Friday, November 15, 2013

November 14 2013 Ramble Report

This week's report is written by Don Hunter with a few additions by Dale. The photos are sample from a larger number that can be seen on Don's facebook album.

Here's the link to the "What a Plant Knows" Coursera class . You can register for it for free. It has already finished but the video lectures will be available until Nov. 26. If you register for the class you will be able to watch all the videos and read the discussion forums. (You can also take the quizzes, but they will not be "counted." Daniel Chamovits is the lecturer as well as the author of the book What a Plant Knows and I found him to be a good video lecturer.

 “It was a cold and frosty morn…..”

Kitty reading Emerson
This morning it was 21 degrees at daybreak in the Athens area and despite the frigid temps, we had twenty-one Ramblers show up for this, the next to the last official Ramble for the 2013 season.  Everyone was bundled up as they arrived at the arbor and, after a few bits of information passed along by Hugh and Dale, we had a nice reading provided by Kittie Everett, who read an excerpt from Ralph Waldo Emerson’s essay Nature:

The tempered light of the woods is like a perpetual morning, and is stimulating and heroic. The anciently reported spells of these places creep on us. The stems of pines, hemlocks, and oaks, almost gleam like iron on the excited eye. The incommunicable trees begin to persuade us to live with them, and quit our life of solemn trifles. Here no history, or church, or state, is interpolated on the divine sky and the immortal year. How easily we might walk onward into the opening landscape, absorbed by new pictures, and by thoughts fast succeeding each other, until by degrees the recollection of home was crowded out of the mind, all memory obliterated by the tyranny of the present, and we were led in triumph by nature.

Following the reading, we headed down the paved path to the Dunson Native Flora Garden, up the White Trail to the power line right-of-way and into the forest, where we hooked up with the Blue Trail and walked it past the first Torreya clearing, on to the second Torreya clearing and returned by the same route.

frozen Witch Hazel flowers
At the first stop, Dale showed us a blooming Witch Hazel (Hamamelis virginiana). The petals were still frozen and crumpled, but when we passed by them two hours later they had recovered nicely. The witch-hazels are deciduous shrubs or (rarely) small trees.  They are popular ornamental plants, grown for their clusters of rich yellow to orange-red flowers which begin to expand in the autumn as or slightly before the leaves fall, and continue blooming throughout the winter (Wikipedia).   There were numerous, bright yellow flowers adorning the example we saw.  Earlier in the week, the flowers were being heavily visited by flies that looked like small yellow jackets, no doubt going about the business of pollination.  Winter moths, which come out in November and December and can be seen around porch lights at night, could be nocturnal pollinators of these fall and winter blooming shrubs.  If pollinated, these flowers will wait until spring to develop their ovaries and seeds.

Silver Plume grass
Right before we arrived at the power line right-of-way, we stopped to look and several grasses.  Little Bluestem (Schizachyrium scoparium), characterized by its alternating blue
Splitbeard Bluestem
or purple and green markings on the stem was our first stop here.  As we move further into winter, the colored markings will turn brown.  Nearby we also saw River Oats (Chasmanthium latifolium) , Splitbeard Bluestem (Andropogon ternarius) and Silver Plume (Saccharum alopecuroides) grasses.  The Split Beard Bluestem is aptly named by the twin tufts of remnant flowers at the ends of the grass stalks.  The Silver Plume grass is a towering giant, one of the tallest, if not the tallest, of the grasses seen along the Bot Garden trails.  We saw the occasional panic grass (Panicum sp.) and the Dog Fennel (Eupatorium capillifolium) here was also striking this morning, with its coating of frost and small ice crystals.

Redbud bud galls (closeup)

Numerous bud galls visible against the sky
Next, we saw a Redbud tree (Cercis canadensis) infested with a large number of bud galls on its limbs and twigs.  These galls are the result of tiny mites laying their eggs in the terminal and lateral buds of the branches.  When the eggs hatch, the larvae eat the gall tissue.  At this time of year, the mites are no longer present, just the remaining gall.  Just how are the galls formed?  Either mechanical damage or salivary secretions introduced by the mites initiate increased production of normal plant growth hormones.  These plant hormones cause localized plant growth that can result in increases in cell size (hypertrophy) and/or cell number (hyperplasia). The outcome is an abnormal plant structure, the gall (Wikipedia).   Dale has been observing this particular Redbud for 18 years.

Frost flowers at base of Verbesina virginica
Moving on up the right-of-way, we were treated with what was the first of many examples of “frost flowers”, probably the highlight of the ramble.  What initially appeared to be a white plastic bag draped around the base of a plant was actually ice that had been extruded from the stem. Several web sites have excellent descriptions of this phenomenon: the Texas Parks and Wildlife Department as well as this website. A nice video, including some time-lapse shots of frost flowers forming on Verbesina virginica can be found here.

In the same locations as the frost flowers, we saw an abundance of dried Bee Balm (Monarda sp.) seedheads, covered with frost and ice crystals.

We walked back down the power line and turned into the forest on the White Trail and made our way to the Blue Trail and immediately came upon one dead trees, a large
Wood-rotting fungi on Northern Red Oak
Northern Red Oak (Quercus rubra), the upper trunk lying on the ground and the lower still standing, even though it is dead.  Wood rotting fungi were abundant on both trunks. 
There are two general kinds of wood rotting fungi, named for the color of the wood remaining after they have digested what they can: white rots and brown rots. Woody tissue is made of plant cells. All plant cells are surrounded by a cell wall made largely of cellulose (that's what paper is made from). But cellulose alone is not very strong and in woody plants it is strengthened by the addition of a substance called lignin. The combination of cellulose and lignin enables trees to grow to tremendous heights and not be crushed by their own weight. Cellulose is light colored and lignin is dark. The fungi that rot wood digest either cellulose or lignin. Those that attack the cellulose leave behind the dark colored lignin and are called "brown rots." Those that digest lignin leave behind the light colored cellulose and are called "white rots." (There are some fungi that can digest both cellulose and lignin.) The only way to tell whether a particular fungus is a white or brown rot is by looking it up in a book or examining the color of the wood remaining after it has done its job.

Small Torreya behind Hugh
Shortly, we passed by the first of two Torreya propagation sites adjacent to the Blue trail and walked off-trail to take a closer look at one of the Florida Torreyas (Torreya taxifolia).  This tree is also known as Gopher Wood, Stinking Yew, or Stinking Cedar and is a rare and endangered species found in northern Florida and southwest Georgia. The State Botanical Garden is participating in a program to preserve this plant in the southeast U.S.

Continuing back on the Blue trail, we came upon a couple of small Water Oaks (Quercus nigra), where Dale pointed out the leaves on several of the trees.  On a small sapling all the leaves were unlobed and resembled the leaves of a Willow Oak. This seems to be a common characteristic of young Water Oaks here in the Garden. On larger saplings some of the leaves are developing shallow lobes that are more typical of a Water Oak. 
We also saw two distinctly different leaves from the Northern Red Oak, one from the shaded area of the tree, which was very broad, with a lot of surface area to maximize it’s exposure to available sunlight, the other from higher in the tree, which looked more typical of Northern Red Oaks, being less broad, with deeper sinuses separating the sharp tipped lobes.

A little further down the Blue Trail, Hugh pointed out that this area was a very good
Red Maple leaves (note red petioles)
example of an early succession forest, with many large pines, both Loblolly (Pinus taeda) and Shortleaf (Pinus echinata)  and Black Cherry (Prunus serotina).  There are hardwood saplings present but they are far from mature.  Hardwoods in this succession forest are represented by maples and oaks (Water Oaks and Northern Red Oaks), as well as American Beech (Fagus grandifolia).  We saw a small Red Maple (Acer rubrum), easily identified by its toothed leaf lobes and red petioles (leaf stems). 

Next we stopped at a small American
Beech leaf
Beech tree, with its colorful thin, papery leaves, with wavy leaf margins (remember, “beaches”  have waves, when trying to identify this tree).  Beech trees hold their leaves throughout the winter and shed them in spring, right before the new leaves emerge from the long and sharp pointed buds, which were pointed out by Dale at this stop.
Several trees retain their leaves throughout winter: Beech, Hop Hornbeam, Chalk Maple and several of the Oaks. In addition to the beech trees,  chalk maple, hop hornbeam and some of the oaks hold on to their leaves throughout much or most of the winter. This retention of dead leaves is called marscence, a term that is useful in impressing botanical nerds. Botanists know what causes leaves to fall in the autumn, but they don't know why some trees retain the dead leaves until spring. Some have suggested that when leaves are dropped in the fall any residual nutrients they contain might be leached away when the roots are cold and cannot effectively absorb them. By holding on to their leaves marscescent trees can recover those nutrients when they become more physiologically active in the spring. But this is not a very convincing argument and there is little data to test it.

Here we saw one of the few examples of trail fauna we were to see today.  A Daddy (or Grandaddy) Longlegs, also known as a harvestman (Phylum Arthropoda, Class Arachnida, Order Opiliones) was seen working its way around a large Loblolly Pine tree.  Dale allayed any fears harbored by Ramblers with regard to toxicity or of these arachnids.  An urban legend claims that the harvestman is the most venomous animal in the world, but the harvestman possesses fangs too short and a mouth too round and small to bite a human and therefore is not dangerous (the same myth applies to a similar looking spider, Pholcus phalangioides, and the cranefly, which are both sometimes called a 'daddy longlegs').    Furthermore, none of the known species of harvestmen have venom glands; their chelicerae are not hollowed fangs but grasping claws that are typically very small and definitely not strong enough to break human skin. Even though most people would consider Harvestman spiders, these are not real spiders, but bear a great resemblance to spiders given they also have eight, sometimes very long, legs.  (Wikipedia)

After popping out into the northwestern most of the two Florida Torreya clearings, near
End view of Winged Sumac showing spiral leaf arrangement

Winged Sumac showing alternate leaf arrangement
the northern end of the Blue Trail, we saw more Florida Torreya, as well as scarlet colored Winged Sumac (Rhus copallina) and some dying and brown White Crownbeard.  Dale pointed out that the leaves of the sumac are alternate, with one leaf stem being 137.5 degrees around from the one above or below it, less than the 180 degrees you might assume.  This slightly staggered spiraling alignment allows each leaf to get its share of sunlight, not being totally shaded out by the leaf above it.  We also saw many more examples of frost flowers in this clearing, most of which were associated with the White Crownbeard.

At Donderos'
At this point, we turned around and retraced our steps back to the Visitor Center where a large group gathered at Donderos for refreshments and great conversation.


Witch Hazel (Hamamelis virginiana)
Little Bluestem (Schizachyrium scoparium)
River Oats (Chasmanthium latifolium)
Splitbeard Bluestem (Andropogon ternarius)
Silver Plume (Saccharum alopecuroides)
Panic grass (Panicum sp.)
Dog Fennel (Eupatorium capillifolium)
Redbud tree (Cercis canadensis)
Frostweed or White Crownbeard (Verbesinia virginica)
Bee Balm (Monarda sp.)
Northern Red Oak (Quercus rubra)
Turkey Tail mushrooms  (Trametes versicolor)
Florida Torreya (Torreya taxifolia)
Water Oak (Quercus nigra)
Loblolly Pine (Pinus taeda)
Shortleaf Pine (Pinus echinata)
Black Cherry (Prunus serotina)
American Beech (Fagus grandifolia)
Winged Sumac (Rhus copallina)

Harvestman or Daddy Longlegs (Order Opiliones)

No comments:

Post a Comment

Post a comment