Friday, June 13, 2014

June 12 2014 Ramble Report



Eighteen ramblers met today on what started as a foggy morning but the fog soon burned off. Our decision to start the rambles earlier this summer seemed to be the right one. The day didn't start heating up until we had finished our walk.

Don Hunter's facebook album of the ramble can be viewed here.

At the side of the parking lot several people noticed a hawk sitting in a nearby
One-legged hawk?
tree. It is possible that this is the same hawk we have previously seen in the power line. It seemed unperturbed by the cluster of people staring at it. The group moved off to begin the ramble and the Hawk followed them, flying to another nearby tree. It is unknown which of us smelled like a small rodent. I've included Don's photo of the hawk in the hope that one of our bird-knowledgeable ramblers can confirm its identity (Red-tailed or Red-shouldered). Another thing to notice is that it appears to have only one leg. Let us know if you think the bird is simply resting on one leg with the other tucked out of sight.



UPDATE!!
Information from Chuck Murphy indicates that the hawk is an immature Red-tailed Hawk. Chuck further provided two photos of the same individual, taken by Heather Lickliter. They clear up the mystery of the missing leg:
There it is!

Missing the left leg?















Now you see it!
Fellow Rambler Ed Wilde took two pictures of a Red-shouldered hawk in
Now you don't!
his front yard last year. Guess what! First it was on two legs and then one! 


I've posted a possible explanation for the one legged behavior. Click here to read it.

The reading was provided by Silvio Curtis and is from the Ursula K. Le Guin book Always Coming Home, pp. 51-52, and can be found here. 

Our route today was through the International Garden, taking the walkway on the left side (closest to the conservatory), and then through the hop vine arbor, past the Paw Paws to the Orange Trail connector; then down the connector and over the bridge to the Orange Trail. Then left on the Orange Trail to return via the upper parking lots.
Before departing the Arbor I passed out an 8-page minibook with drawings of seven common ferns that can be seen on the Orange Trail. There were not enough copies to go around so people shared.

In the patch of native plants growing by the International Garden entrance there were only two species still blooming, the Virginia Spiderwort and Stoke's Aster, the latter looking a little bedraggled from last night's heavy thunderstorm. The Blue false indigo bushes have swollen bean pods.

In the Garden proper we stopped near the Zinnias to talk about one of my pet peeves. Plant breeders "improve" plants like Zinnias by breeding for larger flowers with more petals. Zinnias are composites, which means that what most people call the zinnia flower is really a compact group of small florets, similar to a daisy. Originally only the outermost ring of florets had the broad, brightly colored petals (these are called ray florets) and the remaining florets (the disk florets) lacked a prominent petal. But those disk florets produced the nectar that was why the butterflies visited the Zinnias. In fact, many people planted zinnias in their garden because they attracted butterflies. The effect of the breeders efforts was to create a plant in which many of the disk florets were replaced by ray florets. This made the flower head larger and showier, but did so at the expense of nectar production. Such flowers are not as attractive to butterflies or other nectar-loving insects, like bees. So, as it so often happens, form is valued over function. The modern zinnia will still attract butterflies, but not like the old-fashioned varieties. So if you plant Zinnias because you want butterflies to visit your garden you would be better off to seek out the old style of zinnia, one without all the increased petals.

We also noted several kinds of Yucca at this point in the garden. Many different yucca species are called Spanish Bayonet. The real Spanish Bayonet can be found growing in Big Bend National Park in Texas. There are large stands of them there and they are tall, from 8 to 10 feet in height, exclusive of the flowering stalk, which can add another 10 feet and 150 pounds to the plant.

Fruit of Hop vine
Then it was on to the Hop arbor where the Hop vines are growing. I pointed out the Hop fruits that are used to flavor beer and are also similar in appearance to the fruits of the Hop hornbeam tree. 2012 was the last year that the Hop hornbeams in the Garden produced a lot of fruits, so search your memory for what they look like.

Further along the walkway we pass a group of Paw Paws. These are moderately tall trees, but only two fruits were seen.

Just beyond the Paw Paws there was a strand of spider silk stretched across the walkway just above our heads. A tiny spider was traversing it and the question arose: how did the spider get the silk across the sidewalk that high up? You might have noticed that when you go outdoors early in the morning that you often feel strands of silk brushing against your bare arms. These are from "ballooning" spiders. Tiny spiders climb to an elevated position, tip their abdomen up and release a strand of silk from their silk glands. The silk thread is so light that a gentle breeze can catch it and carry it away. If it comes in contact with another surface it will stick and the spider can use that line as a walkway to start a web or simply cross an open area.

In the "Physic" garden are plants that were used for medicinal purposes. This garden is planted with the varieties that a well know local physician, Dr. Lindsey Durham, who lived in Scull Shoals, GA, had in his own garden. Growing here are: Colic root, Weeping redbud, Rattlesnake master, Beebalm, Feverfew, Wild quinine, and Common mullein. Scull Shoals is now a ghost town in the Oconee National Forest. To learn more about this important community in Georgia history and more about Dr. Durham, click here.
Hugh and Franklinia
Growing in a large pot is a specimen of Franklinia, the plant first discovered by John and William Bartram on the Altamaha River near Darien, Georgia, in 1765. It was later described as a new species by William Bartram and last seen in the wild in the early 1800s. It now survives only in cultivation.





Nearby is a small house filled with paper tubes about a foot long and 1/4 inch
A "house" for solitary bees
in diameter. This is a "house" for solitary bees. Unlike honey bees solitary bees do not live in hives composed of thousands of other bees with division of labor among them. Solitary bees are not social. Each fertilized female constructs her own "nest" and provisions it with food for her young. There are many different kinds of solitary bees but many of them construct nests in the same manner. They excavate a tunnel in the ground or in the end of a twig or broken stem. She then gathers pollen and nectar to place in the bottom of the tunnel, lays an egg on the mixture and then seals the chamber off using some environmental material like mud or cut off pieces of leaves or chewed up plant fibers. If the tunnel is long enough she will continue making and provisioning chambers until the tunnel if filled with her future offspring. Then she dies. Inside the chambers the eggs hatch and the grub-like larva feeds on the pollen-nectar mixture until it grows large enough to pupate. The pupae overwinter and the following spring the adult bees emerge from their chambers, mate and repeat the process.

Capped tubes filled with bee larvae
Some of the paper tubes in the picture to the left have already been filled with bee larvae and capped with Georgia red clay. An interesting detail is the way sexes are determined in Hymenopterans (ants, bees, wasps and their relatives). Other tubes appear to be capped with plant fibers -- this may be a different species using the tubes. The female controls the sex of her offspring. She stores sperm from her mating and uses it when she wants to. If an egg is fertilized it develops into a female. (In a honey bee colony it will develop into a sterile worker bee.) An unfertilized egg develops into a male. In most hymenopterans the males only role is to mate with a female. When a solitary provisions a lot of cells in a long tunnel she holds back sperm when producing the eggs for the last few cells so they will develop into males. Since these cells are closest to the end of the tube the males emerge first. The last bees to emerge are the females produced from the earlier, fertilized eggs laid in the back of the tube. They are met by a crowd of males flying around the tube opening, eager to mate.
Wasp seeking bee larvae? Yum, yum!!
All is not safe in a capped tube though, as the photo to the left shows. A wasp has discovered an uncapped cell (or uncapped it) to get some tasty bee larvae to feed to its offspring.

Solitary bees are vital parts of the ecosystem. They are often more efficient at pollination than honey bees and more effective. In an apple orchard pollinated by a few dozen solitary bees can produce more apples of higher quality one hive of thousands of honey bees. In addition, many native plants that are ignored by honey bees are reliant on solitary bees for their pollination services. Modern industrial agricultural practices destroy the habitat necessary to support solitary bees, greatly risking their extinction and that of the native plants that depend on them.
American Wisteria
Growing on the bridge is a native species of wisteria, American Wisteria, which is still in bloom. This species is not invasive, unlike the Chinese Wisteria that can quickly escape from cultivation and spread to adjoining tree.

Hugh also pointed out a Virginia Creeper vine and pointed out that its 5 leaflets clearly distinguish it from Poison Ivy, which has only 3 leaflets. Many people confuse the two. Virginia Creeper is an "aggressive" plant, meaning that it easily will spread out of its desired place in the garden and shade out other plants. But it is not invasive. Invasive plants are aggressive but not all aggressive plants are invasive.
We also encountered a planting of a Beautyberry cultivar that was loaded with blossoms. If each of these sets fruit the shrub will be laden with beautiful purple berries in the fall. A couple of Butterfly Peas were also seen growing by the sidewalk.

The pieces of wood that border the sidewalk near the meditating woman statue are being rotted by a Turkey Tail-like mushroom. It has pores on the lower surface from which the spores are released. The pores are found on true Turkey Tail mushrooms, as well are other fan-like wood rotters.

Jack in the pulpit fruits
Nearby Hugh spotted a Jack-in-the-pulpit with developing fruits. They are presently green but will turn a brilliant crimson by fall.

We stopped to examine the new growth of a Sourwood. At this time of year the new growth of trees is usually still green in color and you can see how much they have elongated in the 1-2 months since the buds have opened. The rate of growth is surprising because it is seldom noticed by most people.

We found our first fern which turned out to be a Christmas fern that had not yet developed fertile fronds. This was the first of many Christmas ferns that were to be seen along the Orange connector and the Orange Trail itself.
Rattlesnake fern with fertile frond in center
Nearby was a Rattlesnake fern. We could be confidant of our identification because it had the fertile frond emerging from the stipe at the level of the fronds. The other similar fern, Grape fern, does not develop its fertile frond until later in summer.

On the Orange Trail:
A general question:
We found very few plants in flower today, a sharp contrast to the early spring when all the spring ephemerals were blooming. The explanation usually given is that when the trees leaf out there is not enough sunlight reaching the ground to permit the development of seeds, so flowering plants are few and far between. But why, then are ferns so abundant? Is it because ferns do not produce seeds? They may produce only spores, but they produce massive quantities of them. I don't know how much energy a fern diverts into spore production, so I can't answer that question, but it has been bothering me for some time. Perhaps you can come up with some ideas. If you do, put them in the comment box at the bottom of this post.

A group of Broad beech ferns
Ferns seen: Christmas Fern, Ebony spleenwort, Broad beech fern, either Rattlesnake fern or Dissected Grape fern, Lady fern. The Rattlesnake and Dissected Grape ferns appear very similar to one another. If there is no fertile frond present I can't tell the difference. So those we saw are either Rattlesnake ferns that have not yet produced a fertile frond or Dissected Grape ferns that will develop their fertile fronds later in the summer.

The only wildflower we noticed on the Orange trail was White Avens; a flowering shrub, Elderberry, was also seen. Other plants noted were Catbrier, Trumpet vine, Wild Yam and Bedstraw (also called Cleavers or Catchweed because its bristles cause it to cling to the fur and clothing of passing mammals. It's called Bedstraw because it was used to stuff mattresses by early pioneers.

Beech blight aphids in close up
One of more entertaining sightings was the cluster of Beech blight aphids found on a lower branch of an American beech tree. These insects suck the juices from the Beech twigs and reproduce very rapidly, producing a very large colony of aphids. Each one secretes a waxy substance that covers much of its body and makes the group look like little tufts of cotton glued to the twig. When disturbed by shaking the branch they immediately started to boogie-woogie, much to our entertainment. You can find more information and a short video of the dance here.

Mushroom sex:
The spore-producing surface of Split gill mushroom
the gills split toward the edge of fruiting body


On one of the rotting logs we saw some Split gill mushrooms. I made the casual remark that this fungus has thousands of different sexes. That immediately tweaked the curiosity of a number of ramblers who deluged me with questions. I'll try to answer these and, if you're not interested in mushroom sex, you can skip the rest of this post.

I've tried to explain this material without making a lot of assumptions about your previous knowledge. A more technical description of sex in Split gill fungi can be found here on the web.

First, though, you need to know (or remember) that mushrooms are the fungal equivalent of flowers. Just as a flower is produced by a plant, a mushroom is produced by a fungus. In flowering plants the body (roots, stems, leaves) of the plant provides the nutrients to produce the flowers and, ultimately, the seeds. In a mushroom-producing fungus the part corresponding the roots, stems and leaves is the mycelium. It looks very different from a plant. You've seen a mycelium before. When bread gets moldy the fine, white threads you see surrounding the colored molds are the mycelium of the mold. Similarly the wood-rotting mushrooms have fine threads the penetrate everywhere in the wood, secreting digestive juices that break down the wood fibers and then absorbing those digestive products. To produce a mushroom the mycelium must acquire enough energy from its log (or whatever it is rotting). But that is not enough. It has to meet and fuse with a mycelium of the same species but a different sex.

So most mushrooms are the result of a sexual act. But mushrooms do it a lot differently than other organisms. There is nothing like easily recognizable male and female fungi, and a fungus doesn't mate with just any other fungus. Fungal sexes are separated into what are called "mating types." In order to produce a fruiting body (a mushroom) the mycelium of one individual must fuse with the mycelium of a different mating type. The mating types are not visibly different. They can be determined in the laboratory by whether or not two mycelia can fuse. If they can't, they are the same mating type. If they can, they were different mating types and the fused portions will go on to produce a fruiting body. A Harvard botanist, John Raper, discovered that there weren't just two mating types in the Split gill fungus, but many different ones. He further discovered how the mating type was genetically controlled and that the mating type genes were highly variable. So a Split gill can mate with any other type of Split gill except one that has the same mating type. With that knowledge he estimated that, worldwide, there were 20,000 different mating types to be found in Split gill fungi. One species, twenty thousand sexes!

Mushroom sex differs in other ways from that seen in plants and animals. In plants and animals when egg and sperm come together their nuclei fuse to produce a single cell. That cell has a single nucleus that contains the chromosomes (and genes) of both parents. Fungi delay the nuclear fusion. Instead, when two mycelia fuse their respective nuclei intermingle in a common cytoplasm. (The fungal cytoplasm is not divided into cells like that of a plant or animal. Instead it is a single cytoplasm within which the nuclei can move about more or less freely. So after the two mating types have joined their mycelia the fungal cytoplasm contains two genetically distinct nuclei. In other words, mycelial fusion is not the same as egg and sperm fusion. It does not result in a single cell with a single nucleus combining the genetic material of both parents. It results in a cytoplasm in which two genetically distinct nuclei coexist -- a special kind of "hybrid" called a dikaryon. (The di- means two; -karyon is a Greek word that refers to the nucleus; thus, a dikaryon is an organism with two different nuclei in its cytoplasm.) The dikaryon mycelium can continue to grow and when the conditions are right it will produce a mushroom. Within the tissues of this mushroom are specialized cells, called basidia, that will produce spores. Within each basidium the two genetically different nuclei fuse and then undergo the same type of division that human egg or sperm precursor cells do, called meiosis. This type of cell division reduces the amount of genetic material by half in each resulting cell. The cells that result from this type of division become spores and are released from the gills of the mushroom by the billions, to drift away on the gentlest of breezes. Those few that land in suitable places will germinate to form a new mycelium that combines the genetic makeup of both parents, except it will have only one or the other mating type. And so the cycle of life continues.

SUMMARY OF OBSERVED SPECIES:

Common Name

Scientific Name
Red-tailed Hawk
Buteo jamaicensis
Virginia spiderwort
Tradescantia virginiana
Stoke’s aster
Stokesia laevis
Blue false indigo
Baptisia australis
Paw Paw 
Asimina triloba
Yuccas
Yucca sp.
Hops
Humulus lupulus
Colic root
Aletris farinose
Weeping redbud
Cercis canadensis 'Covey'
Rattlesnake master
Eryngium yuccifolium
Beebalm
Monarda sp.
Feverfew
Tanacetum parthenium
Wild quinine
Parthenium integrifolium
Common mullein
Verbascum Thapsus
Franklinia
Franklinia alatamaha
Solitary bees
Hymenoptera
Butterfly Pea
Clitoria mariana
American wisteria
Wisteria frutescens
Virginia creeper
Parthenocissus quinquefolia
Beautyberry cultivar
Callicarpa sp.
Turkey Tail mushroom
Trametes versicolor
Jack-in-the-pulpit
Arisaema triphyllum
Sourwood
Oxydendrum arboretum
Redbud
Cercis canadensis
Christmas fern
Polystichum acrostichoides
Rattlesnake fern
Botrypus virginianus
Wild yam
Dioscorea villosa
Old Man’s Beard
Usnea strigosa
Bedstraw
Galium aparine
White Avens
Geum canadense
Elderberry
Sambucus canadensis
Broad beech fern
Phegopteris hexagonoptera
Lady fern
Athyrium filix-femina
Ebony Spleenwort
Asplenium platyneuron
Split gill mushroom
Schizophyllum commune
American Beech
Fagus grandifloria
Beech blight aphid
Grylloprociphilus imbricator
Catbrier
Smilax glauca
Trumpet vine
Campsis radicans