Leader
for today’s Ramble: Emily
Authors
of today’s Ramble report: Linda, Dale, and Don. Comments, edits, and
suggestions for the report can be sent to Linda at Lchafin@uga.edu.
Insect
identifications: Don
Hunter, Heather Larkin, Dale Hoyt
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.
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| Carolina Anole shedding its skin on a Giant Onion inflorescence |
Number
of Ramblers today: 34
Today’s
emphasis: Flowering and fruiting in the Dunson Native Flora Garden.
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| Ramblers exploring the Dunson Native Flora Garden |
Reading: Emily read from “Sandhills,”
a chapter in Janisse Ray’s Drifting into Darien (2011). Here is the
first paragraph of a longer section that Emily read; see the end of this report for the full
reading…
“I’m going to give you some
advice right away about botanists. Never go out in the woods with them. Never
go anywhere. If you do, you’ll never get to where you’re going. They
want to stop every few feet to bend down and look at something. They carry little
magnifying glasses with them so they can count parts of flowers so small they’d
get lost in a thimble. The botanists are shamelessly looking to see if leaves
are hairy or smooth, if they have glands, how their veins run. You have to keep
your body covered when you’re with botanists…”
Show and Tell:
Terry
brought a Stanfield Air Systems flyer which mentions the Nature Ramblers as a “must-do”
activity in Athens.
Linda
brought a Post Oak twig from Bald Rock, a granite outcrop at the International
Horse Park in Rockdale County. Post Oak leaves are all about limiting water loss,
a challenge facing any plant on a granite outcrop. They have a thick, waxy cuticle on
the upper leaf surface that retains water and reflects light, and the lower
surface is densely and finely hairy. The leaves on this tree are
narrower than Post Oak leaves in woodlands, reducing the amount of surface from
which moisture can be lost.
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| Post Oak is in the white oak subgenus – these tiny acorns will mature this summer and drop in the fall; red oak acorns take two years to mature. |
Announcements/Interesting Things to Note:
Emily urged everyone to join the Friends of the Garden if
they haven’t already.
Here’s an interesting article in the May 18 edition of the Washington Post: “Why birds and
their songs are good for our mental health.”
Today’s Route: We left the arbor next to the Children’s
Garden and walked through the Shade Garden to the Dunson Native Flora Garden.
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| The canopy is closing in the Dunson Garden. |
OBSERVATIONS:
As we
made our way through the Shade Garden, we came across a Witch Hazel with a heavy
crop of Witch Hazel Galls, each containing 50-70 aphid larvae.
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| Witch Hazel galls start out green, then turn red. In nature, red is often a warning color – “danger, keep away!” I wonder if this change in gall color discourages birds that would otherwise try to open the gall and eat the larval contents. |
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| The aphids that matured inside the galls have left their shelters, exiting via these holes on the lower leaf surface, and gone in search of the River Birches that will support the next several generations of their species’ life cycle. |
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| The Dunson Garden welcomed us with an amazing show of Black Cohosh flowers this year. It’s been a wet, cool spring in Athens, just the right combination of conditions for this largely Appalachian species. “Forest Candles” would make another good common name. Photo by Aubrey Cox |
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| Black Cohosh flowers have four tiny petals and rely on dozens of showy, bright white stamens to attract pollinators – a variety of flies, bees, and beetles in search of pollen; the flowers do not produce nectar. Black Cohosh is the only host for the caterpillars of the small blue Appalachian Azure butterfly which lays its eggs on the flowers. |
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| Tall Thimbleweed, a member of the Buttercup Family, at the entrance to the Dunson Garden |
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| Leaf Miner trails on the leaves of Columbine (left) and Golden Ragwort (right). Good luck finding the origin of the Columbine’s trail! |
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| Perfoliate Bellwort fruit Like most of our spring ephemeral species, the seeds of Perfoliate Bellwort are dispersed by ants drawn to the seeds by the their fatty elaiosome “handles.” |
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| Snail grazing trails on the trailside bench Don explained to the group that the snail extends its radula, a kind of rasping tongue, and sweeps its head back and forth while scraping algae into its mouth. |
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| Dwarf Pawpaw fruit It’s pretty unusual to spot a fruit; they’re typically snagged by squirrels and raccoons before humans find them. |
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| A late-flowering Indian Pink |
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| Daddy Longlegs on Early Meadowrue leaves |
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| A colorful palette of lichens and mosses on the trunk of a Cucumber Magnolia tree |
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| Dale explained the basics of molecular genetics in response to a question by Randall, a new rambler. photo by Gary Crider |
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| Broad Beech Ferns lifting their foxy heads |
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| New York Ferns “burning their candles at both ends” |
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| Lace Bug photo by Heather Larkin |
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| Several of the signs in the Dunson Garden show these strange patterns around the edges. What’s going on? Squirrels and chipmunks are rodents and their incisors are constantly growing. To keep them in check and also in sharp working order, squirrels and chipmunks will chew on almost anything: tree trunks, metal signs and gutters, rocks, outdoor furniture…. |
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| Goldenseal with their raspberry-like fruits |
Goldenseal
is a highly sought after medicinal herb; like Ginseng, it has been used for
centuries to treat a variety of ailments including fever, bacterial
infections, colds, gastric upset, skin rash, gum disease, and allergies. Wild
populations of Goldenseal have been nearly wiped out by overzealous harvesting,
but the plants are now grown commercially in the Southern Appalachians and
elsewhere, hopefully relieving some of the pressure on natural populations. The National Center for Complementary and Integrative Health reports that there is
little scientific evidence for Goldenseal’s medicinal benefits.
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| Fuzzy fruits of Wood Poppy |
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| Oak-leaf Hydrangea inflorescence The large showy flowers are sterile but serve to lure pollinators to the hundreds of tiny, fertile flowers tucked in closer to the stem. |
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| Spicebush fruits will turn a bright, clear red when ripe. |
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| Painted Buckeye fruits |
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| Fly Poison in flower Earlier opening flowers at the base of the inflorescence have turned green. |
Fly Poison’s
white flowers turn green when the stigma – the part of the pistil that accepts
pollen – is no longer receptive. After changing color, the flowers become more
or less invisible to visually oriented pollinators, a strategy that prevents insect-borne pollen from being wasted on unreceptive flowers.
Fly Poison is among the most poisonous plants in North America. Toxic alkaloids are found in all parts of the plant,
and are especially concentrated in the bulb. Native Americans and European colonists
mashed up the bulb with honey, molasses, or sugar to attract and poison flies.
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| A Milkweed Bug visiting a Purple Milkweed inflorescenceThe small patch of Purple Milkweed
on the western edge of the Dunson Garden is flowering. Although common in several |
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| Another rare plant species, Smooth Purple Coneflower, thrives in the sunny western end of the Dunson Garden. It is federally listed as Endangered. Photo by Linda Chafin |
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| Yucca plants in glorious flower photo by Linda Chafin |
Finding
the Yucca patch in bloom is one of the high points of late spring at the Botanical
Garden. This year, the plants seem especially laden with flowers. We stopped as
always to hear Dale explain what must be one of the most fascinating and complex examples
of plant-insect mutualism.
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| photo by Linda Chafin |
Here is what Dale wrote about Yucca Moths in the May 18, 2017
Nature Ramble report.
“At the lower end of the
Dunson Garden is a group of Yucca plants just starting to bloom. Hiding inside
the open blossoms are small, gray Yucca Moths, about 1/2 inch in length.
Shaking the stem of the inflorescence disturbs the moths and they fly out.
These moths are in the flowers to lay eggs in the ovaries, where the Yucca
seeds develop. When the eggs hatch the caterpillars begin to feed on the
developing Yucca seeds. Of course to get seeds the flower must be pollinated
and here things get a little surreal. The principal pollinator of the yucca
flower is – the Yucca Moth!
The Yucca stigma (the part of
the pistil that receives pollen) is unusual. Instead of being exposed to the
air it is tucked away in a recess at the end of the pistil. To be pollinated
pollen must be inserted into the recess. This is the job of the Yucca Moth.
When night falls the female moth gathers pollen from the anthers of her flower
and rolls it into a ball. She then flies to another flower and, using a unique,
tentacle-like mouth part found only in Yucca Moths, she tamps the pollen ball
into the stigma recess. When she finishes, she walks to the bottom of the pistil
and inserts a number of eggs into the wall of the ovary. In a peculiar sense she is
farming Yucca seeds. If she has done her job, there will be more than enough
developing seeds to feed all her caterpillars, with some left over to
perpetuate the Yucca.
But what if she lays too many
eggs? Or another moth chooses to lay eggs in the same blossom? This is where
the plant gets to “decide” what happens. It can somehow sense when
the load of caterpillars is too great for its seeds to survive. Then the plant
aborts the blossom. Researchers have examined aborted flowers and found
multiple oviposition scars on their ovaries, showing that the moths often lay
more eggs that a single blossom can support.
There is one more wrinkle in
this system of checks and balances – cheating moths. There are several species
of Yucca Moths that lack the special tentacle of the mutualist Yucca Moth.
These moths can’t and don’t pollinate Yucca flowers, they just lay their eggs
in them, taking advantage of the efforts of other, pollinating, moth species.
They are free-loaders, parasites on a mutualistic relationship.
When the caterpillars mature
they eat their way out of the ovary and crawl into the leaf litter on the
ground below the plant and construct a cocoon. Moths from some of these will
emerge the following spring, but others cocoons can remain dormant for several
years. One entomologist had a cocoon in a jar on his desk for over 10 years
before a moth emerged.
This is a matter of critical
timing. The moths have a short life span and they must emerge while the Yuccas
are flowering. If they emerge too early they may die before the Yucca blooms;
too late, and they will not find any flowers to pollinate and oviposit in. How
the plant and the insect are synchronized is currently unknown.”
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| Yucca Moth on a Yucca flower’s densely hairy stamen Photo by Heather Larkin |
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| Eastern Leaf-footed Bug |
Don noted on his Facebook page: “We always look for, and find, Eastern Leaf-footed Bugs on the Yucca plants. Later in the season, after the flowers are gone and the stalks are beginning to dry out, hordes of these bugs can be seen on these plants.” The relationship between these bugs and Yuccas has been noted by another biologist blogger elsewhere in the south: “The bugs feed on the plants’ tissues by piercing the flesh of the stem or bud with their beak-like mouthparts and then sucking and ingesting the plants’ juices. Since the flower stalk will die after flowering anyway, this feeding method typically isn’t too detrimental to the health of the plant.”
SUMMARY OF OBSERVED AND DISCUSSED SPECIES
Post Oak Quercus stellata
Dogwood gall Resseliella clavula
American Witch-hazel Hamamelis virginiana
Witch Hazel leaf gall aphid Hormaphis cornu
Tall Thimbleweed Anemone virginiana
Black Cohosh Actaea racemosa
Ashe’s Magnolia Magnolia ashei
Columbine Aquilegia canadensis
Golden Ragwort Packera aurea
Daddy Longlegs Family Opiliones
Early Meadowrue Thalictrum dioicum
Perfoliate Bellwort Uvularia perfoliata
Dwarf Pawpaw Asimina parviflora
Cucumber Magnolia Magnolia acuminata
Indian Pink Spigelia marilandica
New York Fern Thelypteris noveboracensis
Broad Beech Fern Phegopteris hexagonoptera
Lace Bug Family Tingidae
Goldenseal Hydrastis canadensis
Lauxaniid Fly Neogriphoneura sordida
Wood Poppy Stylophorum diphyllum
Oak-leaf Hydrangea Hydrangea quercifolia
Spicebush Lindera benzoin
Fly Poison Amianthium muscitoxicum
Spotted Wintergreen Chimaphila maculata
Long-leaved Bluet Houstonia longifolia
Yucca, Spanish Bayonet, Adam’s Needle Yucca filamentosa
Yucca Moth Tegeticula yuccasella
Eastern Leaf-footed Bug Leptoglossus phyllopus
Purple Milkweed Asclepias purpurascens
Smooth Purple Coneflower Echinacea laevigata
Large Milkweed Bug Oncopeltus fasciatus
Painted Buckeye Aesculus sylvatica
Reading (continued from above): From “Sandhills,”
a chapter in Janisse Ray’s Drifting into Darien (2011), pp. 162-167.
‘I’m with a group of people who have their pants tucked in
their socks and who are crawling around in the grass with magnifying glasses.
They are examining the grasses, in fact, and speaking a language I don’t
understand.
“I think these are Aristida
purpurascens.”
“Oh, here’s a Little Bluestem,
related to Andropogon.”
Come on, people, you’re embarrassing me. Somebody’s gonna
pass on the road and see me out here with you all crawling around in the dirt.
I live in this county, remember? Also, I want to see what’s at the top of this
little mountain, so we’ve got to pep it up a little.
“We’ve got Vitis rotundifolia
all over the place.”
“Here’s Smilax pumila.”
What? Have we been invaded? This sounds like Star Wars talk
to me.
A few feet ahead is a flower in bloom. Do not give these people
a flower. They go crazy.
“Liatris,” one says.
“Graminifolia, I think,”
says another.
“Oh dear, that species has been broken into several. The problem
is categorizing…”
The problem is that getting up this fifty-foot hill
is going to take all day at this rate. Step back, people. You’re smothering
that poor flower, peering down its throat, trying to see its ovaries… Someone
screams. I run over, thinking they’ve found a mummy, or gold.
“Sorghastrum
secundum!” the guy says. “What?” I say. “Sorghastrum secundum!”
He points to a pathetic stalk of grass. I raise my eyebrows and he gets a
sorrowful look on his face. “Lopsided Indian Grass,” he says, as if he’s
talking to a moron. Which, in a way, he is. For the next ten minutes everybody’s
crowded around this little stalk of grass, talking about its hairs and glands
and veins. I’m watching the road. Botanists can look at a single plant for a
very long time. People, I think I’ll sit over here by the monument and take a little
nap while you count hairs. Wake me up when you want to see the mountaintop.”
[editor’s note: several hours and paragraphs later, Janisse is
converted…]
“Have you ever seen smarter people?” my husband says on the
way home.
“Never,” I say. “Seriously. I wish I knew a fraction of
what any one of them knows.”
“I had a really good time,” he says.
So did I.