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.
https://www.facebook.com/media/set/?set=a.5852056758144174&type=3
https://www.facebook.com/media/set/?set=a.5852056758144174&type=3
Number of Ramblers today: 31
Reading: Dale brought an excerpt from "Crow Planet: Essential Wisdom from the Urban Wilderness" by Lyanda Lynn Haupt. (Read by Terry).
Announcements:
What: 2022 Pollinator Fair
When: Saturday, May 21st, from 10:00 a.m. until 4:00 p.m.
Where: Madison County Library,
Directions: From Athens, take
Hwy. 29 north to Danielsville. At the red light north of the old
courthouse roundabout, take Hwy 98 west for 1.3 miles. The library will
be on your left.
Details: The event is hosted by the Ladies Homestead Gathering of Madison County. Don will be presenting on his documentation of the common roadside pollinators in south Madison County. In addition, there will be presentations by other speakers. Carole Knight, Madison County Extension Coordinator and Ag Agent will talk about the importance of pollinators in Georgia and author Cathy Payne will talk about how to turn your yard into a pollinator sanctuary, in particular, addressing removing invasive plants and replacing them with beneficial native flora.
Today's Route: From the Children's Garden pergola we went through the American South Section, crossing the Flower Bridge, then through the China and Asia Section, the Native American and Southeastern Tribes Section and over to the Mediterranean and Middle East Section. Then we went across the lawn to the Pitcher Plant Bog. We retraced our path to the Freedom Plaza before we returned to the parking lot.
OBSERVATIONS:
Piedmont Azalea
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| Piedmont Azalea |
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| Single flower of Piedmont Azalea The stamens and style project far forward, The style is longer than the stamens and ends with the stigma. The stamens are tipped with the brown anthers that contain pollen. |
Azaleas are justly celebrated for their masses of colorful flowers. Humans are not the only species attracted to the blossoms; casual observers have noticed a variety of small bees visiting the flowers and assumed that they were responsible for pollination. But assumption is not proof, only opinion. Looking at the structure of the flower one thing stands out: the stamens and pistil style project a considerable distance in front of the petals. The nectar is at the base of the flower’s throat, so an insect, like a bee, who was seeking nectar would not come in contact with either the pollen producing anthers or the stigma of the pistil which is at the end of the style. (In order to produce seeds pollen needs to be deposited on the stigma.) Small bees that are collecting pollen to feed to their offspring climbed up the stamen to the anther. In doing this the stamen was bent away from the stigma of the flower. This suggested that such bees would not be effective pollinators.Working at Mountain Lake Biological Station in Virginia, a team of researchers devised a way to test these ideas on a related species of Azalea. More details of the study can be found here. The surprise of their study was that the most effective pollinator was the Eastern Tiger Swallowtail butterfly and it carried the pollen on its wings, not its body! Swallowtail butterflies flap their wings while nectaring on flowers. The azalea anthers and stigma are arranged at the correct distance to contact the butterflies wings as they sip nectar. Not only do the wings pick up pollen, they also deposit pollen on the stigma. The surprise here is that the pollen is carried on the wings of the butterfly, not the body.
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Franklinia alatamaha
Extinct in the wild, this unique species is conserved in arboreta and botanical gardens around the world. In 1765, John Bartram and his son, William, journeyed to the Altamaha River in Georgia, where they first spotted the tree on the banks of the Altamaha River. Several years later, William returned to the location to collect seed to collect seed. Later, in 1791, he wrote, "We never saw it any other place, nor have I ever seen it growing wild, in all my travels, from Pennsylvania to Point Coupe, on the banks of the Mississippi." He brought the seeds back to Philadelphia. His collection of the species was timely; within 50 years, the tree was extinct in the wild. All living Franklin trees-which Bartram named for family friend Benjamin Franklin-are descended from the seeds Bartram collected.
(Factual information from the Arnold Arboretum website)
You may have noticed that the specific epithet is not the way we spell "altamaha." This not a typo; the original description spelled it that way. The rules of nomenclature state that the original spelling, even if incorrect, must stand.)
Palmately Compound leaves
A compound leaf is a leaf with two or more leaflets. So how do you tell when a "leaf" is a leaf or a leaflet? Look at where it is attached. Is there a bud there or is the bud absent? If present, you're looking at a leaf, otherwise ii is a leaflet.
If you are looking at a leaflet you are looking at a leaf that is made up of many leaflets -- it's a compound leaf. There are two types of compound leaves: palmate and pinnate. A palmately compound leaf has all of its leaflets attached at the same point. The trees and shrubs of the Buckeye genus, Aesculus, have palmately compound leaves.
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| Bottlebrush Buckeye has palmately compound leaves. Each leaf is composed of five leaflets that arise from the end of the leaf stalk (the petiole). |
If you are looking at a leaflet you are looking at a leaf that is made up of many leaflets -- it's a compound leaf. There are two types of compound leaves: palmate and pinnate. A palmately compound leaf has all of its leaflets attached at the same point. The trees and shrubs of the Buckeye genus, Aesculus, have palmately compound leaves.
Arum family (Araceae)
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| Aroid plants have seen better days. |
In the China section of the Garden we found a group of unusual plants that look like they belong to the Arum family. (That's the family of the Jack-in-the-Pulpit. )
The spathe was dark and mottled with maroon blotches, giving the impression of decaying flesh. On the previous day Emily and I saw clouds of fungus gnats and a green bottle fly swarming about these plants.
A fungus gnat is a fly about the size of a mosquito. It's larvae feed on mushrooms or decaying organic matter, as does the green bottle fly larvae. Many aroids are known to produce the scents of decaying animal flesh or vegetation to attract pollinators.
Pitcher Plant Bog:
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| Purple and White-topped Pitcher Plants |
We saw several species of pitcher plants in the little artificial bog, including Yellow Pitcher Plant, Purple Pitcher Plant and White-topped Pitcher Plant.
Pitcher plants can grow in very nutrient poor soils because they trap and digest insects (and sometimes small vertebrates). The pitcher part of the plant is a modified leaf. Imagine a long leaf that is curled about its long axis so that the lateral edges meet and fuse. This makes a cylinder. If the lower opening is sealed and the other end carved out to form a flap then you've made a pitcher. Fill it with water and you're ready to trap bugs. The inner surface of the lip is slick and waxy and the upper portion of the pitcher has downward pointing bristles. These features prevent insects that fall into the pitcher from crawling out. Eventually they die from exhaustion and are gradually digested in the pitcher "soup." Each pitcher develops its own ecosystem microbes that feed on drowned insects and mosquitoes that feed on the microbes. Elements like Nitrogen and Phosphorus are freed into the soup and absorbed by the pitcher walls.
Pitcher plant flower structure
The flowers of pitcher plants are also bizarre. I'll review flower structures so you can appreciate just how different they are. In a typical plant the central structure of the flower is the pistil. It is made of three parts: ovary, style and stigma. The ovary is where the seed will develop. The style is a tube the connects the ovary to the stigma. The stigma is the surface that receives the pollen. Pollen lands on the stigma, the pollen grain germinates and a pollen tube begins to grow through the style. Eventually the pollen tube, which carries the sperm nucleus, reaches the ovule in the ovary. That's the female part of a flower.
Surrounding the pistil are the stamens, the male reproductive structures of the flower. Stamens have two parts, the filament and the anther. The filament holds the anther aloft and the anthers make and hold the pollen grains until they are needed.
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| Petals pushed aside to show the five pointed style of a pitcher plant. |
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| The fuve-pointed style is pushed aside to show the mass of stamens and anthers. Pollen released from the anthers will fall into the style "basket" below the anthers. |
Pitcher plant flowers are held upside down. There are five pistils fused together to form a five chambered ovary. The fused styles have stretched out to form an umbrella shape and that "umbrella" reaches beyond the stamens that surround the fused ovaries. Turn the flower upside down and you can see how pollen can fall out of the anthers into the stylar umbrella. Where are the stigmas? There were five fused pistils, making the five ribs of the umbrella. The stigmas are at the end of each rib.
When a bee forces its way into a pitcher plant flower it walks across a floor of pollen grains that are picked up by its hairy body. When it enters or leaves it crawls over the stigmatic surfaces at the ends of the "ribs."
Plant galls are abnormal growths on plant parts. They may be caused by bacteria, viruses, fungi, and a variety of insects. Today, we saw two types of galls induced by insects.
Witch Hazel Cone Gall Aphid
The puzzle: The Garden has at least four kinds of Witch Hazel: Common Witch Hazel (native to Georgia), Ozark Witch Hazel (native to Missouri), Japanese Witch Hazel and Chinese Witch Hazel. The first four of these can be found growing near each other in the Shade Garden and we have never seen the Cone Gall on the Japanese plants and only a few galls on the Ozark plants. It looks like the aphids are species-specific, either because they only recognize the native species or they actively discriminate against the non-native plants. But the mystery is that we found numerous galls on the Chinese Witch Hazel. Something strange is going on here.
The complex life history of the Cone Gall Aphid begins in autumn with the aphid eggs laid near the leaf buds of the Witch Hazel. As the leaves emerge from their buds the eggs hatch and the aphids, all females, lay an egg on the young leaves. This causes the leaf to grow a hollow conical structure that surrounds the freshly hatched aphid. Inside this protective gall the aphid matures and begins to produce daughters asexually. The aphids feed by sucking fluids from the walls of the gall. Soon there 50 or more aphids in each gall and they develop wings. The winged aphids emerge from the gall and fly to an alternate host plant, a Birch tree. (In our area this would be a River Birch.) There they produce asexual wingless offspring the feed on the lower surface of the Birch leaves. Several more generations of wingless aphids are produced until autumn when sexual, winged adult aphids are produced. These mate and the females disperse, seeking their Witch Hazel host and laying eggs near the leaf buds, completing the life cycle.
Another mystery: Among the green cone-shaped galls we usually find a few red galls. I've unsuccessfully tried to find more information about the gall color. Your guess is as good as mine. I suspect it is a polymorphism: some aphids produce a substance that stimulates anthocyanin production by the Witch Hazel. Other aphids don't produce this substance. Some people have brown hair, some red. It's natural variation (code words to cover ignorance).
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| Witch Hazel Cone galls on Chinese Witch Hazel leaf. |
Witch Hazel Cone Gall Aphid
The puzzle: The Garden has at least four kinds of Witch Hazel: Common Witch Hazel (native to Georgia), Ozark Witch Hazel (native to Missouri), Japanese Witch Hazel and Chinese Witch Hazel. The first four of these can be found growing near each other in the Shade Garden and we have never seen the Cone Gall on the Japanese plants and only a few galls on the Ozark plants. It looks like the aphids are species-specific, either because they only recognize the native species or they actively discriminate against the non-native plants. But the mystery is that we found numerous galls on the Chinese Witch Hazel. Something strange is going on here.
The complex life history of the Cone Gall Aphid begins in autumn with the aphid eggs laid near the leaf buds of the Witch Hazel. As the leaves emerge from their buds the eggs hatch and the aphids, all females, lay an egg on the young leaves. This causes the leaf to grow a hollow conical structure that surrounds the freshly hatched aphid. Inside this protective gall the aphid matures and begins to produce daughters asexually. The aphids feed by sucking fluids from the walls of the gall. Soon there 50 or more aphids in each gall and they develop wings. The winged aphids emerge from the gall and fly to an alternate host plant, a Birch tree. (In our area this would be a River Birch.) There they produce asexual wingless offspring the feed on the lower surface of the Birch leaves. Several more generations of wingless aphids are produced until autumn when sexual, winged adult aphids are produced. These mate and the females disperse, seeking their Witch Hazel host and laying eggs near the leaf buds, completing the life cycle.
Another mystery: Among the green cone-shaped galls we usually find a few red galls. I've unsuccessfully tried to find more information about the gall color. Your guess is as good as mine. I suspect it is a polymorphism: some aphids produce a substance that stimulates anthocyanin production by the Witch Hazel. Other aphids don't produce this substance. Some people have brown hair, some red. It's natural variation (code words to cover ignorance).
Maple Eye Spot gall
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| Maple Eye Spot gall (upper surface of Red Maple leaf) |
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| Maple Eye Spot gall (under surface of leaf showing exit holes) |
This pretty gall was induced by a flying insect called a "midge." Midges resemble mosquitos but do not bite. I'm indebted to fellow rambler Bill Sheehan for the identification:
"According to this source, midge larvae emerge from the galls on the bottom of the red maple leaf in 8 to 10 days, drop to the soil and pupate. There is only one generation a year. Since all of the galls we saw had exit holes, the larvae are apparently all in the soil now pupating and waiting until next year to emerge and start the cycle again. Given the moist appearance of the galls, this probably happened pretty recently."
https://content.ces.ncsu.edu/maple-eyespot-gall-midge-acericecis-ocellaris-osten-sacken-diptera-cecidomyiidae
Tree Growth Patterns
Each year a tree adds to its size as new shoots emerge from their buds. For many trees these terminal buds contain the entire years worth of growth. For these trees their shoots elongate and leaves expand but no additional leaves are produced. The entire summer's growth occurs within the first few weeks. Since the number of leaves is set in the bud that formed in the previous year this pattern of growth is called determinate or preformed.
But not all trees compress their annual growth within this short period of time. Their buds contain only a single leaf that emerges with bud-break. Growth of the shoot does not cease. Instead, new leaves appear for the rest of the growing season. Such a growth pattern is called indeterminate or sustained.
How can you tell which pattern a tree follows? If the new growth has a terminal bud it is preformed growth; no terminal bud, sustained growth.
But, as always, biological definitions have fuzzy edges. Some common plants have a mixture of preformed and sustained growth. The begin with a short preformed shoot that continues to add leaves throughout the growing season.
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| White Oak new shoot with terminal bud. (photo by Emily Carr) |
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| Pawpaw new shoot showing indeterminate growth. Note absence of terminal bud presence of new developing leaves. (photo by Dale Hoyt) |
American beech, Ash, Black cherry, Hickories, Oaks
Trees with indeterminate (sustained) growthBirch sp., Cottonwood, Elm, ,Flowering dogwood, Hackberry, Holly, Pawpaw, Redbud. Sycamore, Tulip poplar
Trees with both growth formsRed maple, Sugar maple, Sweetgum
[source]
OBSERVED SPECIES:
Oak-leaf Hydrangea Hydrangea quercifolia
Harvestman Class Arachnida: Order Opiliones
Beardtongue Penstemon sp.
Fringed Bluestar Amsonia cilliata
Native azalea Rhodendron sp.
Franklin Tree Franklinia alatamaha
Bottlebrush Buckeye Aesculus parviflora
Tea Trees Camellia sinensis
Orchard Orbweaver Leucauge venusta
Chinese Witch Hazel Hamamelis mollis
Arum ?? Family Araceae
Paperbark Maple Acer griseum
Whitebark Magnolia Magnolia hypoleuca
Fragrant Snowbells Styrax obassia
Indian Pink Spigelia marilandica
Rose Hooktip Moth Oreta rosea
Yellow Pitcher Plant Sarracenia flava
Purple Pitcher Plant Sarracenia purpureum
White-topped Pitcher Plant Sarracenia leucophylla
Inch worm/Geometer moth caterpillar Order Lepidoptera: Geometridae
Red Maple Acer rubrum
Ocellate Gall Midge Acericecis ocellaris
Harvestman Class Arachnida: Order Opiliones
Beardtongue Penstemon sp.
Fringed Bluestar Amsonia cilliata
Native azalea Rhodendron sp.
Franklin Tree Franklinia alatamaha
Bottlebrush Buckeye Aesculus parviflora
Tea Trees Camellia sinensis
Orchard Orbweaver Leucauge venusta
Chinese Witch Hazel Hamamelis mollis
Arum ?? Family Araceae
Paperbark Maple Acer griseum
Whitebark Magnolia Magnolia hypoleuca
Fragrant Snowbells Styrax obassia
Indian Pink Spigelia marilandica
Rose Hooktip Moth Oreta rosea
Yellow Pitcher Plant Sarracenia flava
Purple Pitcher Plant Sarracenia purpureum
White-topped Pitcher Plant Sarracenia leucophylla
Inch worm/Geometer moth caterpillar Order Lepidoptera: Geometridae
Red Maple Acer rubrum
Ocellate Gall Midge Acericecis ocellaris
