Ramble Report September 22 2016

Today's Ramble was lead by Linda Chafin.

Here's the link to Don's Facebook album for today's Ramble. (All the photos, except those credited otherwise, in this post are compliments of Don.)

Today's post was written by Dale Hoyt, Linda Chafin and Don Hunter.

Attendees: 25

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Today's reading: Ed read excerpts from an article about recent discoveries in Lichen symbiosis in a recent issue of The Atlantic magazine. You can find the article here.

Don read a Robert Service poem, Fallen Leaves, appropriate to the first day of Fall. You can find the text of the poem here.

Today's route: We took a quick trip through the Shade Garden, stopping only to look at the Hurricane Lilies, then crossed the road on the White trail, turned off the trail briefly to examine the test plots for getting rid of Bermuda and Fescue grasses, then rambled up the Power line ROW before returning back to the Arbor.

Bald-faced Hornet (L) and European Hornet (R)

Hornets at the Arbor: The White Oak next to the Arbor is still seeping sap and the fermenting sap continues to attract a variety of insects. This morning the show consisted of European Hornets and a single Bald-faced Hornet. The larger Europeans succeeded in chasing off the Bald-faced.

Today's focus: Grasses. While we were still at the Arbor Linda passed around examples of three easily recognized grasses: River Oats, Yellow Indian Grass and Foxtail and told us a little about how grasses differ from other flowering plants. The flowers of grasses are much reduced. Being wind-pollinated they have no use for petals, nectaries or floral scents. A grass inflorescence consists of spikelets, each of which contains 1 or more florets. The group of spikelets that make up the flower cluster is also known as the seed head.

River Oats

In River Oats the groups of spikelets resemble fish, a similarity that gives rise to another common name: Fish-on-a-Pole.

Yellow Indiangrass seed with awn
(Sam C. Strickland, Lady Bird Johnson Wildflower Center)

Yellow Indiangrass flower with stigma and yellow anthers.
(Carolyn Fannon, Lady Bird Johnson Wildflower Center)

The spikelets of Yellow Indian Grass are much more diffusely arranged, creating a yellowish haze when viewed from a distance. Linda recommends a trip down GA-15 this time of year to see the numerous stands of Yellow Indian Grass on the roadside. An awn, bent at an angle, is attached to each seed. When the seed is ripe and falls to the ground the awn twists and turns in response to changes in humidity. This twisting action drives the seed into the ground and the bristles on the seed surface keep it buried.

Grasses are wind pollinated, so to ensure that each flower captures enough pollen to fertilize its ovum the stigma has an enormous surface area. It looks like a bottle brush hanging out of the spikelet. Similarly, the pollen dispensing anthers dangle out of the spikelet allowing the pollen free access to the air so it may be carried to the exposed stigmas of other plants plants.

Yellow Foxtail Grass

The Yellow Foxtail grass, a non-native, has a distinctive cluster of spikelets at the end of the stem. It looks like the bushy tail of a Fox. 

After this brief introduction we left the Arbor and hustled through the Shade Garden, stopping only once, near the bottom. 

Hurricane Lilies

At the bottom of the Shade Garden some Hurricane Lilies (also known as Surprise Lily or Red Spider Lily) are still blooming (we saw this group three weeks ago). These flowers are native to China and Japan and are in the Amaryllis family, which means that nearly every part is toxic – even deer will leave them alone. The Hurricane in the name refers to the late summer season in which the flowers appear, about the time when hurricanes or tropical storms begin to threaten the Atlantic coastal states. The odd thing about the plants is that the flower and foliage appear at different times of the year. The naked stems with their flowers emerge suddenly during late summer (the origin of the Surprise name) but the foliage only appears after the flowers are gone. It persists sometimes through the winter and then disappears in the spring. There is no sign of the plant during the summer until the flower stalk pops up again in August.

Japanese Stilt Grass (Nepalese Browntop, Microstegium)

Microstegium (Japanese Stilt Grass, Nepalese Browntop): This plant looks like a miniature bamboo. The midvein of the leaf is silvery or pale and shiny, and is slightly off center; the leaf blades are 2-4 inches long and about 1/2 inch wide. It is an annual plant producing numerous seeds that can remain dormant in the soil for up to 5 years. Control is achieved by pulling plants before they flower. Mowing is less effective because the plants simply flower on shorter stalks. The best control is preventing it from establishing. In addition to the long viability in the seed bank the seeds are tiny and easily transported on soil that adheres to shoes or automobile tires. Linda has observed Microstegium on the Appalachian trail where only hikers could have brought it in. 

Our expert on the control of invasive plants, Gary Crider, said that Microstegium can be controlled with an herbicide that is grass-specific. The active ingredient of one such product is Sethoxydim, a compound that inhibits the formation of lipids in grasses. (Lipids are components of cell membranes.) More information about Sethoxydim can be found at this Cornell University Weed Ecology and Management Laboratory website. Gary also says that this herbicide is available locally.

Grass removal test plots: Linda gave an overview of the Garden's native prairie conversion project. Over thirty years ago the area between the road and the White trail was planted in Bermuda grass. The first task in creating a native prairie is to get rid of the Bermuda grass, which is difficult to control because it is very resistant to most herbicides. The Bermuda eradication project is being funded by a grant from the Institute for Museum and Library Sciences. Different methods of removal are being tested in this area. When all the grass has been successfully removed from one of the plots the Garden is planting it with native prairie species to get them established. All the new plants were grown, plugged and planted by Heather Alley and her staff. Approximately half a dozen species have already been planted, including Yellow Indian Grass.

 

Cool and Warm season grasses. Two types of grasses are defined by their periods of active growth and flowering. Cool-season grasses start growth either during the winter or in early spring and flower in late spring. Warm-season grasses begin growth in spring and flower in late summer and fall.

More about Bermuda Grass
Following are excerpts about Bermuda grass from All About Weeds, by Edwin Rollin Spencer. First published (as Just Weeds) in 1940, before the use of chemical herbicides, it is of interest for the recommended methods of control, as well as the delightful writing style. The author is also willing to see several sides of a controversy. In this book weeds are neither wholly evil or wholly good. Spencer (Ph.D, University of Illinois) was a farmer as well as a Professor of Biology at what was then Southeast Missouri State Teachers College (subsequently Southeast Missouri State College and, later, University) in Cape Girardeau, Missouri.

   No one in the South has to be told what Bermuda grass is, but some Southerners should be told that it is not entirely a weed. That it is bad under certain conditions the most ardent advocate of the plant has to admit. It can take a cornfield or a cotton patch, and the farmer who hopes completely to eradicate it from his cultivated fields can expect to fight throughout a growing season, and be ever on the lookout every season thereafter.

   But Bermuda grass has virtues as well as faults. It is the peer of grazing grasses. It has no equal as a pasture grass, especially in the South. . . . It has two faults as a lawn grass: it starts late in the spring and it refuses to grow in the slightest shade. Of course, the lawn owner wants a grass that will shoot up green as soon as the growing season starts. The Bermuda grass will not do this, but in July and August when other lawn grasses have to be pampered the Bermuda grass is luxuriant.

   It is in the pasture that the Bermuda grass excels, however. A good field of Bermuda will pasture five head of cattle to the acre throughout the growing season. . . .

   For the information of him who does not know Bermuda grass it should be said that its general appearance is somewhat like that of Crab grass. It has the fingerlike fruiting top that the Crab grass has, but the fingers are smaller and much shorter than those of the Crab grass. They also extend out horizontally, almost perpendicular to the supporting stem. The leaves are not nearly so long as those of the Crab grass, and much finer in texture and there are runners sent out from the main bunches. . . .

   The prejudice against Bermuda grass has all come about because the southern farmer does not know how to keep it out of his cultivated fields. This is easily done by shallow plowing of the field just before the ground freezes in late autumn or early winter. After the ground freezes the Bermuda is easily killed. This one plowing, which turns the rootstalks up on top of the ground, and so destroys them by freezing, leaves little to be done except the essential cultivation of the next year. . . .

   The feeling against the Bermuda is so great that farmers in the South refuse to allow a field to produce Bermuda hay. They fight Bermuda all summer and buy hay all winter. Only the dairymen of the South seem to appreciate fully the value of this wonderful weed. Ten or twelve acres of Bermuda grass are the equivalent of five or six times that acreage of bluegrass or red top and timothy. . . .

   It is one of the very best plants to use for controlling soil erosion. Ditches may be actually filled by planting a few bunches of Bermuda grass in the bottoms of them. It will hold dams for impounding water almost as effectively as a concrete core and it can be used very effectively on terrace outlets or spillways. There are so many places where Bermuda grass will grow and serve the landowner that it is almost sacrilege to call it a weed, but what else is it when the enraged farmer finds that it has choked large areas of his cotton plants to death?

Beefsteak plant (Perilla mint)

On the way up the power line ROW Gary pointed out the Perilla mint (Beefsteak plant) that he and Linda agree is becoming another invasive species. It is widely used in Chinese, Korean and Japanese cuisine. There are reports in the United States of toxicity issues in cattle, but there is no clear evidence that all varieties of the plant or even all parts of the plant are responsible. These reports are at variance with the usage of the herb in Japan and Korea.

Grasses in the Elaine Nash prairie.

Several species are currently flowering or about to. Those that we took special note of were Purple Love grass, Purple Top (or Greasy grass), Little Bluestem, Beaked panic grass and Silver Plume Grass.

Purple Love Grass

 

Seed heads of Purple Top Grass (Greasy Grass)

 Purple Top Grass: Edwin Spencer (in All About Weeds) says that "Stock almost never eat it; never after its beautiful panicle of flowers is formed, for there is a viscid substance that issues from the branches of the panicle and from the stem below it, and that substance has a strange odor. It is the odor that gives the tang to the evening air that time of year; a peculiar, Oriental smell that is almost entrancing to some nostrils, but is evidently disgusting to those of grazing stock. For this reason it is on the increase. Nearly every roadside is lined with it now, and it is likely to be seen in partially grazed pastures, in neglected town lots and in unmown farm fence rows."

Little Bluestem flowers; when tapped clouds of pollen are released from the brown anthers and float away.

 

Silver Plume grass; note the tiny stamens hanging from the flower spikes.

 

 

Gulf Fritillary; compare the upper surface with the Variegated Fritillary.

Gulf Fritillary; silver spots are absent in the Variegated Fritillary

Variegated Fritillary

Variegated Fritillary: Last week we saw the distinctive  caterpillar of the Variegated Fritillary feeding on Purple Passionflower vines. Today we spotted an adult butterfly warming itself up in the sun. This species is a little drab, compared to the Gulf Fritillary -- it lacks the dazzling silver spots on the under surface of the wings. It has a larger host range -- the caterpillars can be found feeding on violets as well as Passionflower vines.

Potter wasp nests

Potter wasp nest. George discovered two small clay jugs, the work of a potter wasp. Even Alice was impressed with the workmanship. Each little jug was assembled from tiny globs of clay, carried one at a time by a single wasp builder. Once constructed the wasp provisions the little jug with caterpillar prey that she hunts and subdues with a sting. When the jug is full she lays a single egg and then seals the opening with a glob of mud. The wasp grub feeds on the caterpillar and, after pupating, has to chew its way out of the sealed nest. One of the two nests on the twig had several tiny holes in the wall. These were probably made by parasitoids that either fed on the potter wasp larva or on the paralyzed caterpillars in the nest.

Ailanthus Webworm Moth

Ailanthus webworm moth

This curious looking and colorful moth is commonly seen all summer into fall. It was originally found only in tropical regions, but began to appear when the Ailanthus tree was planted in the US. Ailanthus is native to China and became a popular urban tree because it was very tolerant of pollution. The moth discovered that it could feed on Ailanthus and has spread over the US where ever Ailanthus trees are available. The caterpillars tie several leaflets together to form a silken web or nest within which they feed. I have never seen an Ailanthus tree in Athens or the Garden, so I'm curious as to where these moths come from.

SUMMARY OF OBSERVED SPECIES:

Common Name	Scientific Name
European hornet	Vespa crabro
Bald-faced hornet	Dolichovespula maculata
River oats	Chasmanthium latifolium
Yellow Indian grass	Sorghastrum nutans
Yellow foxtail grass	Setaria pumila
Suprise lily	Lycoris radiata
Oyster mushroom	Pleurotus ostreatus
Japanese stilt grass	Microstegium vimineum
Fescue	Festuca sp.
Crab grass	Digitaria sp.
Witch grass	Dicanthelium sp.
Climbing milkweed	Gonolobus suberosus
Buckeye	Aesculus sp.
Beefsteak plant/perilla mint	Perilla frutescens
Variegated fritillary	Euptoieta claudia
Red morning glory	Ipomoea coccinea
Purple top/greasy grass	Tridens flavus
Broomsedge	Andropogon virginicus
Fountain grass	Pennisetum setaceum
Purple love grass	Eragrostis spectabilis
Split beard bluestem	Andropogon ternarius
Lacewing fly	Order Neuroptera
Potter wasp (flasks)	Eumenes sp.
White crownbeard	Verbesina virginica
Unknown caterpillar (on Smilax sp.)
Big top love grass	Eragrostis hirsuta
Gulf fritillary (chrysalis)	Agraulis vanillae
Silver plume grass	Saccharum alopecuroides
Beaked panic grass	Panicum anceps
Ailanthus webworm moth	Atteva aurea
Yellow crownbeard	Verbesina occidentalis
Little bluestem grass	Schizachyrium scoparium
Mountain mint	Pycnanthemum pycnanthemoides
Poverty grass	Danthonia spicata