is seen in the photo below. Both photos were taken by Susan Brown.

Part 2; Scarlet Oak shoot This is the end of the shoot that was closest to the tree.

We found a complete current year shoot of a Scarlet Oak that recently broken from the tree. Part 1, above, shows the end of the shoot furthest from the tree; Part 2 shows the part of the shoot closest to the tree. My finger and thumb are holding the branch by last year’s growth (2020). Moving along the branch, away from the tree end, you can see a change in texture of the shoot. It is a different shade of brown and is glossier. That marks the beginning of this year’s growth. Everything to the left of that mark appeared in 2021, including the unique parts shown in Part 1.

   Moving to Part 1. The gray objects you see at the base of most of the leaves are axillary buds, so called because they are in the “arm pit” of the leaf petiole. (Axilla is the anatomical name for human arm pit.) Axillary buds will usually give rise to leaves the following year.

   Still in Part 1. At the very end of the branch you’ll see a much larger bud. This is the terminal bud of the branch. Next spring it will give rise to a new shoot (branch) like the one we’re looking at right now. (Or, it would if it were still connected to the tree.) If you coulc look into the terminal bud right now you would find next year’s shoot in miniature — every tiny leaf in microscopic miniature.
   The next paragraph explains this more lucidly than I can, so you should read it, especially if I confused you.
Shoot Growth in trees:

“Within the bud, two growth habits are possible, fixed growth and free growth. Fixed growth occurs in species such as pines, hickory, and oaks, where the buds contain a preformed shoot. All of the components of next year’s shoot are contained in the bud formed this year; the number of leaves and nodes is predetermined by this year’s environmental conditions. The length between leaves and nodes is influenced by the environmental conditions the tree encounters next year. 

Free growth, in species such as cottonwood, willow, and silver maple, occurs when buds contain shoots with some preformed leaves, but which are also capable of forming additional leaves. These species can continue to grow as long as environmental conditions are favorable.”

Source.

Shagbark Hickory bark plates are loose at top and bottom.

Shagbark hickory

   Three Shagbark Hickories
grow in the shallow ravine between the Green and Blue trails. Their
shagginess is due to their bark’s vertical plates turning loose at
both top and bottom and curling away from the trunk. White
Oak bark is also shaggy, but its

bark plates loosen along the side, not the top and bottom.

   Shagbark nuts are much smaller that Mockernuts and have a
very thin husk compared to Mocckernuts thick husk. 

   Shagbark occurs in this
ravine because the soil there likely has a higher pH due to a band of
amphibolite that angles across the Garden from the nearby ridgeline all
the way to the river. Amphibolite is high in calcium and magnesium which
raises the pH of soils that develop over it. Calcium-loving plants
(calciphiles) such as Shagbark Hickory are often found over amphibolite
bedrock.

 

Blowdowns

   There are a large number of “blowdowns” along the trails in the Botanical Garden. These are due to a large number of factors, but a prominant one is 19th century agricultural practices. They stripped the topsoil from the hills and now oak trees are only shallowly rooted, making them vulnerable to windthrow.

   Windthrown trees create “tip ups,” the term applied to the turned up root mass of the tree. The space occupied by the roots is now a pit and the soil adhering to the roots is a new microenvironment. The forest may have lost a tree, but it gained new habitat that can be utilized by a variety of plants and animals.

SUMMARY OF OBSERVED SPECIES:

 
Mockernut Hickory    Carya tomentosa
Southern Red Oak    Quercus falcata
Scarlet Oak               Quercus coccinea
Northern Red Oak     Quercus rubra
American Beech        Fagus grandifolia
American Toad          Bufo (Anaxyrus) americanus

 

Leader for today’s Ramble: Linda
Link to Don’s Facebook album for this Ramble. All the photos in this post are compliments of Don Hunter, unless otherwise credited.

Number of Ramblers today: 30
Today’s emphasis: Learning to identify grasses
Reading:
Linda read the entry for September 23 from An Almanac for Moderns, by Donald Culross Peattie:

   How much of any landscape is due to the grasses is a quality in scenery that the best descriptions rarely admit. Orchard grass lends to any land that it inhabits something ample and light and gay. To the marshes the reed, Phragmites, gives long slant rainy-looking lines, and from their grasses the pampas and the steppes must surely take full half of their contour.
   It is in autumn that the grasses hereabout come forth in their full beauty; they fill the meadows like some fluid till they are become wind-swirled living lakes. But above all they give the meadow scene its dominant color. There is not one of our sterile upland fields or abandoned farms where the beard grass, Andropogon, does not show its soft terra-cotta sheaths, its glaucous blue stems, and woolly gray puffs of downy seed half bursting from the spike. The misnamed redtop troops across the fields, its purplish stems standing rank to rank, the panicles turning a dull gold as the seeds fall, reflecting the mild sunlight of hazy Indian summer mornings. In the woods and old fields the Indian grass has begun to bloom-as enchanting as any flower that, can boast calyx and corolla, with its golden brown spikelets, its dangling orange anthers, the whole plant turning to a sun-burnished bronze in its old age.

 

Sandra and her sisters made a surprise appearencel

Special Visitors:  Sandra Hoffberg, a former Nature Rambler who is a post-doctoral researcher at Columbia University, paid us a surprise visit this morning. Sandra received her Ph.D. from UGA in 2017, studying invasive species like Wisteria and Kudzu. She continues to work on invasive plants, this time on amaranths, at Columbia.  Her last Ramble with us was on July 20, 2017, so we were surprised and delighted to see her today.

Show and Tell:

The first of Halley’s Georgia Asters to bloom this year.

Halley brought some “first of season” Georgia Asters from her yard

Today’s Route:   We left the arbor and headed into the Lower Shade Garden via the sidewalk nearest to the Visitor Center.  We exited the Shade Garden and headed up the White Trail Spur connecting the paved road and the ROW.  We worked our way up the ROW via the two-rut road for a bit then turned around and headed all the way down the ROW to the paved road.  Once we were at the road, we took a left and headed back to the Visitor Center via the road, stopping briefly at the Passionflower vines on the Dunson Garden deer fence.

OBSERVATIONS:

Arbor:

This Joro on its web is illuminated to show the arrangement of the capture threads.

Don is trying to understand how the Joro webs are built. Here’s what he thinks, so far:

1. First, a wide, square or rectilinear based grid of silk threads is laid down.  It is on this silk framework that the sticky capture thread is attached. As the spider walks across the framwork she keeps a constant distance from the center of the web so the capture thread is laid in a circle, or would be, if the spider completly walked around the web.
   
2. Insterd, she only walks about 3/4 of the way and then reverses her path but lays the silk a short distance outside the first line she just finished producing.
3. She continues this pattern, reversing her direction four or five times, after which she begins to lay another set of silk threads, but starting just a little fit further outside the previous group. (Look at the photo above and pick one thread. Follow it and you will find where she doubled back on her path. You may be able to find more reversals or other variations in the silk patterns.
   
4. In many of the webs, the upper quarter lacks capture threads due to the spider reversing her direction.
5. In addition to the two dimensional capture orb there are chaoticly organized, three-dimensional strands of silk that surround the area within which the orb is located.  Don say’s he doesn’t yet know how and/or when these messy strands of silk fit into the construction of the capture web proper.
   

Heather found a tiny Keeled Treehopper on goldenrod.

 

 

You can barely see the spindly legs of this Daddy Long Legs hiding in the Rattlesnake Master seed heads.

 

Yellow Garden Spider waiting on its web for an insect to blunder into the web. The dense, white zig-zag is the stabilimentum.

Lower Shade Garden:

Just before leaving the Lower Shade Garden, Halley pointed out a single Jackson’s Slender Caesar mushroom, an amanita, popping out of the duff.

 

White Trail Spur (paved road to ROW):

Linda wrote at beginner’s guide to identifying grasses for Tipularia-Journal of the Georgia Botanical Society in 2014. It’s available for downloading as a pdf file here.
With that guide in hand this report will not repeat all the things Linda told us about grasses today. Grasses not mentioned in the article are shown and discussed below.

 

Bowl and Doily spider web made visible by dew.

Because of the heavy dew this morning, spider webs were especially prominent.

 

Big Top Love Grass

.

Big Top Love Grass and its close relative Purple Love Grass are especially noticeable on dewy mornings.
    

Eastern Fork-tailed Damselfly, chilled and hanging from Purple Top Grass seeds. (Damselflies don’t eat seeds; they eat other flying insects.)

An immature  insect on Purple Top Grass seeds.

 

 

Northern Yellow Sac Spider ??

Split-beard Bluestem

Split-beard Bluestem stems are red and the leaf sheaths are blue-green, creating a two-tone barber-pole effect.

Split-beard Bluestem with “split” seed head

Rabbit Tobacco

Rabbit Tobacco is scattered over much of the ROW. The flower heads are barely open even at maturity.

Horseweed

Horseweed stem and leaves

Horseweed flowers

Horseweed flower heads as open as they will ever be.

One Horseweed plant had very hairy stems and lower leaves. Another nearby one was hardly hairy at all. This species frequently shows up in recently disturbed ground.

Beaked Panicgrass with its pointed (“beaked”) seed heads

Saw Greenbrier is common in open sunny areas.

 

Grasshopper with “Summit disease”

Infected grasshopper closeup The white encrustations are fungal spore-producing structures.

Heather found two examples from a grasshopper horror movie. The grasshoppers were dead but clinging tightly to the stems of grasses, head upward, as if the they had been trying to reach the top. This is the symptom of “summit disease,” in which grasshoppers infected by a fungus (Entomophaga grylii) climb up a grass stem or other vertical vegetation and die, tightly gripping the stem. The fungus emerges through the thin cuticle between the body segments and leg joints, dispersing its spores. Visit this website for more details.

 

Blue Mistflower in the Nash Prairie

A low hairy ligule and patch of long hairs mark the transition from the leaf blade to leaf sheath of Silver Plume Grass

Stand of Silver Plume Grass at the edge of the woods..

Mature Thimbleweed seed head in the Nash Prairie

Decomposing Thimbleweed leaves

Maturing Thimbleweed seed pods

 

Brilliant Jumping Spider hunting on Rabbit Tobacco

 

”       Linda….share the wire grass story… I missed most of it.  

Dog Fennel; a natural bug repellent?!

Roger, who grew up in south Georgia, told that when he was working outside he would grab a handful of Dog Fennel and put it behind his ears as a bug repellent. 

 

Clasping Aster in the Nash Prairie

Maryland Goldenaster in the Nash Prairie

Yellow Indian Grass in the restored prairie

Coral Bead twining on Dog Fennel

Blazing Star in the Nash Prairie

Lined Orbweaver?

Hibiscus Scentless Plant Bug nymph

While we were examining the Passionflower vines on the Dunson Garden deer fence, Richard noticed that many of the brown, dried hibiscus seed capsules were teeming with Hibiscus Scentless Plant Bug nymphs, some early stage, barely visible red dots, but most mid- to late stage but still wingless.

SUMMARY OF OBSERVED SPECIES:

Joro Spider     Trichonephila clavata
Spinyback Orbweaver     Gasteracantha cancriformis
Keeled Treehopper     Entylia carinata
Goldenrod     Solidago sp.
Daddy Longlegs/Harvestmen     Arachnida: Opiliones
Rattlesnake Master      Eryngium yuccifolium
Yellow Garden Spider     Argiope aurantia
Jackson’s Slender Caesar mushroom     Amanita jacksonii
River Oats     Chasmanthium latifolium
Bowl and Doily spider     Frontinella pyramitela
Big Top Lovegrass     Eragrostis hirsuta
Purple Top Grass/Grease Grass     Tridens flavus
Eastern Forktail damselfly     Ischnura verticalis
Northern Yellow Sac Spider (tentative)     Cheiracanthium mildei ?
Splitbeard Bluestem grass     Andropogon ternarius
Rabbit Tobacco    Pseudognaphalium  obtusifolium
Horseweed     Conyza canadensis
Beaked Panicgrass     Panicum anceps
Saw Greenbrier     Smilax bona-nox
Grasshopper (no ID)     Order Orthoptera
Blue Mistflower     Conoclinium coelestinum
Silver Plume Grass     Saccharum alopecuroides
Thimbleweed     Anemone virginiana
Brilliant Jumping Spider     Phidippus clarus
Dog Fennel     Eupatorium capillifolium
Maryland Goldenaster     Chrysopsis mariana
Clasping Aster     Symphyotrichum patens
Purple Fountain Grass     Pennisetum setaceum rubrum
Fescue     Festuca sp.
Yellow Indian Grass     Sorghastrum nutans
Carolina Moonseed AKA Coral Bead Vine     Cocculus carolinus
Dense Blazing Star     Liatris spicata
Lined Orbweaver     Mangora gibberosa
Passionflower Vine     Passiflora incarnata
Hibiscus Scentless Plant Bug      Niesthrea louisianica