Saturday, May 31, 2014

May 29 2014 Ramble Report

Today 30 Ramblers turned out to enjoy a sunny morning stroll.

All of Don Hunter's photographs of today's ramble can be found here.

Click here to see our three readings commemorating Rachel Carson's 107th birthday which was earlier this week (May 27).

Route: Through the Shade Garden to the White Trail. White Trail to the power line right of way (ROW). Down the ROW to the river. Left on the White Trail to the Orange spur trail. Orange spur trail to White trail back to the arbor parking lot.

About chiggers:
Some ramblers commented on my haute couture this morning (pant legs
Latest Fashion?
tucked into hiking socks).  It's all to avoid chiggers. Years ago I was a field assistant for Henry Fitch, an eminent naturalist now recognized as the father of snake biology. We would go out into the woods and fields of the Kansas Natural History Reservation (now known as the Fitch Natural History Reservation), to capture and mark snakes for future identification. Kansas was a mecca for chiggers and to avoid getting thousands of chigger bites we used a very fine sulfur powder. Henry kept a 5 gallon jar filled with flowers of sulfur on the front porch along with a large hunk of cotton. Every investigator that worked at the reservation always stopped at the jar, dunked the cotton into the sulfur dust and applied it to their pants and socks, tucking the pant legs into the socks to keep the chiggers out. The sulfur acted as an abrasive, wearing holes in the exoskeleton of any tiny chigger that wandered through it. The chigger would then die of fluid loss before it could find its way up to your skin. That's why I dust my ankles with it and tuck my pants into my socks.

Chigger bites are a mistake! The normal host of a chigger is either a reptile or a small mammal. Imagine the disappointment of a small chigger as it finally finds a cozy warm place, pierces the skin, injects a cocktail of digestive juices to liquefy the skin cells and then slurps up the slurry, only to discover it doesn't taste like snake. Ugh! It quickly backs away and drops off. The itching and swelling you experience is your own body's immune system reacting to the chigger spit and the liquefied skin cells. The itching will last as long as it takes for your white cells to clean up the mess. But the chigger has already departed, so painting the welts with clear nail polish won't do anything to speed up this process -- it just makes you feel like you've done something. (My grandmother always told me that the nail polish would keep the chigger from breathing and would kill it.) Calomine lotion doesn't work either. Sometimes itch relief medications will help. The best thing to do is to stop thinking about how much those bites itch! To learn more about chiggers read this publication from the Alabama Cooperative Extension System.

Passing through the Shade Garden we noticed a small Trillium growing next to the walkway. This was not deliberately planted so how did it get here? The nearest source of Trillium is the Dunson Native Flora garden, at the bottom of the hill. So how did the Trillium walk uphill? The solution is probably ants. Ants carry Trillium seeds around and are responsible for dispersing the plants. It's a slow process though. It takes many years for a Trillium to grow from a seed to a plant capable of reproducing itself.

Witch Hazel leaf galls: We stopped along the walkway where two American Witch Hazels are growing. We frequently look at these shrubby trees because of the interesting galls present on the leaves. The pointed growths are caused by aphids that live inside them. Over time the galls don't seem to change size much, but they do change color. Some become hard and blackened and some are damaged, looking like something attempted to open them. Perhaps a bird pecked at them to get at the tasty aphids inside.

Beech leaves: Alongside the White trail is an American Beech with its lower branches growing in the sunlight. It's leaves are thicker and tougher feeling than those of Beeches growing in the full shade of the forest. In this they probably resemble the leaves at the top of the canopy, thicker to resist the sun and reduce water loss. We don't normally get to see the canopy unless we can climb to top of a tree or have a long ladder.

Post Oak:
A few yards over from the Beech is a Post Oak. This Oak has very distinctive leaves -- the lobes are arranged in the form of a Maltese cross, making it hard to confuse with any other oak growing in the garden.

Hophornbeam and masting:
Near the Beech is an Hophornbeam (Ostrya virginiana), a small understory tree. Hophorbeams,like many forest trees, produce flowers in the spring that develop into fruits during the summer. But this particular tree has only one developing fruit. This is the third year we have watched this tree and it failed to produce any fruit last year (2013), but was heavy with fruit in 2012. This irregular pattern of fruit (and seed) production is called "masting," and is common in forest trees (oaks, hickories, beech, etc.) The term comes from the word mast, which is a term used to describe the edible fruits produced by trees. This year is not shaping up to be a mast year for the Hophornbeams. We'll have to wait until fall to see if 2014 is similarly a poor mast year for the oaks and hickories.

Actually, the cause of masting is something of a mystery. You might think that there would be a lot of tree to tree variation in the amount of fruit (seeds) produced, depending on each individuals condition. Trees growing on favorable sites ought to be able to produce lots of fruit every year while those on unfavorable sites might have to nurse their resources for several years before bringing forth a lot of nuts. But masting is synchronous over large geographic areas. No one has definitively determined how this is possible. There are still many secrets in the natural world.

The sumac growing on the White Trail (Shining Sumac, Rhus glabra) has compound leaves. You can usually determine what a leaf is by looking at where it is attached to a branch. The leaf stalk (called a petiole) is usually swollen and a bud is usually visible where the petiole attaches to the twig or branch. If what you think is the petiole is not swollen and no bud is visible the chances are very good that you are looking at a leaflet, not a leaf. Sumacs have multiple leaflets on each leaf. So do hickories, pecans and ash trees.

Redbud and leaf-cutter bees:
Next to the sumac was a Redbud, at tree with simple, heart shaped leaves.
Leaf Cutter bees did this
Many of the leaves on this redbud had semicircular pieces removed, as if something or someone had carefully cut out half-moon shapes from the leaf. The mysterious snipper is a leaf cutter bee, one of the many kinds of solitary bees. Leaf cutter bees construct a nest in a broken twig, especially one that has an easily chewed out core of pith. They hollow out the twig by removing the pith and then gather pollen and nectar to make a kind of bee bread that they put in the bottom of the hollow twig. When sufficient bee bread has been prepared the female bee lays an egg and then flies to a tree with the correct texture leaves and carefully cuts out a semicircular piece from its edge. This is taken back to the nest and stuffed into the twig cavity. If there is enough room in the twig a second nest is provisioned in the same manner. When the twig is full of bee offspring she abandons them and seeks out another twig to provision. Leaf cutter bees are a kind of solitary (non-colonial) bee that are highly efficient pollinators of native plants, better than honey bees. They and other solitary bee species are endangered by habitat loss as well as competition from honey bees which are not native to the United States.

Dandelion Look-alikes:
Blooming in many neglected yards right now are cheerful yellow flowers that many people assume are dandelions. We found some on the power line ROW and a closer examination shows that they are not dandelions. But why? Both dandelions and the not-dandelions grow from a basal rosette of leaves the
Cat's Ear
hug the ground, avoiding the blades of lawn mower herbivores. But dandelions produce a single flower from a single stem, whereas these look-alikes produce several flowers from a single stem. In addition, the flower stem of the true dandelion is tan in color and hollow. When the stem is broken it releases a lot of milky fluid that is quite sticky. The non-dandelion stem is solid and green and produces little or no milky fluid when broken. So what is this non-dandelion? I mistakenly identified it as a Dwarf dandelion (Krigia spp.). Diona corrected me, saying that she thought it was Cat's Ear (Hypocharis radicata). Diona is right and I hang my head in shame. The proof is to look at the flower heads of the plant. Below the yellow petals you will see numerous green pointed bracts that surround the flower base. If there is just a single row of these the plant is a Dwarf dandelion. The Cat's Ear has multiple bracts of different lengths.

Sweeping for insects:
At the power line ROW there are areas with lots of tall grasses. As we walked
Children with nets!
down the ROW I demonstrated the sweep net technique entomologists use to collect insects that normally remain hidden from view. Using a heavy canvas net it is vigorously swept back and forth in the vegetation and then the contents observed. Many small flying insects escape, but the immature stages can't fly and they remain in the net. My sweeps were a little disappointing. The grass was still damp with dew and the net got wet and all the grass seed suck to the cloth, making the insects harder to see. We mostly found seed eaters, both true bugs and weevils (a type of beetle). All were very small and hard to see properly without magnification. Later in the season some of these will have grown enough to be more clearly visible.

Most people are familiar with Narrow leaf plantain, a common weed found in nearly every yard in suburban America. But few know that plantain has
Plantain inflorescences
flowers. The peculiar-looking thing at the end of the green stalk is an inflorescence (a collection of flowers). But, you ask, where are the petals? There are none. Plantain is wind pollinated and most such flowers have done away with petals -- they just get in the way of pollen reaching the female parts of the flower. The ring of white things you can see in the photo to the left are the anthers, the structures of the flower that produces pollen. The plantain inflorescence is made of hundreds of tiny flowers. Flowers mature first at the bottom of the inflorescence and are initially female -- just the style and stigma project out into the world, ready to receive pollen from a neighboring plant. Over a period of days a wave of flower opening slowly spreads upward, with each newly opened flower being female only. After a few days the functionally female flowers develop their anthers and the stigmas become unreceptive to pollen. That wave of functionally male flowers follows the wave of functionally female flowers upward toward the top of the inflorescence. The flowers below the circle of anther-bearing flowers are now making seeds if they were fertilized.

If you shake a plantain on a dry sunny morning you will see a cloud of white dust appear. This is composed of the pollen grains released by the anthers. The pollen of wind-pollinated flowers is dry and light so it can be easily carried by the wind. Insect pollinated flowers is usually heavy and sticky so that it can adhere to the body of the pollinator.
Anyone who has eaten at the many Hispanic restaurants in Athens probably noticed plantain on the menu. The adventurous may have ordered some out of curiosity and discovered that a plantain is a banana. One our student ramblers, Silvio, wondered how the same word came to be used for a common weed as well as a banana. I found an answer here, quoted below:

"banana," 1555, from Sp. plátano, plántano, probably from Carib platana "banana" (Arawak pratane), and altered by assoc. with Sp. plátano "plane tree," from M.L. plantanus "plane tree," itself altered (by association with L. planta "plant") from L. platanus (see plane (4)). So called from the shape of its leaves. There is no similarity or relation between this plant and plantain (2).
"weed of the genus Plantago," c.1265, from Anglo-Fr. plaunteyne, O.Fr. plantain, from L. plantaginem (nom. plantago), the common weed, from planta "sole of the foot" (see plant (n.)); so called from its flat leaves.

Poison Ivy fruits:
Poison Ivy developing fruit
Just behind the plantains is a tree with a very large poison ivy vine and number clusters of ripening fruits. When the fruits mature they will be avidly consumed by birds who will fly off with their tummies full. Sometime and distance later the bird will do what all birds do -- do-do -- and plant the poison ivy seed in its own clump of fertilizer. No wonder there is so much poison ivy around.

Other plants in the middle ROW:
We found several other plants blooming in this part of the ROW: Carolina Desert Chickory (Pyrrhopappus caroliniana),
Butterfly weed
Butterfly weed, Carolina Geranium and, by the fence next to the road, Indian Heliotrope (Turnsole).

Plants in the lower ROW
The lower part of the power line ROW, between the gate and the river is very moist. When the river floods it is under water for an extended period of time; frogs and toads breed in the pools that form in low lying areas during and after heavy rains. So it is not surprising to find plants like sedges and rushes growing in the
moister areas. (We discussed how to identify these plants in this Ramble Report.) Other plants are not yet blooming but are vigorously growing. Of these the most noticeable are several kinds of Wingstems (Verbesina spp.), Ironweed (Vernonia spp.) and Goldenrod (Solidago spp.). Box Elder is especially abundant here and we found Dock or Sheep Sorrel growing along the path.

Goldenrod ball gall:
A close look at the goldenrod reveals that many plants have a large, spherical swelling on the stem, just a few inches from the top of the plant. This swelling is a type of gall and is caused by a fly, Eurosta solidaginis (pronunciation: you-ROSta soul-uh-DODGE-eh-nis; no common name), but we can call it the goldenrod gall fly). The flies emerge from their galls in the spring, when the goldenrod is 3-4 feet tall. The female fly lays a single egg in the growing tip of the goldenrod. When the egg hatches the maggot eats its way down the stem and the plant responds to this by creating the large, spherical swelling. The maggot continues feeding on the tissue of the gall throughout the summer. During the fall the maggot chews its way toward the surface of the gall, making an escape tunnel. But the tunnel is not open, it is covered by
Cutting open a gall
a thin skin of plant tissue. The maggot then becomes quiescent and remains in suspended development during the winter, protected from freezing by anti-freeze compounds in its body fluids. As the weather warms the next spring the maggot resumes development and pupates. The adult fly emerges from the pupa, crawls up the escape tunnel and inflates a "balloon" on the front of its head. The hydraulic pressure of the balloon pressing against the covering of the tunnel pops it open and the fly is free to emerge, mate and repeat the process.

I cut open a gall but could not find the maggot. It may have died shortly after the gall formed.

Some birds, especially Downy Woodpeckers have discovered that if they peck open the galls in the winter they will be rewarded with a nice meal. Next November we should remember to check these galls to see how many have been discovered by birds.

At the river we turned left on the White trail and walked through the Privet jungle to the Orange Trail Spur. In addition to Privet there is poison ivy and box elder growing on either side of the path. Emily demonstrated how to tell the difference between these two plants. The most reliable difference is that box elder has opposite leaves while poison ivy has alternate leaves.

At the junction with the Orange Spur trail there is a large tree with three different vines growing up it: a Crossvine, and two Greenbriers, Common greenbrier and another unidentified but different form.

Up on the Orange Spur trail Don found a White Avens in bloom. This is a plant we don't see blooming very often, so we need to keep our eyes open for it in future walks.

Then it was off to Donderos' for our usual conversation and beverages.
Common Name
Scientific Name
Trillium sp.
Witch hazel
Hamamelis virginiana
American Beech
Fagus grandifolia
Tradescantia sp..
Thimble Weed
Anemone virginiana
Post Oak
Quercus stellata
Fraxinus sp.
Rhus glabra
Cercis canadensis
Hop Hornmbeam
Cat's Ear
Ostrya virginiana
Hypocharis radicata
Daisy Fleabane
Erigeron sp.
Field Madder
Sherardia arvensis
Carolina Geranium
Geranium carolinianum
Narrow Leaf Plantain
Plantago lanceolata
Poison Ivy
Toxicodendron radicans
Butterfly Weed
Asclepias tuberosa
Carolina Desert Chickory
Pyrrhopappus carolinianus
Indian Heliotrope
Heliotropium indicus
Carex sp.
Juncus sp.

Solidago sp.
Box Elder
Acer negundo
Bignonia capreolata
Common greenbrier
Smilax rotundifolia,
Smilax sp.

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