Leader for today's Ramble: Linda
Authors of today’s Ramble report: Linda and Don. Comments, edits, and suggestions for the report can be sent to Linda at Lchafin@uga.edu.
Insect identifications: Don Hunter, Heather Larkin, Bill Sheehan
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. Photos may be enlarged by clicking them with a mouse or tapping on your screen.
Number of Ramblers today: 22
Today's emphasis: Seeking what we found in the Dunson Native Flora Garden and nearby powerline right-of-way
Show and Tell: Bill brought some amazing galls that he collected from Virginia Creeper vines on his property in western Clarke County. These galls are created by a gall midge, Lasioptera psedrae, that exclusively uses Virginia Creeper as a host plant. They are abundant near Bill's house, yet are otherwise unknown on iNaturalist, with very little info elsewhere on the internet. |
| Virginia Creeper galls Photos by Bill Sheehan |
Reading: Linda read a compilation of quotes (with minor edits) by Robin Wall Kimmerer, author of Gathering Moss and Braiding Sweetgrass, on the topic of naming plants.
“It’s a sign of respect to learn the name of someone else, a sign of disrespect to ignore it and yet the average American can name over a hundred corporate logos and only ten plants. Is it a surprise that we’ve accepted a political system that grants personhood to corporations and no status at all to wild rice and redwoods? Learning the names of plants and animals is a powerful act of support for them. Words and names are the ways we humans build relationships, not only with each other, but also with plants… But one of the difficulties … is that when we name something with a scientific name, this name can become an end to inquiry. We say, “well, we know it now. We’re able to systematize it and put a Latin binomial on it, so it’s ours. We know what we need to know.” But that is only looking at the morphology of the organism, at the way that it looks. It ignores all of its gifts, its relationships. It’s a mechanical, wooden representation of what a plant really is… But when we learn their names and their gifts and their relationships – it opens the door to reciprocity and to an intimacy that speaks of careful observation. Intimate connection allows recognition in an all-too-often anonymous world. Intimacy gives us a different way of seeing. Having the words for plants and their relationships at your disposal, you can see more clearly. Finding the words is another step in learning to see.”
Announcements/Interesting Things to Note:
Reminder: The Great Southeastern Pollinator Census is coming up next week on August 18 and 19. This website will give you all you need to know to participate.
Today's
Route:
We walked through the Shade Garden down to the Dunson Garden, exited near the Purple
Passionflower fence along the road, and briefly headed out into the open ROW until
the rain sent us back to our vehicles.
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| Don and Heather were entertained by a Spiny Oakworm Moth caterpillar on some of the dying vegetation in the beds across from the arbor |
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| Recently cut stump of a Pignut Hickory in the Dunson Garden The growth rings indicate that the tree was 35-40 years old when cut. |
The
impact of our recent storms on forests is readily seen in Dunson,
where the ground is littered with twigs and leaves, and the paths have been scoured
by fast flowing water, washing the mulch cover away and leaving exposed soil. Several trees were blown over. Joey, the Dunson Curator,
and his staff and volunteers have a lot of work ahead of them.
Trees in the Earth's temperate zones expand in girth each year during the spring and summer and rest in the winter, a pattern that results in annual growth rings. Each spring, new growth is produced from a layer of rapidly dividing cells under the bark that completely encircles the trunk from top to bottom like a tight sleeve. This layer, called the vascular cambium, produces xylem cells inwards by division. Xylem cells are the tree’s plumbing, carrying water from the soil through the entire body of the tree, including the leaves. Water (and dissolved nutrients) are drawn upward, cell to cell, through pores in the cell walls. The first cells produced in the spring are called “spring wood;” they are large, thin-walled, and light in color. Later in the growing season, the cambium produces xylem cells that are smaller, thick-walled, and darker in color. This growth is called “summer wood.” Together, these two types of cells form one annual growth ring.
Two other types of “wood” are visible on the cut surface of this hickory trunk: sapwood and heartwood. The youngest wood, consisting of both spring and summer wood, lying just inside the bark and light in color, is called sapwood: it is living and carries water and nutrients throughout the tree. Older cells, toward the center of the trunk, are dead and no longer transport water. Instead, they are packed with resin, tannin, and other compounds that protect against rot and strengthen the trunk; these compounds also darken the cells so that heartwood, regardless of whether it started out as “spring wood” or “summer wood,” is darker in color than sapwood. Trees can live long lives without heartwood–we’ve all seen old, hollow trees that are still healthy and actively growing.
So
far, we’ve only talked about xylem, the type of cells produced inward by the vascular
cambium. At the same type, the cambium is producing another ring of cells outward–these
are phloem cells, the tissue that translocates carbohydrates from the leaves to
the non-photosynthetic parts of the tree. Girdling works to kill trees by
interrupting the flow of carbohydrates to the roots. Phloem cells
typically live only one year and eventually crumble and become part of the inner bark. (Outer
bark is produced by another type of cambium layer called the cork cambium, but
we’ll leave that for another ramble.) NB: this discussion of xylem, phloem, cambium,
etc. is generalized; there is much variation on these themes depending on the species
and the environment in which a given tree is growing.
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| Common Elephant’s Foot blooming in the deep shade of the Dunson Garden. |
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| Hammock Spider-lily is one of the few plants that flowers in the summer shade of the Dunson Garden |
Most of the Spider-lilies we saw were beat up by recent storms or browsed to the ground by deer. Don found one gorgeous intact plant in full flower. There are 16 native species of Hymenocallis in the southeast; this is the only one to occur in upland forests and the only one in the Georgia Piedmont. One of the few herbaceous plants to bloom in the deep shade of the midsummer forest, this species is truly spectacular in bloom. Its flower has six narrow, flaring tepals (3 petals + 3 nearly identical sepals) with a spread up to 8 inches and a central, cup-like membrane called a corona (the genus name, Hymenocallis, means "beautiful membrane"). The six stamens, tipped with golden anthers, are fused to the corona. The flowers open in the late afternoon and are visited during the night by moths attracted by the sweet fragrance. Each flower remains open less than 24 hours. (Wondering what hammocks have to do with this plant? A hammock is a term used mostly in the Coastal Plain to describe a patch of hardwood forest surrounded by grasslands or longleaf pine woodlands. If it were up to me, I’d call this species Woodland Spider-lily.)
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| Both female and male Spicebush plants were planted in Dunson, and every year we find a few fruits on the female shrub. Are we late comers after the birds have taken most the fruits, or does this particular shrub only produce a few? |
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| Spicebush
Swallowtail adult (left) and caterpillar (right) photos by Sandy Shaull |
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Tulip Tree Beauty moth lays its eggs on the leaves of Spicebush, Tulip Tree, and several other trees. Don took this photo of a Tulip Tree Beauty Moth on July 13 in the Dunson Garden. |
We left the Dunson Garden to seek out the Purple Passionflower vines that hug the fence
between the entrance road and the lower section of Dunson, searching for signs
of Gulf Fritillaries. It’s still a little early for a full crop of these
butterflies, though we did see one caterpillar on the Passionflower vine and one adult on a nearby shrub.
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| Gulf Fritillary adult |
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| Gulf Fritillary caterpillar |
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| Passionflower vines bear small, button-like
structures at the base of most leaf blades. These are extrafloral nectaries –
nectar-producing glands that have no connection to flowers or pollinators.
Instead, the sugary substance exuded by these glands attracts ants, such as the one that Don captured in this photo, that sip the nectar and defend the plant from caterpillars. |
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| Spotted Bee-balm (or Horsemint) is blooming along the fence. Its pink bracts catch the attention of pollinators, the maroon spots on the yellow flowers direct them to the nectar produced deep inside the flower, and the wide gap between the flower’s two lips ensures that larger bees, such as carpenter bees and bumblebees, can fit right in. |
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| Earlier this year the right-of-way that crosses the lower floodplain was mowed and ramblers were dismayed. However, vegetation is lush here after a summer of rain and high temperatures. Linda worried out loud that mowing may favor the wingstems (Common Wingstem and Yellow Crownbeard) that spread aggressively in the ROW, reducing the diversity of other plant species. Those species have a dense underground network of rhizomes that help it spring back quickly after disturbance and that exclude less robust species. |
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| Heather captured a Mottled Tortoise Beetle on one of the Morning Glory vines growing along the edge of the mown path in the ROW. She’d spotted several leaves with many tiny, round holes and knew that to be an indicator of tortoise beetle foraging. |
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| High-bush Blueberries are ripening near the lower entrance to Dunson. |
At this point, rain began to come down in earnest and we turned back into the woods, where Don spotted masses of Spittlebug foam on several branches
Although the literature tells us that American Beech trees host many moth caterpillars, it’s unusual to find much evidence of this on Beech leaves at the Garden. So, when Don noticed several American Beech leaves that had been almost completely skeletonized, he stopped to see if the culprit could be found. He soon found many Spotted Datana Moth caterpillars gathered together on a twig amongst several skeletonized leaves.
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| Skeletonized Beech leaves and masses of
Datana caterpillars. Photos of adult moths can be seen here. |
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| Close-up of Datana caterpillars Photo by Heather Larkin |
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| Imperial Moth
caterpillar (probably) photo by Heather Larkin |
SUMMARY OF OBSERVED SPECIES
Virginia Creeper gall Lasioptera psedrae
Virginia Creeper Parthenocissus quinquefolia
Spiny Oakworm Moth caterpillar Anisota stigma
Gulf Fritillary (adult and caterpillar) Agraulis vanillae
Pignut Hickory Carya glabra
Common Elephant’s Foot Elephantopus tomentosus
Hammock (or Woodland) Spider-lily Hymenocallis occidentalis
Virginia Creeper Parthenocissus quinquefolia
Spicebush Lindera benzoin
Japanese Beautyberry Callicarpa japonica
Smooth Chanterelles Cantherellus lateritus
Mulberry Weed Fatoua villosa
Purple Passionflower Passiflora incarnata
Ashmead’s Acrobat Ant (tentative) Crematogaster ashmeadi
Spotted Bee-balm Monarda punctata
American Wisteria Wisteria frutescens
Common Wingstem Verbesina alternifolia
Yellow Crownbeard Verbesina occidentalis
Mottled Tortoise Beetle Deloyala guttata
Beaked Panicgrass Panicum anceps
Highbush Blueberry Vaccinium corymbosum
Red Morning Glory Ipomoea coccinea
American Beech Fagus grandifolia
Spotted Datana Moth Datana perspicua
Muscadine Grape Muscadinia rotundifolia
Spittlebug, Superfamily Cercopoidea
Imperial Moth caterpillar Eacles imperialis
