Tuesday, December 25, 2018

Christmas with phytoplasma

Merry Christmas everyone!

I came across a recent blog post with a Christmas theme that I wanted to share with you. It's about Poinsettias -- how they are propagated and how they came to look the way they do. Read it and you'll see how their appearance is caused by an infectious agent called a phytoplasma and, along the way, you'll find a lot of interesting information about the plant propagation industry.

Also, we encountered a phytoplasma earlier this year on our July 19th Nature Ramble. It even has a name: Aster Yellows. Take a look at the Ramble Report to see how the disease affects Purple Coneflowers. 

While I have your attention I wanted to remind you that the Garden is closed this week, so we've decided to hold our informal social hour at Sandy Creek Nature Center this Thursday, Dec. 27, 2018, at 10 a.m. Coffee will be free and you can bring some snacks to share, but don't feel that you have to. If the weather permits, we'll take a stroll on one or two of the trails at the Nature Center after coffee.

Have a happy New Year!

Dale 

Gingerbread Peeps before (below) and after (above) 15 seconds in a microwave oven.
Happy Holidays!

Friday, November 16, 2018

Ramble Report November 15 2018


Today's Ramble was led by Linda Chafin.
Here'sthe 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 Linda Chafin.
Ramble Report November 15, 2018
Today’s leader: Linda
Today's emphasis:  Seeking what we find and getting back by 10.
7 Ramblers today.
Today’s Reading: Jeff read “Tapestry,” by Phyllis Barnet, a commemoration on a plaque at the Bryant Ridge Appalachian Trail Shelter in Virginia.

Autumn threads it slow burn
through the forest loom
we spin into winter and my
twenty forth year
the 1st without you brother,
your last fall fringed in loose hung stings
I braid them now, twist to
yarn the quiet fire that brought
you back to dust
This shuttle beats the rhythm of
your heart, I'll lay the half-done
cloth for the wind to weave over
mountains season after season
after season

Show and Tell: Dale brought White Oak acorns gathered two weeks ago to see how many were occupied by weevil larvae. Over the course of two weeks six weevil larvae chewed their way out of their host acorn. One large acorn had germinated even though it had 4 exit holes, indicating that 4 weevil larvae had been eating its food stores. All told, six weevil grubs emerged from 15 acorns.

Today's Route:   We walked through the Great Room and out back through the International Garden, took the Purple Trail to the river and returned to the Visitor Center in time to meet the other ramblers for refreshments and conversation at the Cafe Botanica.

LIST OF OBSERVATIONS:

Plaza Fountain:

Dorotha asked about all the fresh new pitchers on the pitcher plants in the plaza fountain. Most of these pitcher plants are hybrids between the White-topped Pitcher plant and another species of pitcher plants, as can be seen by the white mottling and ruffled edges at the top of many of the pitchers. White-tops are famous for their twice-yearly pitcher flushes – one in spring, the other in fall, with the latter being especially vigorous. The plants in the fountain seem to have inherited the fall-flushing gene from their White-top ancestor.

Herb and Physic Garden:

American Witch Hazel; even without the rain drops the petals are scraggly.
Witch Hazel is currently blooming, one of only two native flowering plants that bloom at this time of year. Actually they started blooming several weeks ago, in late October. Whenever autumn days are warm and sunny enough for insects to fly you can find them on the Witch Hazel flowers. Further north, with a cooler climate, naturalist Bernd Heinrich suggest that a group of moths, called, appropriately, Winter Moths, might be their pollinators. Winter moths can fly when the air temperature is close to freezing.
And what, you ask, is other native flowering plant that blooms as late or even later than Witch Hazel? Mistletoe!

Ginkgo leaves in their fall color.
Linda pointed out the golden colors of the Ginkgo tree and the Pawpaw patch. Dale reminded us that the yellow color in autumn leaves is due to the presence of a group of pigments called carotenoids. These pigments are present in the leaf throughout the growing season, but are masked by chlorophyll. When the chlorophyll degrades in the fall (a process triggered by longer, cooler nights), the yellow color shines through. Yellowing of leaves any time of the year due to disease or herbivory results from the same process: the breakdown of chlorophyll.
Many people notice the brilliance of the yellow Ginkgo leaves. This startling color is not solely due to carotenoids. An additional chemical, 6-Hydroxykynurenic acid (6-HKA), is present in the leaves and reaches its highest concentration just before they fall. 6-KHA has an unusual property that explains why the yellow color of the leaf is so intense: it absorbs ultraviolet light, which is invisible to the human eye, and re-radiates it in the yellow part of the visible light spectrum. This phenomenon is known as flourescence. The same principle is used by fabric whiteners but the whiteners re-radiate a broader spectrum of light, which we perceive as white.

The red color in fall leaves has a different origin. As nights lengthen and cool, a waxy layer forms at the base of the leaf stalk of trees such as maples, sourwood, sweet gum, and black gum, sealing the leaf off from the plant’s vascular system. Sugars that are produced in the leaf on warm autumn days are trapped in the leaf by the waxy layer and are converted to a group of pigments called anthocyanins. Anthocyanins include the pigments responsible for nearly all red and purple coloration in plants, including red and pink flower petals; the outer surface of apples, cranberries, and blueberries; and the lower surface of Crane-fly Orchid leaves, just to name a few. (An exception are beets, colored by a non-anthocyanin pigment called betalain.)

One reason that southern autumns are usually not as colorful as those in the northeast is that our forests are dominated by hickories and some oak species whose leaves do not produce anthocyanins. Northern forests are more likely to include sugar maples, whose leaves do. Also, we in the Piedmont rarely get that lucky combination of warm days and cold nights that produce the brightest colors– a good excuse for a trip to the Blue Ridge!

Purple Trail:

Water Oak acorn; from the bottom.

Partially eaten Water Oak acorn; from the top.
Numerous Water Oak acorns were seen scattered along the leaf-covered path on the Purple Trail. Many were half-eaten, probably by squirrels or chipmunks, and were highly visible due to the orange color of the exposed meat of the acorn. That coloration might be due to the presence of tannins. Water Oaks are members of the red oak subgroup and have higher tannin concentrations than white oaks. Tannins are astringent and, in high concentration, make food almost inedible. Unripe persimmons are an example you may be familiar with. Red wines also get their “bite” from tannins in the grape skins. (White wines, which lack the bite, are made from grapes minus their skins.) But tannins have another effect: they inhibit the growth of fungi that would like nothing better than to feed on acorns and other fruits. The partially eaten acorns might result from naïve rodents discovering what is edible and what is not.

Hornbeam Disk mushrooms
There is a bumper crop of Hornbeam Disk mushrooms on the Hophornbeam trees this fall.  Despite recent heavy rains, the disks appeared to have desiccated a bit, becoming more like shallow, white-rimmed cups.

Sweet Gum leaves, one a deeply lobed sun leaf and the other a less lobed, more typical star-shaped leaf from lower down on the tree, where increased leaf surface maximizes photosynthesis in the filtered light.

A wet and shiny False Turkey Tail mushroom, with green stripes of algae growth alternating with unaffected red stripes.

A large, wet and shiny red-orange wood ear mushroom was seen on one of Northern Red Oaks we visited last week.

Coral-pink Merulius fungi growing on the downed Northern Red Oaks that we saw last week.  As usual, they seemed to be growing with False Turkey Tails.



Brilliant white examples of Little Nest Polypore


Lion's Mane
Don spotted two small Lion's Mane fungi on the underside of a fallen log. Lion’s Mane is widely collected as a choice edible mushroom. Our examples are still very small–Lion’s Mane can reach more than a foot in width.

SUMMARY OF OBSERVED SPECIES:

Ginkgo
Ginkgo biloba
Witch Hazel
Hamamelis virginiana
Pawpaw
Asimina triloba
Water Oak
Quercus nigra
Hop Hornbeam
Ostrya virginiana
Hornbeam Disk Mushroom
Aleurodiscus oakseii
Winged Elm
Ulmus alata
Sweet Gum
Liquidambar styraciflua
Northern Red Oak
Quercus rubra
False Turkey Tail
Stereum ostrea
Wood Ear
Auricularia sp.
Coral-pink Merulius
Phlebia incarnata
Little Nest Polypore
Trametes conchifer syn. Poronidulus conchifer
Lion's Mane
Hericium sp.


Sunday, November 11, 2018

Ramble Report November 8 2018



Today's Ramble was led by Dale Hoyt.
Here's the link to Don's Facebook album for today's Ramble. (All the photos in this post, unless otherwise stated, are compliments of Don.)
Today's post was written by Dale Hoyt.
Today’s Focus: Seeking what we find on the Purple Trail and the Orange Trail.
25 Ramblers met today.
Announcements & Reminders:
·        Next Thursday’s Ramble (Nov. 15) will be the last formal Nature Ramble of the year; formal Rambles will resume on March 7, 2019.

·        The first meeting of the NR book group will be next Thursday, Nov. 15 at 11:30 a.m. in the adult classroom. The book for discussion is “American Wolf.” Discussion moderator is Emily Carr.
·        Athens Christmas bird count is December 15th.  There will be ten teams in the Athens area, including one at the Bot Garden.
·        This invitation from Kathy Stege: “I would love Ramblers and guests to meet me at Heritage Park the day after Thanksgiving November 23rd at 9:00 for a hike. It's on the right just a few miles past Bishop on 441. Just show up. Dogs are welcome. 478-955-3422. Kathy.”

Today's reading:
Eugenia read a post-election poem by Ryan Warren, written in the tradition of an Irish blessing.
Dale read the November 1 entry from Donald Culross Peattie’s An Almanac for Moderns:
WHAT I love best in autumn is the way that Nature takes her curtain, as the stage folk say. The banners of the marshes furl, droop and fall. The leaves descend in golden glory. The ripe seeds drop and the fruit is cast aside. And so, with slow chords in imperceptible fine modulations the great music draws to its close, and when the silence comes you can scarce distinguish it from the last far-off strains of the woodwinds and the horns.

Show & Tell:
1.    
Germinated White Oak acorn; the white structure is the new root.
Dale brought a germinated White Oak acorn. The acorn was “planted” (placed on the surface of potting soil in a tall milk shake cup two-three weeks ago. The soil was kept moist. The acorn germinated after one week. The only visible sign was the appearance of the root from the pointed end of the acorn. In the next two weeks the root grew to a length of three inches. Acorns in the White oak group germinate soon after falling in the year they started growth. Those in the Red oak group take two years to develop and germinate the following spring.
Carla's mystery milkweed
2.     Carla brought a cutting from a milkweed plant she had purchased earlier this year. Like most of us, she had forgotten where it came from and what it was. It had a single pink and white flower and long, narrow leaves. None of us could determine what kind of milkweed it was.

Today's route: We went through the Visitor’s Center and out the back door, turned right through the garden to the head of the Purple Trail. We walked to the river on the Purple Trail, turned left on the Orange Trail and followed it to the bridge to the Flower Garden. We took the spur trail over the bridge and returned to the Visitor’s Center.

OBSERVATIONS:
Northern Red Oak acorn
Northern Red Oak. This is the time of year when the oaks are dropping their acorns. At the head of the Purple Trail there is a Northern Red Oak that is producing a lot of them. We found them scattered over the leaf litter in abundance. The shape of the NRO acorn is rotund; the books describe it as “barrel shaped.” A lot of people don’t have the same idea of what a barrel looks like. Perhaps a better description is that the diameter at the widest point is about the same as the height of the nut, cap excluded. In comparison, the White Oak acorn typically is higher than it is wide.
Acorns of the red oak group are different from those in the white oak group in many unseen ways. The red oak acorns have more tannins, substances that make them distasteful to humans. (They cause them to be astringent.) Red oak acorns take two years to mature and they do not germinate immediately, remaining dormant until spring.
White oak acorns mature in a single year and germinate in the fall if they have landed in a suitable location. (When placed on moist potting soil and kept at room temperature I have had them germinate after seven to ten days.) The white oak acorn has fewer tannins, making them preferred for immediate eating by squirrels.
Squirrels are acorn connoisseurs. They discriminate between red oak and white oak acorns, preferentially burying red oak acorns for retrieval during the winter, while immediately eating the sweeter white oak acorns. If the white oak crop is especially abundant Gray Squirrels will bite off the tip of the acorn where the embryo is and then bury the nut for later usage.

Fuzzy Oak gall
Galls. A gall is an abnormal growth of plant tissue and can be caused by a variety of organisms: viruses, bacteria, fungi and insects. Galls are the response of the plant to the infection or invasion of foreign material. Many insects, including a group known as the Gall wasps, family Cynipidae, have taken advantage of this response to provide their young with a source of food and shelter. The majority of Gall wasps use oaks as their host plant. Females insert their eggs in various parts of the tree, leaves, stems, buds, even roots, depending on the species. The presence of the egg stimulates the production of the gall by the host plant. When the egg hatches the larval wasp finds itself surrounded by a cozy mass of plant food which it promptly begins to eat. Each species of Gall wasp produces a unique type of gall. The exactly how this is accomplished is currently unknown.
The gall we found today was on the midvein of a White Oak leaf. Galls are difficult to identify but we think this was made by a wasp in the genus Callirhytis.
(An interesting tangent: Before he became famous for his research on human sexuality Alfred Kinsey was well know in entomological circles as an authority on Gall wasps. He described hundreds of new species and his collection of 5 million specimens now resides in the American Museum of Natural History.)

Several Ramblers had questions about fungi; here are some answers.

Why aren’t mushrooms considered to be plants?
When I was in high school fungi, including mushrooms, were considered to be plants. They obviously lacked chlorophyll but they produced spores, just like ferns and mosses. Like plants, their cells were surrounded by a cell wall. (Animal cells lack cell walls.) But plant cell walls are made of cellulose, whereas fungal cell walls are made of chitin, the same material that makes up the exoskeleton of arthropods (insects, crustaceans and similar creatures).
Fungi have a mode of nutrition that is called “absorptive.” The tips of the thread-like cells that compose the fungus body secrete digestive enzymes that break down the surrounding material (wood, dead or living plants and animals) into simpler substances that they absorb. (If the surrounding material is dead this is known as “rotting.”) Our stomach and intestines do the same thing, only we call it digesting. In both fungi and animals complex molecules in the environment are enzymatically reduced to simpler molecules that are taken into the body. Fungi do the digesting outside their bodies while we do it inside. Rotting equals digestion.
In recent years DNA analysis has revealed that the true relationship of the fungi is with animals, not plants. This means that fungi and animals shared a common ancestor more recently than they do with plants. In genealogical terms it’s like saying that fungi and animals share the same grandfather, but plants, fungi and animals have the same great-grandfather. But, of course, we’re talking about ancestors that are hundreds of millions of years ago.

Mushroom sex:
On a previous ramble I made a casual remark about some mushrooms that have thousands of different sexes. That idea tweaked the curiosity of a number of ramblers who deluged me with questions. Now I'll try to answer these, so, if you're not interested in mushroom sex, you can skip ahead to next topic.
First 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. The “body” of a flowering plant (its roots, stems and leaves) provides the nutrients to produce flowers and, ultimately, seeds. In a mushroom-producing fungus the part corresponding to the roots, stems and leaves is called the mycelium. It looks very different from a plant. You've undoubtedly seen a mycelium before. It is made of microscopically thin, thread-like cells, called hyphae (singular, hypha). Masses of hyphae make up a mycelium. They explore the material they are growing on – wood, dead leaves, bread, etc. – digesting it as they grow. Look at a piece of moldy bread. You’ll notice two things: a granular mass of spore, variously colored green, black or yellow, surrounded by a mass of fine white threads. Those threads are the mycelium of the bread mold. Similarly, the mycelium of wood-rotting mushrooms is made of 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 first has to meet and fuse with a mycelium of the same species but a different sex.
This makes the mushroom different from a flower. Flowers are produced in anticipation of sex; in fungi the sex precedes the mushroom. Here’s how it works:
Mushrooms are the result of a sexual act. But fungi 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 it happens to meet. 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 in some fungi there weren't just two mating types but many different ones. He further discovered that the mating type was genetically controlled and that the mating type genes were highly variable. A fungus can mate with any other type of fungus 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 the fungus he worked with. 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 completely 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 that will produce spores. Within each such cell 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 a mating type that is either like one of its parents or a completely new mating type. And the cycle of life continues.

Purple Trail:
Violet-toothed Polypore viewed from below. From above only the edge of the fungus is purple and this color fades with age.

Beechdrops
Beechdrops
We noticed Beechdrops beneath an American Beech. Recall that this flowering plant lacks chlorophyll and is a parasite on the roots of the beech tree.
We think the yellow granules in the calyx(?) cups of Beechdrops flowers are seeds. Other ideas are welcome.
The petals were gone, leaving only the calyx of the flowers. It was partially filled with yellow granular material, most likely seeds, but none of us were very confident about this interpretation. For more information about Beechdrops visit the October 25, 2018 blog post.
Look hard at this photo of hundreds of Beechdrops beneath a beech tree. If you're patient you'll be able to see them.
(Photo courtesy of Katherine Edison)
Nearby another American Beech was surrounded by an enormous number of Beechdrops stems. This photo, taken by Katherine Edison, shows them, but you have to study it before you actually see the hundred or so short stems protruding from the ground.

Crowded Parchment Fungus

Hornbeam Disk fungi

Hornbeam Disk fungi are most evident after rainfall. Between rains they dry out and shrink, only to be renewed again at the next rain. They appear to only feed on the bark of the host tree. The yellow droplets were only seen on one tree's fungi. We're not sure what they are or do.

False Turkey Tail
Coral Pink Merulius
Lumpy Bracket

Zoned Phlebia
At one location there was a pile of Oak branches and logs, nearly all supporting a variety of wood-rotting fungi: 
Violet-toothed Polypore, False Turkey Tail, Coral-pink Merulius, Hen-of-the-Woods/Maitake (old), Lumpy Bracket, and Zoned Phlebia.

Orange Trail:

Musclewood looks muscular, hence one of its common names; American Hornbeam is another; Ironwood, yet another.
Near the junction of the Purple and Orange trails is one of the largest Musclewood trees we've every seen. This species is typically found growing in moist environments like stream sides. The related species, Hophornbeam, has a broader tolerance. It's commonly found stream side to dry ridges.

Beaver chew marks on Chinese Privet growing on the river bank.
We always find a surprise on a Ramble and today's was the discovery of a Chinese Privet that had recently been sampled by Beavers. This might indicate that beavers are investigating the old Beaver Marsh that had a colony here twenty-plus years ago.

Several different White Asters are still blooming along the river and the dam at the Beaver marsh.

Brown heard a Common Yellowthroat Warbler at the beaver marsh.
A Cardinal Flower, still in bloom. A first(?) for the Garden.
He also spotted a blooming Cardinal Flower that may be the first seen in the natural area of the Garden.


Brown found a Blewit mushroom

Grape Fern with fertile frond

Closeup of fertile frond showing the sporangia, the spore-producing structures.
Grape Fern is a fall reproducing fern. There is a similar looking fern, Rattlesnake Fern, that appears in the spring and, like Grape Fern, has a separate fertile frond. The season of appearance is an easy way to identify them, but where the fertile frond appears is also key. In the Grape Fern the fertile frond appears next to come from the ground next to the plant. In the Rattlesnake Fern the fertile frond emerges from the sterile fronds. 

Orange Trail Spur (creek to Flower Garden):

The fresh leaves of our "Hughpatica," a Round-lobed Hepatica.
We always stop at the bridge to the Flower Garden to check on the Hepatica that grows on the west side. The first leader of the Nature Ramblers, Hugh Nourse, always checked on this plant to see when it first bloomed. Hugh and his wife, Carol, moved to St. Louis two years ago and are greatly missed. We've informally named this plant "Hughpatica" in his honor.

Wild Ginger also produces leaves that persist through the winter, but it blooms much later than Hepatica.

Gem-studded Puffballs

Stump Puffballs

Exit hole of Hickory Nut Weevil.

Many of the acorns and hickory nuts you find this time of year have tiny holes in them. These are caused by a weevil, a type of beetle, that has spent the summer eating the contents of the nut. The egg was laid in early spring when the host tree was flowering and the larva grew along with enlarging acor or hickory nut. Now it escapes the larder and crawls into the soil where it will pupate and spend the winter. Next spring it will emerge from the pupa as an adult weevil and, after mating, seek out more flowers to lay eggs in.

SUMMARY OF OBSERVED SPECIES:

Northern Red Oak
Quercus rubra
White Oak
Quercus alba
Gall Wasp (fuzzy gall)
Callirhytis sp.
Violet-toothed Polypore
Trichaptum biforme
False Turkey Tail
Stereum ostrea
Zoned Phlebia
Punctularia strigosozonata
Lumpy Bracket
Trametes gibbosa
Beechdrops
Epifagus virginiana
Crowded Parchment
Stereum complicatum
American Hophornbeam
Ostrya virginiana
Hornbeam Disk mushroom
Aleurodiscus oakseii
Coral-pink Merulius
Phlebia incarnata
Hen-of-the-Woods/Maitake
Grifola frondosa
Crossvine
Bignonia capreolata
Japanese Privet
Ligustrum japonica
North American Beaver
Castor canadensis
White Asters
Symphiotrichum sp.
Common Yellowthroat Warbler
Geothylpis trichas
Cardinal Flower
Lobelia cardinalis
Southern Grape Fern
Sceptridium biternatum
Blewit mushroom
Clitocybe (Lepista) sp.
Moss
?????
Round-Lobed Hepatica
Anemone americana
Wild Ginger
Hexastylis arifolia
Stump Puffball
Lycoperdon pyriforme
Gem-Studded Puffball
Lycoperdon perlatum
Hickory Nut Weevil
Curculio caryae
Giant Leopard Moth caterpillar
Hypercompe scribonia
Cranefly Orchid
Tipularia discolor