Saturday, June 11, 2016

Ramble Report June 9 2016



Today's Ramble was lead by Linda Chafin.
Here's the link to Don's Facebook album for today's Ramble. (All the photos in this post are compliments of Don.)
Today's post was written by Dale Hoyt and Don Hunter.

Nineteen Ramblers met today – a cool summer morning!


Announcement: Hugh and Carol will be back in Athens on Tuesday, June 21st. They and Linda will be honored at a reception and book signing at the Garden, starting at 6:30 PM. They might be able to attend the Ramble on Thursday, June 23rd. Carol is reported to be much better and walking without a cane! That Thursday evening there will be a Cafe Au Libris author event at the Athens Regional Library, 7:00 to 8:00 PM, with Hugh, Carol and Linda, so if you missed an earlier opportunity for them to sign your book this would be your last chance. (You did purchase the book (Field Guide to the Wildflowers of Georgia), didn't you?)


Today's reading: Dale read an excerpt from Alison Hawthorne Deming's essay, Field Notes on Culture, Biology and Emergence, in Zoologies, 2014, Milkweed Editions, pp. 235-237. (Note: she was this year's Georgia Review Earth Day speaker here at the Botanical Garden on April 21.)


On a 2008 visit to the Cape Cod National Seashore I heard a young naturalist speak about the condition of the piping plover, a species that nests on the beaches in May and June. I'd become interested after walking there and finding areas roped off for "bird use," where plovers had scratched out tiny basins in the sand in which to lay eggs perfectly camouflaged by the sand grains. The parent plovers worked the tidal wash for prey; a pair of turkey vultures scanned the shore for a shot at cleaning up. On Cape Cod this nesting behavior stirs up controversy akin to the trouble roused in the Pacific Northwest by the northern spotted owl. Select bumper stickers boast "Piping Plover: You Can't Eat Just One" and "Piping Plover Tastes Like Chicken."
Cape Cod fishermen pay dearly for off-road permits to drive their Cherokees and Rams along the beach and surfcast for bluefish and striped bass. Their beach roads coincide with the nesting ground. So the fight is onbirds versus menthough in truth the fight is between one group of citizens and another. I don't see why moderation cannot be a guide here. That appears to have been the course taken by the U.S. National Park Service with its gracefully worded sign, "Bird Use Area," which prods the visitor to consider the motto "Land of Many Uses" as incorporating the interests of species other than our own in our policies.
The lecturer, a young AmeriCorps volunteer doing noble service on behalf of ecological integrity, had been trained to foster audience participation. What I wanted were the facts, the latest research, details about what was at stake for the plovers and how they were doing against the human competition for beach space. But I bowed to the process, with one random half of the audience assigned to the "pro" plover position and the other half to the "con." I was among the pros. No contest in my mind, though I could not get anyone in my group to acknowledge that "all life forms are sacred" was an argument worth holding up to the policy fray. The cons argued "Why interfere with the natural process of evolution?" holding forth that since we are the dominant predators and since we have paid good money for our off-road-vehicle permits, it is our right to unseat the nesters.
Our lecturer floated between the two groups. One of our pro colleagues, wanting to find something tangible to hold up against a fishing license, asked her, "Do they have a purpose? I mean, it would be so much easier, if the plovers had a purpose."
Like what, I wondered? Pharmaceutical production, or mosquito control, or the higher purpose that the religious see in life? I know some people see in the science story a life without direction or ethical dimension. Why are their actions what they are? What should their actions be? The facts of life do not answer and the silence looms. I am not among such people. For me, as for my mother, the facts of life are enough of a miracle to induce religious feeling and a sense of purpose.
"No," our guide confided apologetically to the plover pros. "That's the hard part. They really don't."
I wanted to take her by the shoulders and shake her loose from this capitulation to the forces of doom, but I understood that my role here was not to be the hard hat but to understand how very far my sympathies lay from the general drift of public sentiment.
"Of course they have a purpose," I shouted into my inner megaphone. "Their purpose is to be piping plovers and to make more piping plovers! That's a sacred calling. Life is its own purpose." I remained silent, considering how terribly well my own species had followed the dictates of this imperative to make more of itself. And I sat in the sadness that the argument was not at all a simple one for this random gathering of tourists assembled at the National Seashore on a May afternoon in the first decade of the twenty-first century. If everything is sacred, then how do we know which interests to protect? Our moral philosophy is not yet sufficient to give us clear guidelines.


Today's route:
From the Arbor we took the cement walkway to the Dunson Native Flora Garden, then through the DNFG to the power line right-of-way, which we took to the river. Then right on the White trail to the trail leading to the Mimsie Lanier Center for Native Plant Studies from which we "hot-footed" it back to the parking lot.

On the way down the walkway from the Arbor we passed an Eastern hemlock. This species has been one of the dominant trees throughout the Southern Appalachian forests but in the last 15-20 years it has been under attack by an imported pest: the Hemlock wooly adelgid, a native of Asia. Adelgids are related to aphids and have a similar life style. They feed on the host plant by plunging their sucking mouthparts into its tissue, like a vampire with a straw. Once they have found a host they begin reproducing parthenogenetically (reproduction that does not require males; asexual reproduction). This mode of reproduction enables them to increase rapidly in numbers and the combined activity of hundreds of thousands of adelgids kills the host tree in as little as a year or two.
Hemlocks are a keystone species, a species that dominates and affects the habitat of many other species in their environment. When growing beside mountain streams their dense shade keeps the water cool and the needles that fall from the trees alter the pH of the water, making it more suitable for trout. When these trees die the entire aquatic ecosystem is affected.
Currently only two treatments for adelgids are possible: aerial spraying, which is not very effective, and injection of individual trees with an insecticide, which is expensive and must be repeated. Injection is something that homeowners can do to save a few trees on their property, but is not a practical means of control for the millions of Hemlocks growing in wild forest ecosystems.
There is a beetle in Japan that feeds on adelgids. It is currently approved for biocontrol usage by the USDA, but many problems stand in the way before it can be used: it must be propagated in sufficient numbers to control the adelgid, it should be capable of establishing itself in nature, and there should be no undesirable side effects from its release North America. Until those obstacles are overcome we can only stand by and watch while another grand American tree teeters on extinction.

Across from the hemlock is a large Bottlebrush buckeye with many flower buds that have not opened yet. It has sent up a large number of stems that are spreading across the surrounding area. This species is planted elsewhere in the garden – in the Heritage Garden and in the Rain Garden on the drive in from Milledge Ave.

In the Dunson Native Flora Garden (DNFG) Black cohosh is still blooming. For some mysterious reason Don and Linda both smelled the plant and announced that it smelled like corn meal.

I'm going to depart from the usual chronological approach in this blog and organize what we saw around some common themes. In addition, unless there is something interesting to say about we see I'm just going to list them in the Summary of Observed Species with no further mention.

Invertebrate animals:

George was our eagle-eye today (as he often is). At the Arbor he noticed two Ginkgo leaves that were sewn together by strands of silk. When we pulled them apart it there was a tiny silken purse, perhaps a cocoon or a spider egg sac.

George also spotted two large snails on the rock wall next to Linda as she was telling us about the Hemlocks.

Golden ragwort leaf with leaf mine
In the DNFG the Golden ragwort is long past blooming and most of their dandelion-like seeds have blown away and the flowering stalks have withered away. All that remains are the basal leaves that will persist through the winter to produce next spring's flowers. Many of these dark green leaves have been attacked by leaf miners, insects whose larvae feed on the lush green tissue of the leaf between the upper and lower leaf epidermis. Their feeding activity produces a clearly visible track as they wander through the leaf. As they grow in size the trail they make gets wider, so you can see where they began and where they end. The vast majority of leaf miners are either flies or small moths; over 10,000 leaf mining species have been described world-wide. When the larva has reached the size necessary for metamorphosis it either remains in the leaf or eats its way out and drops into the leaf litter below. There, in the leaf or in the leaf litter, it forms the pupal stage of development. The insect may emerge shortly thereafter or they may overwinter and emerge the following spring, beginning the life cycle over again.

Oak apple gall
Ronnie found something in the DNFG that we haven't seen in a while: an Oak apple gall, usually found on white oaks. This was an old one, probably from last year. The gall is formed when an insect (in this case a wasp) lays an egg on the leaf. Something the larva produces when the egg hatches causes the leaf to form this large, spherical, almost hollow structure. Suspended inside in the center is the wasp larva, far enough away from the surface that only parasitoids that have a long enough ovipositor (an egg laying structure) can reach it.

Large milkweed bug
At the bottom of the DNFG Don found a Large milkweed bug on the Purple milkweed.

Eastern Leaf footed bugs
On the yucca nearby there was a congregation of mating Eastern Leaf footed bugs. During the Ramble last Thursday, the yuccas were full of full, of beautiful flowers. Among the crowd of mating bugs those with sharp eyes found tiny, orange bug nymphs. Whether these are the young of the Leaf footed bugs we do not know.

At the edge of the path in the power line ROW we spotted a basking Widow
Widow Skimmer dragonfly
skimmer dragonfly
. Usually very wary, this one allowed us to approach closely before flying away. Many of the Ramblers were speculating about the color pattern on the wings. Some thought that it made the dragonfly look like a butterfly and wondered if it were actually mimicking one.

When you start to pay closer attention to the natural world it is normal to be curious about the things you see. Why does the dragonfly have dark patches at the base of its wings? Why does a wingstem have "wings" on its stem? Often there are no answers to such questions because we know so little about the organisms we share the earth with. Much of the time the answer offered is a "Just so story," a more or less plausible story that could account for the feature in question. But it remains a story if it is not tested in some way. A plausible story must remain an untested hypothesis until someone can devote the time and effort to testing it.

Nearby the dragonfly was a basking Pearl crescent butterfly that was more skittish than the dragonfly and flew away before many of the ramblers could see it.

Japanese beetle
Once again Ronnie found another interesting insect, a Japanese beetle, an introduced garden pest that many Ramblers may be familiar with. It resembles a June bug, but differs in several ways. It has a metallic coloration that shifts and changes, depending on your angle of view. This is because the color is structural and not due to any pigments. It is like the color of an oil slick on water, caused by the way light waves are diffracted from the beetle's surface. Another characteristic is the hind legs: when disturbed a Japanese beetle holds up its hindmost legs so that they point upwards, making a V shape. Japanese beetles are in the Scarab family, as are the June bugs that bump against your window screens at night. Both kinds of beetles lay their eggs in the soil and the larvae, called grubs, feed on the roots of grasses and other vegetation. Only when they become numerous do they do any significant damage. But adult Japanese beetles are also voracious consumer of vegetation. If their population is dense they can cause considerable damage to garden vegetables and ornamentals.

Other animals

Someone spotted a "blue-tailed skink" on a tree trunk. Without having the animal in hand it is very difficult to precisely identify it because separating the species requires finding small differences in the scale patterns. There are three different skink species with blue tails in the Athens area. Only juveniles have the yellow stripes and blue tails. As they grow older the body color becomes grayish brown and the yellow stripes fade, as does the blue tail color. When mature the males of all three species develop reddish-orange coloration on the head and jaws. This coloration is especially prominent during the breeding season. One of the three species climbs about in trees (is arboreal) and for that reason I think the one we saw was a Broad-headed skink. The other two species are the Five-lined skink and the Southeastern five-lined skink. The latter two species are found primarily in the leaf litter or under rocks and logs, almost never climbing trees.

What is the difference between a skink and a lizard?
A skink is a kind of lizard. There are three commonly seen lizards in the Athens area: skinks, fence lizards, and the Green anole (also known as the American chameleon). Anole can be pronounced either Ah-knoll or Ah-know-lee). Skinks are smooth scaled and can't change color (except as they age). Anoles have granular scales and can change color from green to brown and vice versa. Male anoles have a flap of skin under their chin that is colored red and can be displayed like a fan when they tip their head up. Fence lizards are usually brown, with a darker pattern on their back. They are flattened and have rough scales. They typically are seen on fence posts, tree trunks or rocks. Mature males have blue throats and blue patches on the sides of their abdomen.

Fruits

All those flowers that we saw earlier this year have disappeared, to be replaced by developing fruits. Botanically speaking, a fruit is "a mature ripened ovary (or group of ovaries), containing the seeds, together with any adjacent parts that may be fused with it at maturity." (Raven, et al., Biology of Plants, 6th ed., 1999.) This definition covers all the things you commonly think of as fruits and then some. For example the "seeds" of Ashes and Maples are really fruits; the seed is contained within the wing-like structure which is part of the ovary.

Mayapple fruit (aphids on the stem)
A few of the Mayapples in the DNFG have fruits, the only edible portion of the plant (when it is ripe).

Painted buckeye fruits
One of the Painted buckeyes in the DNFG is now bearing fruit. It will double in size when fully matured.

Goldenseal with fruits
Also bearing fruits in the DNFG is Goldenseal. It bears aggregate fruit, like raspberries; single seeded fruits clustered together to make a single unit. It is bright red when ripe, encouraging birds to eat it and fly away to deposit its seeds elsewhere when they pass through the digestive tract

Dwarf pawpaw fruits
Even the Dwarf pawpaw has produced some fruit.

Although this is not a big year for Hophornbeam fruits we did find one in the DNFG that had an infructescence (a collection of fruits) that looks like that of the Hop vine, which is used in brewing beer.

Sanicle fruits
The sanicle plants in the Dunson garden are now bearing burr-like fruits, usually in triplicate at the ends of stems.

The Curly dock has grown big and tall and the ovaries are developing a dark red brown color, each fruit containing a single seed.

American pokeweed (flowers to left; fruits to right)
The inflorescence of American pokeweed shows the transition from flower to fruit very nicely. The flowers at the bottom of the inflorescence open first and, therefore, are the first to develop into fruits. The younger flowers toward the top open later, so they are awaiting pollen while the older flowers toward the base are becoming mature fruits.

Green ash samaras; dark brown seed is at one end.
On the trail toward the Mimsie Lanier Center we found the fruits of Green ash scattered all over the ground. Like that of its Maple relatives, the Ash fruit is called a samara. The seed is surrounded by a broad flat wing that develops from the wall of the ovary. This wing enables the fruit to be carried away from its parent tree by the wind. The fact that we had trouble locating the parent tree indicates how effective this mode of seed dispersal is

Plants:

In the DNFG we found a Cinnamon vine growing in a clump of Christmas ferns. This is not a native plant and should be removed from the Dunson garden.

A Jack-in-the-pulpit with five leaflets instead of the more typical three was seen in the DNFG. We have seen this variant numerous times elsewhere in the garden. Linda observed that she has never seen one of these five-leaved forms with a flower. Carol Gracie, the author of Spring Wildflowers of the Northeast, says (p. 104): "Rarely, an aberrant plant with more than three leaflets is found." Although not common, we see plants with five leaflets to often to call them rare.

When the American sycamore initiates spring growth last year's bark is sloughed off in large patches due to the increase in the tree's girth. Don picked up one large piece of bark and found the grazing pattern of slugs in the algae that grow on the bark.

Oakleaf hydrangea; showy white bracts, tiny flowers below bracts
The prominent white "flowers" of Oakleaf hydrangea are like the Dogwood "flowers" – they are bracts, not petals. Bracts are modified leaves and in the case of Dogwoods, Poinsettias and the Oakleaf hydrangea they function like petals – to attract insect pollinators. The tiny flowers of the inflorescence are found below the showier bracts.

Lizard tail inflorescence
The Garden has worked hard to get wetland species established in the little basin in the lower section of the Dunson Garden and that hard work has produced its reward: Lizard tails are blooming in profusion and a single Green pitcher plant has put up a blossom. (Why this inflorescence resembles a lizard tail is a mystery. Whomever made up the common name had never seen a lizard.)

Last week's puzzle has been solved. The Coneflower we couldn't confidently identify is Smooth purple coneflower, an rare and endangered species found only in two counties of NE Georgia.

Extrafloral nectaries are nectar-secreting structures that are not located in flowers. Many plants have them and their function was a mystery for many years. If the function of nectar is to attract pollinators, why should a plant produce nectar anyplace besides a flower? It turned out that nectar doesn't just serve as an attractant for pollinators. It also attracts bodyguards – ants. It has been shown that ants protect plants with extrafloral nectaries from herbivorous insects. When ants are excluded from such plants they suffer larger amounts of damage to their leaves and fruits. In the course of searching for extrafloral nectar the ants also attack and eat insect eggs and larvae that the encounter. It's a win-win situation for both participants!

Maryland senna compound leaf
In the power line ROW Maryland senna is not yet flowering. The plant has pinnately compound leaves with around eight pairs of leaflets and is often but not always without a terminal leaflet. At the base of each leaf is a pair of extrafloral nectaries.

Power line Right-of-Way:

Indian heliotrope; scorpioid inflorescence
We found several purple flowered Indian heliotrope near the gravel parking area, as well as near the Mimsie Lanier Center. At both locations they were growing in open grassy areas. The heliotope has a scorpioid inflorescence. This refers to the way in which the flowering stalk develops like a fern fiddlehead, tightly coiled. As it matures it uncoils and at one point look something like the curved tail of a scorpion, which is the meaning of the name.

Further down the ROW we noticed many of the same galls we saw last week on the Tall goldenrod: apical leaf galls and spherical galls on the stems. On one plant there were two spherical galls only a few inches apart.

As you progress down the ROW you pass the marshy area were we found frog eggs this spring. Here we see sedges and rushes growing in profusion which always induces someone to repeat the rhyme that helps us determine which is which:

Sedges have edges,
Rushes are round,
Grasses have joints,
All the way to the ground.

A lone example of Poison hemlock was seen growing among the vegetation east of the ROW. This species is in the carrot family which has a characteristic floral growth pattern called an umbel. The tiny flower stalks all grow from a common point like the ribs of an umbrella. The ends of the stalks bear tiny flowers and all the flowers of the umbel form either a flat surface or a convexly curved surface. In some cases each stalk terminates, not in a single flower, but in another umbel of tiny flowers (Queen Anne's lace).

White Trail and Mimsie Lanier Center Connector Trail:

We stopped to admire a HUGE (sorry, Donald Trump) Trumpet creeper vine. It must have been growing here for many years to reach its size.

Cottonwood leaf
We saw many Cottonwood leaves on the ground. Their petioles are flattened and some had galls near where the leaf blade arises. The flat petioles are characteristic of the poplar genus (Populus), and cause the leaves to tremble or quake with even a slight breeze. The poplar genus includes Cottonwood, Quaking Aspen and true Poplars, but NOT the so-called Tulip Poplar (AKA Yellow Poplar) which is in a completely different plant family.

We found Lady fern near the deer fence. The latter had been heavily browsed by deer, which is surprising because ferns are thought to be heavily protected by their distasteful and toxic chemicals. But deer probably don't read the same books and don't any better.

Mimsie Lanier Center for Native Plant Studies:

In the open area between the deer fence and the center all of the following were seen blooming: Carolina desert chicory, Tall coreopsis, Indian heliotrope, Field madder, Sow thistle, Brazilian clover and Butterfly weed.

To learn how Sow thistle got its name click here and scroll down.

Butterfly weed
Butterfly-weed is unusual in that is the only milkweed that doesn't have milky sap. The milky sap contains latex, a natural rubber compound, as well as a number of nasty compounds that make the plant poisonous or distasteful to many herbivores. Some beetles, bugs and the caterpillars of some butterflies and moths are able to feed on the plant, however.
Milkweed flower are, except for Orchids, the most complex. Pollen is not loose as in most other flowering plants. It is packaged into containers called pollenia, which are positioned so that an insect visiting the flower for nectar will contact the pollenia with its leg. When the next flower is visited the leg must slip down into contact with another part of the flower to be scraped off. Consult p. 46 of Linda's new book for more details.

Confusion about butterflies and their food plants. The term "food plant" is ambiguous when referring to butterflies because the adults and the caterpillar feed very differently. A caterpillar chews off pieces of its food plant and swallows them. The adult butterfly cannot feed in this way. It has a tubular mouthpart that works like a straw; it can only suck up liquids. For most butterflies this means they feed on nectar produced by a flower. (Some adult butterflies do not consume nectar, instead they feed on sap flows, fermenting fruits or even animal feces. In all these cases they can only feed on liquid nourishment.) Adult butterflies usually are not restricted to a single source of nectar – they can sip nectar from any flower that their "tongue" can reach. Adult Monarchs, for example, can obtain nectar from thistles and many other flowers in addition to milkweeds. But Monarch caterpillars are restricted to eating milkweeds. So when it is said the Monarchs are restricted to feeding on milkweeds it means that the Monarch caterpillar can only feed on milkweeds. It would be clearer if there was a different term to use and there is. The term "host plant" means the plant species that the caterpillar can feed on. So when we say that milkweeds are the host plants for Monarch butterflies it means that Monarch caterpillars feed exclusively on milkweeds.

Chinese wingnut tree
At the edge of the field our attention was caught by a large Chinese wingnut tree with a huge number of long racemes bearing seeds. 
  
 SUMMARY OF OBSERVED SPECIES

Common Name
Scientific Name
Shade Garden
Eastern hemlock
Canadian hemlock
Tsuga canadensis
Common garden snail
Cornu aspersum [?]
Bottle brush buckeye
Aesculus parviflora
Dunson Native Flora Garden
Black cohosh
Actaea racemosa
Golden ragwort leaf mines
Fly (Diptera) or Moth (Lepidoptera)
Cinnamon vine
Dioscorea oppositifolia
Ashes magnolia
Magnolia ashei
Jack-in-the-pulpit
Arisaema triphyllum
Goldenseal
Hydrastis canadensis
American sycamore
Platanus occidentalis
Leatherwood
Dirca palustris
Oakleaf hydrangea
Hydrangea quercifolia
Foamflower
Tiarella cordifolia
Sanicle
Sanicula canadensis
Dwarf pawpaw
Asimina pygmea
Mayapple
Podophyllum peltatum
Painted buckeye
Aesculus sylvatica
Lizard tail
Saururus cernuus
Green pitcher plant
Sarracenia oreophila
Stoke's aster
Stokesia laevis  
Horsetails
Equisetum hyemale
Hophornbeam
Ostrya virginiana
Eastern leaf footed bug
Leptoglossus phyllopus
Longleaf pine
Pinus palustris
Smooth purple coneflower
Echinacea laevigata
Large milkweed bug
Oncopeltus fasciatus
Common elderberry
Sambucus nigra canadensis
Power line right-of-way
Widow Skimmer dragonfly
Libellula luctosa
Pearl crescent
Phyciodes tharos
Maryland senna
Senna marilandica   
Turnsole/Indian heliptrope
Heliotropium indicum
Curly dock
Rumex crispus
Japanese beetle
Popillia japonica
Tall goldenrod
Solidago altissima
Poison hemlock
Conium maculatum
White trail
American pokeweed
Phytolacca americana
American toad
Bufo (Anaxyrus) americanus 
Juvenile broadhead skink
Eumeces (Plestiodon) laticeps
Turkeytail mushroom
Trametes versicolor
Mimsie Lanier connector trail
Trumpet creeper vine
Campsis radicans
Green ash
Fraxinus pennsylvanica
Cottonwood
Populus deltoides
Sensitive fern
Onoclea sensibilis
Stinging nettle
Laportea canadensis
Mimsie Lanier Center field
Lady fern
Athyrium filix-femina
Carolina desert chicory
Pyrrhopappus carolinianus
Tall coreopsis
Coreopsis tripteris
Field madder
Sherardia arvensis
Sow thistle
Sonchus oleraceus
Brazilian clover
Richardia brasiliensis
Butterfly weed
Asclepias tuberosa
Chinese wingnut
Pterocarya stenoptera
Spiderwort
Tradescantia sp.
Mimsie Lanier Center roadside
Sensitive brier
Mimosa microphylla
Wild onion
Allum sp.
Paved Road (between Dunson Garden and ROW)
Leather vasevine
Clematis viorna
Sundrops
Oenothera fruticosa 


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