Sunday, August 23, 2015

Ramble Report August 20 2015



Today's report was written by Dale Hoyt. The photos that appear in this blog are taken by Don Hunter; you can see all the photos Don took of today's Ramble here.

Sixteen ramblers met at the Arbor at 8:00AM on a beautiful, cool morning just right for a ramble.

Today's reading: Dale read an excerpt from Joseph Wood Krutch's essay, Man's Ancient, Powerful Link to Nature:

On some summer vacation or some country weekend we realize that what we are experiencing is more than merely a relief from the pressures of city life; that we have not merely escaped from something but also into something; that we have joined the greatest of all communities, which is not that of men alone but of everything that shares with us the great adventure of being alive.

Announcements:
1.       Next week's ramble will be the last of the year to start at 8:00AM. Beginning in September all our rambles will start at 8:30AM.
2.       Sandy Creek Nature Center will resume their monthly guided trail walks in September. The walks begin at 9:00AM on the first Wednesday of the month; meet at the Visitor Center. The first walk will be on September 2 and will be led by Sandy Creek's expert naturalist Carmen Champaign.
3.       The University is celebrating the 250th anniversary of John and William Bartram's Natural History Expedition in Colonial Georgia. Over the next month and a half there will be a variety of presentations about the Bartrams. Visit this website for more information about the planned events.

At the Arbor: Before starting the ramble we discussed last week's discovery of a dead Green Ash tree on the Orange trail. We were fearful that the tree had been killed by the Emerald Ash Borer (EAB), an insect that is decimating ash trees in the North and rapidly spreading across the country. Last Monday several experts examined the tree and found no evidence of the EAB. The tree was killed by an infestation of bark beetles. We can breathe a sigh of relief, for a while anyway. The EAB is already in Georgia (since 2013) and it is only a matter of time before it arrives in Clarke Co. Visit this website for up-to-date information about the EAB in Georgia.

Eleanor brought an interesting find from her house – a small scorpion. We only have a single scorpion species in this part of the state: Vaejovis carolinianus AKA Southern Unstriped Scorpion, a terribly awkward name. This species is small and uniformly dark in color. It is typically found outdoors, under bark or rocks, and only occasionally found in houses. Over the last thirty years we can only remember finding one in our house. These scorpions have a painful sting, like a wasp, but the discomfort lasts less than an hour. The main problem from a sting arises if you are hypersensitive to the venom. In that case medical attention is needed.

Today's route: From the arbor we strolled down the cement walkway through the Shade garden to the Dunson Native Flora garden. There we wandered the paths and at the bottom of the Dunson garden we exited and walked up the road to the White trail. Turning left on the White trail we proceeded to the power line right of way and walked a short distance uphill before turning around and returning to the arbor.

Shade Garden: One of our new ramblers, Marianne, recently moved here from the Northeast and wanted to know how to identify Ash trees, so we stopped in the shade garden to point out a small White Ash. The two commonest Ash species found in Georgia are the Green Ash and White Ash; Green being the most common in this area. (White Ash is more abundant in the mountains.) Both Ashes have compound, opposite leaves; those of Green Ash usually have 5 leaflets while White Ash typically has 7 leaflets. The bark ridges of Ash form skinny diamond shaped patterns on the trunk, but this characteristic is also found on some of the local hickory species. (But the hickories have alternate, compound leaves.) In fact, we found a tree near the labeled White Ash that had that typical diamond-mesh bark and compound leaves. But there was some disagreement about whether it was an ash or a hickory. Some of us saw clearly opposite leaves, but others pointed out that the leaflets looked more like those of a hickory. We left with no clear decision.

Dunson garden: Our focus today was on ferns, but we didn't neglect other things we saw. I'm going to organize this section around these topics: ferns, other plants and caterpillars.
Ferns: I prepared a Fern minibook to help identify seven ferns commonly seen on the Orange and other trails as well as the Dunson garden. Click here to get the booklet; you can download and print it from Microsoft Word. 

A good book to help you identify ferns is: Field Guide to the Ferns and Other Pteridophytes of Georgia by Lloyd H. Snyder Jr. and James G. Bruce, University of Georgia Press. Some of the scientific names are out of date, but the common names are still good.

Terms that refer to fern parts (and other stuff): Here are some descriptive terms that name parts of a typical fern or portions of the fern life cycle:
·         Frond: The entire stem and leafy part of a fern is called a frond. A fern plant may be made up of one or more fronds. Example: Ebony spleenwort is frequently just a single frond. A Christmas fern is generally composed of many fronds.
·         Blade: The leafy part of the frond.
·         Stipe: The "stem" of the fern. The stipe is the leafless portion of the frond stem from the ground to the first leafy structure.
·         Rachis: The part of the frond stem that bears leafy structures. Example: in Lady fern the rachis is frequently red; in Ebony spleenwort it is black.
·         Pinna (pl., pinnae): The "leaves" of the frond.
·         Pinnule: Sometimes the pinnae are subdivided into smaller leaflets. Each leaflet is called a pinnule (meaning: little pinna).
·         Sorus (pl., sori): Small brown patches often found on the underside of a frond. Each sorus is a group of much smaller structures, called sporangia (sing., sporangium).
·         Sporangium (pl., sporangia): Each sporangium produces numerous microscopic spores.
·         Sporophyte: A plant that produces spores.
·         Spore: A type of reproductive cell produced by a sporophyte. Spores in ferns are produced by a special kind of cell division called meiosis.
·         Meiosis: A kind of cell division that produces spores in ferns or gametes (sex cells, eggs or sperm) in animals. Fern spores and animal gametes carry only one set of chromosomes The cells that produce the fern spores or animal gametes have two sets of chromosomes.
·         Mitosis: A kind of cell division that produces daughter cells that have all the chromosome sets of their parent cell.
·         Fertile frond: A frond that bears sori.
·         Sterile frond: A frond that lacks any sori. Some ferns have different appearing fertile and sterile fronds. In such plants the fertile fronds may only develop at certain times of the year. Example: The Sensitive fern we saw today has a separate fertile frond that looks very different from the sterile fronds. Christmas fern has a mixture of fertile and sterile fronds, but the fertile fronds also bear sterile pinnae.
·         Gametophyte: A plant that produces sex cells (gametes; either male or female). In ferns when a spore germinates it develops into a gametophyte. The fern gametophyte is very small and hardly ever seen because it is so inconspicuous.
·         Zygote: A fertilized egg. The zygote has two sets of chromosomes, one set from the sperm cell and one set carried in the unfertilized egg. The zygote develops into a multicellular embryo by dividing many times. Each of the cells in the embryo contain two sets of chromosomes because the zygote divides by mitosis.

Ferns we saw: Sensitive fern, Royal fern, Christmas fern, Ebony spleenwort, Southern maidenhair fern, Northern maidenhair fern, Broad beech fern, New York fern, Cinnamon fern and Marginal wood fern.
Southern Maidenhair fern

Northern maidenhair fern
Royal fern
Ebony spleenwort
Marginal wood fern
New York fern

The distribution of sori on the frond is an aid to identifying ferns. Each kind of fern usually has a characteristic location and pattern where the sori are found. Some examples:

Christmas fern: The sori are found on the underside of the pinnae toward the end of the frond. Not every frond develops sori, but, in those that do, the pinnae that bear the sori are distinctly smaller than the sterile pinnae.
Christmas fern; fertile pinnae at end of frond

Sensitive fern: The sori develop on a fertile frond that is separate and completely different looking than the sterile frond.
Sensitive fern fertile frond (center)
surrounded by sterile fronds



Marginal wood fern: The sori develop next to the edges (the margin) of the pinnae.
Marginal wood fern
Sori located near edge of pinnae

Fern reproduction: Ferns can reproduce vegetatively, by sprouting new fronds or sending out rhizomes that produce more fronds some distance from the parent plant. In these cases all the fronds are genetically identical clones. Ferns can also reproduce sexually by producing spores. 

Spores vs. seeds: There is a tendency to think of spores as seeds since both are important in propagation of their parent plants. But spores are very different from seeds. 

Firstly, fern spores are usually single cells and have little or no nutritive material to support their growth. When a spore germinates it is on its own; it must be able to make enough food via photosynthesis to support its future growth. 

In contrast, a seed contains a multicellular embryonic plant plus a supply of food to support the developing embryo. When you eat cereal grain products you are actually consuming the seed's nutrient store, mostly starches and oils, intended for the embryonic plant. In fact, during food processing, the embryo is discarded to make wheat flour, white rice and grits, so, unless you eat whole grain wheat or brown rice, you're missing out on the nutrients found only in the embryonic plant. 

Another difference is the type of plant that is produced by a fern spore and a seed. When the fern spore germinates and grows it does not develop into a sporophyte. It becomes a small, green plant about the size of your little fingernail. This plant is known as a gametophyte because it will produce egg and/or sperm cells. (The general term for sex cells, egg or sperm, is gamete, hence, this plant is a gametophyte – a gamete producing plant.) Once the sperm cell finds an egg cell and fertilizes it the resulting zygote now has two sets of chromosomes. The embryo develops, through the cell divisions of the zygote, into a sporophyte. The developing sporophyte is initially dependent on the gametophyte for its nutritional support.

What kind of plant is produced by a seed? It has two full sets of chromosomes in each cell so it must be a sporophyte. So what are the spores that are produced by a seed plant sporophyte? They are familiar to you as the pollen and the ovules. Because they are different in size botanists call them microspores and megaspores, respectively. 

Other plants: Only a few flowers were blooming today and they were looking a little ragged after being beaten by the heavy rains of the last several days. The Catch fly we saw last week was still in flower, as were the skullcaps and the elephant's foot. We also found the bright red berries of Jack-in-the-pulpit. 

Critters: We found three caterpillars and one spider today. Of the caterpillars the most
Spun glass slug moth caterpillar
bizarre was a Spun glass slug caterpillar. This caterpillar is a member of the moth family Limacodidae, the Slug moths. They are named for the way in which their caterpillars move. Most caterpillars have fleshy legs on their abdomen that they use for creeping across leaves and twigs. The slug moths have instead a sucker on the belly and they use it to glide along, something like a slug, hence, the common name. Many caterpillars in this family have stinging hairs on the body. If you contact them with your skin you will feel a burning sensation similar to that produced by stinging nettles. The spun glass slug that Catherine found is young; as it grows the fine, glass-like projections will increase in number and grow longer.

The spider, a triangulate orb weaver was spotted by Don and is small this early in the
Triangulate orbweaver
season. (They were even smaller in the spring.) Most of our orb weaving spiders are annual species – they only live one year. Typically the female lays eggs in the fall and then dies. The eggs overwinter and hatch in the spring. The early part of the year the baby spiders are so small that they are seldom seen, but as they feed they grow larger and finally become noticeable when they reach a size that can produce a web we run into when we walk the trails..

White trail: After leaving the Dunson garden we walked up the road to the White trail and checked on the American beech tree we have been watching all summer. The beechnuts are turning a darker shade of brown and Don sampled one, reporting that it was pretty astringent, but not as bad as an unripe persimmon.

The trail passes by what used to be the flower garden and we still find some of those plants
Lycoris sp. flower
hanging on. Today we found a number of Lycoris still bearing rain-beaten flowers. These plants have many different names: Surprise lily, Hurricane lilly, Rain lilly. About this time of year they send up a flowering stalk with no leaves. The sudden appearance of the blooming stalk led to the "Surprise" name. The Hurricane and Rain common names probably refer to the time of year and weather conditions that seem to prevail when the flowers pop out of the ground.

The Hophornbeam further along the trail has a huge number of papery fruits, each with a small seed at the base. We've also been watching the progress of this tree and the seeds are ripe and ready to drop off the tree.
Ripe fruits of Hophornbeam

Each papery fruit holds a single seed


Purpletop/Greasy grass
Powerline: The power line continues to put on a display of flowers and grasses. The most prominent flowers today were
Beaked panic grass
the Mountain mints and Late flowering thoroughwort. The Purpletop (or Greasy grass) was especially noticeable and there was an abundance of what I initially thought was a sedge. (My moment of embarrassment!) I twiddled the stems and felt edges. Following the old mnemonic, "Sedges have edges," I jumped to the wrong conclusion. The stems were not triangular. Emily snapped a photo with her cell phone and sent it to Linda Chafin who identified it as Beaked panic grass. It is spectacularly abundant this year! Other flowers that we noticed amidst all the grass were Field thistle and a few Carolina desert chicory.

Then it was time to return and the usual crew gathered at Donderos' for snacks and beverages.

Dale Hoyt

SUMMARY OF OBSERVED SPECIES:
Lady Fern
Athyrium filix-femina
White ash
Fraxinus americana
Christmas fern
Polystichum acrostichoides
Sensitive fern
Onoclea sensibilis
Northern red oak
Quercus rubra
Black snake root
Sanicula sp.
Royal fern
Osmunda regalis
Ebony spleenwort
Asplenium platyneuron
Triangulate orb weaver
Verrucosa arenata
Thick leaf/ovate leaf catchfly
Silene ovata
Northern  horse balm
Collinsonia canadensis
Southern maiden hair fern
Adiantum capillus-veneris
Asiatic day flower
Commelina communis
Hairy skullcap
Scutellaria elliptica
Elephants foot
Elephantopus tomentosa
“Pancake” mushroom
Not identified
Northern maidenhair fern
Adiantum pedatum
Broad beech fern
Phegopteris hexagonoptera
Cinnamon fern (?)
Osmundastrum cinnamomeum
New York fern
Thelypteris noveboracensis
Slug moth capterpillar
Family Limacodidae
Marginal wood fern
Dryopteris marginalis
Jack in the pulpit (berries)
Arisaema triphyllum
Banded tussock moth caterpillar
Halysidota tessellaris
American beech tree
Fagus grandifolia
Surprise lily
Lycoris sp.
Hophornbeam
Ostraya virginiana
Marasmius mushroom
Marasmiellus sp.
Late flowering thoroughwort
Eupatorium serotinum
Purpletop/Greasy grass
Tridens flavus
Beaked panic grass
Panicum anceps
Mountain mint
Pycnanthemum incanum
Field thistle
Cirsium discolor
Carolina desert chicory
Pyrrhopappus carolinianus
Butterfly pea
Clitoria ternatea
Garden snail (tentative)
Cornu aspersum
Orange striped oakworm


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