Thursday, May 25, 2023

May 25, 2023

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.

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.

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.
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.

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.

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.

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.


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
Black Cohosh flowers lack petals and rely on dozens of 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.

Tall Thimbleweed, a member of the Buttercup Family, at the entrance to the Dunson Garden

Leaf Miner trails on the leaves of Columbine (left) and Golden Ragwort (right). Good luck finding the origin of the Columbine's trail!

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."

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.
Dwarf Pawpaw fruit
It’s pretty unusual to spot a fruit; they’re typically snagged by squirrels and raccoons before humans find them.

A late-flowering Indian Pink

Daddy Longlegs on Early Meadowrue leaves

A colorful palette of lichens and mosses on the trunk of a Cucumber Magnolia tree
Dale explained the basics of molecular genetics in response to a question by Randall, a new rambler.
photo by Gary Crider
       
Broad Beech Ferns lifting their foxy heads

New York Ferns “burning their candles at both ends”

Lace Bug
photo by Heather Larkin

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....

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.

Fuzzy fruits of Wood Poppy
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.
Spicebush fruits will turn a bright, clear red when ripe.
Painted Buckeye fruits
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.

A Milkweed Bug visiting a Purple Milkweed inflorescence

The small patch of Purple Milkweed
on the western edge of the Dunson Garden is flowering. Although common in several midwestern states, this species reaches its southern extent in Georgia, where it is one of our rarest plants.

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

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.
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.” 

Yucca Moth on a Yucca flower's densely hairy stamen
Photo by Heather Larkin
         
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.