Leader
for today’s Ramble: Linda
Authors of today’s Ramble report: Linda and Don. Comments, edits, and suggestions for the report can be
sent to Linda at Lchafin (at) uga.edu.
Insect identifications: Don Hunter and Heather Larkin
Link to Don’s Facebook
album for this Ramble. All the photos that
appear in this report, unless otherwise credited, were taken by Don Hunter.
Photos may be enlarged by clicking them with a mouse or tapping on your screen.
Today’s emphasis: Warm season grasses and
other sights in the ROW prairie
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| Ramblers gather at the Children’s Garden arbor. |
Reading:
Inspired by the Garden’s native plant sale, Donna brought a reading from Doug Tallamy’s Bringing Nature Home:
It
is increasingly clear…that much of our wildlife will not be able to survive
unless food, shelter and nest sites can be found in suburban habitats. Let’s
focus on the first of these essential resources: food. Because food for all animals
starts with the energy harnessed by plants, the plants we grow in our gardens
have the critical role of sustaining, directly or indirectly, all of the
animals with which we share our living spaces. The degree to which plants in our
gardens succeed in this regard will determine the diversity and numbers of
wildlife that can survive in managed landscapes. And because it is we who
decide what plants that we will grow in our gardens, the responsibility for our
nation’s biodiversity lies largely with us. Which animals will make it and
which will not? We help make this
decision every time we plant or remove something from our yards.
Unfortunately, because we have been so slow to recognize
the unprecedented importance of suburban gardens for the preservation of
wildlife, gardeners across the nation have been caught off-guard. We have proceeded with garden design as we
always have, with no knowledge of the new role our gardens play — and, alas,
it shows. All too often, the first step in the surburanization of an area is to
bulldoze the plant assemblages native to our neighborhoods and then to replace
them with large manicured lawns bordered by a relative few species of popular
ornamentals from other continents. Throughout suburbia, we have decimated the
native plant diversity that historically supported our favorite birds and
mammals.”
Linda also brought a reading inspired by today’s emphasis on fall-flowering grasses, an entry in Donald Culross Peattie’s An Almanac for Moderns: September
23rd:
How much of any landscape is due to the grasses is a quality that
the best descriptions rarely admit. Grass lends to any land that it inhabits something
ample and light. To the marshes, the reed grasses give long, slant,
rainy-looking lines. And from their grasses, the pampas and the steppes must
surely take fully half of their contours. It is in autumn that the grasses
hereabout [the North Carolina piedmont] come forth in their full beauty; they
fill the meadows like some fluid till they are become like wind-swirled living
lakes. But, above all, they give the meadow scene its dominant color. There is
not one of our sterile upland fields or abandoned farms where the beard grass, Andropogon, does not show its soft
terra-cotta sheaths, its glaucous blue stems, and woolly gray puffs of downy
seed half-bursting from the spike. The Purple-top Grass troops across the
fields, its purplish stems standing rank to rank, the panicles turning a dull
gold as the seeds fall, reflecting the mild sunlight of hazy Indian summer
mornings. In the woods and old fields, the Indian Grass has begun to bloom—as
enchanting as any flower that can boast calyx and corolla—with its golden brown
spikelets, its dangling orange anthers, the whole plant turning to
sun-burnished bronze in its old age.
Announcements and Interesting
Things to Note:
Cathy mentioned that Sandy Creek
Nature Center is having their annual bird seed sale, to benefit the center and
our local birds. To order, click here. The
deadline for ordering is October 31st.
The
second weekend of the Botanical Garden’s annual native plant sale begins on
Thursday, Oct 12, 4-6 p.m, continues on Friday, 4-6pm, and wraps up Saturday, Oct
14, 8-noon.
New York
Times columnist Margaret Renkl, author of The Comfort of Crows and Late
Migrations: A Natural History of Love and Loss will be speaking at the Athens-Clarke County
Library on Baxter Street on October 16th.
A recent study found that common compounds found in flowers become more
toxic to butterflies at higher temperatures, an unexpected effect of climate
change.
Today’s
Route: We took the White Trail spur to the power line right-of-way, where we turned north to visit the Elaine Nash Prairie,
then south to the newly created prairie south of the trail, then returned to the Visitor
Center.
OBSERVATIONS:
Before beginning our annual
rambler “grass class,” Linda reminded us of some “grass class” basics and
prompted some important observations from other ramblers. Grasses are wind-pollinated,
therefore have no need for showy flowers to attract pollinators. Instead, they
have tiny flowers (called florets) held in spikelets. All the same parts are
there as in typical flowers but they are much reduced in size and complexity
and have strange new names: glume, lemma, and palea.
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| River Oats spikelet in flower in May, with 10 florets |
Grasses also have distinctive
leaves that are divided into two parts, the leaf blade and the leaf sheath.
The blade is what we usually refer to when we talk about grass leaves. The
sheath is the lower part of the leaf and it tightly clasps the grass stem,
often covering the stem entirely for an inch or more. At the inner angle where the blade and the
sheath meet is a tiny, easily overlooked structure called a ligule. It may be a
delicate membrane, or a line of hairs, or a papery fringe, among other
types, but it is always present in some form or another and is an important
diagnostic feature for many grasses. The function of the ligule is unknown but
it may prevent rain and debris from getting down into the leaf sheath.
Grasses have two growth forms:
bunch grasses (all of Georgia’s native grasses) and turf grasses (all of
Georgia’s lawn grasses). All of Georgia’s turf grasses are exotic (think: Zoysia,
Bermuda, St. Augustine, etc.). Bunch grasses grow in bunches, aka tussocks and clumps.
The spaces between the clumps are important to our small wildlife animals,
providing fallen seeds, travel corridors, and safe nesting sites for many
birds, small mammals, and reptiles.
Bunch grasses typically have deep
roots – in midwestern prairies with deep topsoil, native grass roots may reach
six feet deep. In the Piedmont, topsoil was washed into the rivers and down to
the coasts two centuries ago. How deeply grass roots can penetrate the clay
subsoil we now have varies from site to site and depends on the type of clay
and the species of grass. Turf grasses have shallow roots that penetrate only a
few inches in any type of soil and contribute little organic matter to the soil.
Grasses also have two different
flowering times. Grasses that bloom in the spring are known as cool-season
grasses; grasses that flower in late summer/fall are called warm-season
grasses. Warm-season grasses conduct photosynthesis using a special method
(called C4) that minimizes water loss and allows them to be very productive in
high temperatures; after flowering their aboveground parts wither (in our
climate). Cool season grasses more or less shut down their growth during the
summer and resume growing in the fall when temperatures drop, often remaining
green and photosynthetic during our mild winters.
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| Broomsedge may be the most common native grass in Georgia, blanketing abandoned fields and pastures and turning a beautiful coppery color in the winter. |
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| Not so long ago, Broomsedge stems were harvested and tied together to make a homemade broom. |
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| Broomsedge spikelets are held inside a slender, canoe-shaped structure called a “spathe.” |
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| Long-horned Meadow Katydid on a Broomsedge stem. |
Broomsedge often grows with Split-beard Bluestem, a
similar grass in the same genus, Andropogon. From a distance, they look
much the same and both turn coppery in the winter. Up close, you can see two
important differences.
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| Splitbeard spikelets are not held in a spathe but are instead on a pair of short branches at the top of a slender, leafless stalk – the branches start out as a single unit, split apart as they mature, and finally look like a paintbrush after the seeds are dispersed. |
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| Splitbeard stems appears to be two-toned, but actually the stems are red and the leaf sheath that wraps the stem is blue-green. Broomsedge stems are uniformly green. |
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Purple |
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| Bigtop Lovegrass has also gone to seed early. Covered with dew, a roadside patch of Bigtop looks like a cloud of mist. Bigtop Lovegrass seed heads are up to 3 feet high and 1.3 feet wide. When mature, the seed head breaks off and tumbles across the ground, spreading seeds as it goes. |
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| A small Dog Fennel plant, part of an aggressive horde of this species that threatens to take over the powerline prairie. Roger shared a story from his early years working on his family’s farm in southwest Georgia. He and his fellow workers would stick Dog Fennel sprigs in their hat bands to repel annoying insects while they were working. |
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| Boneset (left) and Dog Fennel (right) are both in the genus Eupatorium, though vegetatively they are very different. Their similar flower heads betray their common lineage. |
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| Common Checkered Skipper resting on the spent heads of a Late Boneset. |
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| With its eight-foot tall stalks, Silver Plume Grass is the most conspicuous grass in the Nash Prairie. The seed head goes through several stages on its way to seed dispersal, beginning as a flattened, fan-shaped silvery-pink plume in September that narrows and turns tan as the florets mature, then explodes into a large silvery-tan plume loaded with hundreds of seeds. Each seed is tipped with hairs and a long, twisted bristle that give the plume a woolly look. |
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| Silver Plume Grass leaves are long and wide with a thick white midvein and a patch of hairs near the base. There are almost always some red damaged areas on the leaf. |
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| Beaked Panicgrass Its branches angle stiffly upward and the spikelets taper to a point like a bird’s beak. There are two tiny florets inside each spikelet. |
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| Bushy Aster is one of four fall-flowering, white-flowered asters that look very much alike.This species is distinguished by flower heads with 15-30 white ray flowers and blunt-tipped bracts surrounding the base of the head; its branches are stiff and covered with tiny, rough hairs. |
The disk flowers of many fall-flowering asters start out yellow in color then turn red after they are pollinated. This color change is thought to be a signal to pollinators
that the flower is closed for business–pollinators quickly learn to heed the
color change as an indication that nectar is no longer available. This benefits
both parties: pollinators don’t waste their time looking for nectar where
there is none, and the plant benefits by having pollinators directed to yellow, still viable
flower heads. Gary asked: what is actually involved in the color change,
chemically speaking? I found the answer to this
question a bit too close to biochemistry for my comfort level, but the short (and
inadequate) explanation seems to be that when pollination (or maybe fertilization)
takes place, it triggers changes in two of the plant’s hormones (probably auxin
and ethylene) which then alter the synthesis of pigments in the flowers.
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| Yellow Indian Grass seed heads are a beautiful golden yellow. Each seed is tipped with a bristle that is bent ninety degrees and “corkscrews” the seed into the ground as the bristle twists in response to changes in humidity. The leaves have an unusual ligule (below) that resembles a pair of upright terrier ears or a gun sight at the junction of sheath and blade.
Photo by Janie K. Marlow, Name That Plant.net |
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| Scudder’s Short-winged Grasshopper on a Yellow Indian Grass leaf |
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| Gary pointed out the two large Loblolly pines growing on the edge of the right-of-way that support old vines of Trumpet Creeper and Poison Ivy. Unlike English Ivy, whose evergreen leaves block sunlight during the winter and weigh down and eventually destroy trees, these two native vines are deciduous. Both provide important food for wildlife. |
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| Poison Ivy berries are an important food for birds, providing fat and protein to fuel fall migration. |
Two species of Foxtail Grass
occur at the garden, one native with white seed heads, the other European and
invasive with yellow seed heads.
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The |
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| The annual, invasive Yellow Foxtail Grass has yellow bristles. It has come to dominate the roadsides near the Botanical Garden and is invading the prairie. |
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| Some areas within the powerline prairie at the Garden have been invaded by American Burnweed, a native but very aggressive species in the composite family. Each flower head bears more than 100 seeds, each tipped with a pappus of long white hairs.
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| Scarlet Morning Glory is still flowering in the prairie and still attracting the attention of sulphur butterflies. |
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| Ramblers in the prairie |
SUMMARY OF OBSERVED SPECIES:
River Oats Chasmanthium latifolium
Broomsedge Adropogon virginicus
Long-horned Meadow Katydid Conocephalus
saltator
American Burnweed Erechtites
hieraciifolius
Purple Top/Greasy Grass Tridens
flavus
Bigtop Lovegrass Eragrostis
hirsuta
Splitbeard Bluestem Adropogon
ternarius
Dogfennel Eupatorium capillifolium
Common Checkered Skipper Burnsius
communis
Silver Plume Grass Erianthus
alopecuroides
Beaked Panicgrass Panicum anceps,
synonym Coleataenia anceps
Bushy Aster Symphyotrichum dumosum
Yellow Indiangrass Sorghastrum
nutans
Scudder’s Short-winged Grasshopper
Melanoplus scudderi
Loblolly Pine Pinus taeda
Poison Ivy Toxicodendron radicans
Trumpet Vine Campsis radicans
Perennial Foxtail Grass Setaria
parviflora
Yellow Foxtail Grass Setaria pumila
Red Morning Glory Ipomoea
hederifolia