Ramble Report October 5, 2023

 

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.

Number of Ramblers today: 31

Today's emphasis: Warm season grasses and other sights in the ROW prairie

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 23^rd:

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 31^st.

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 16^th.

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.

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.

River Oats is a cool-season grass. Blooming in May, its flowers are long gone by now and its seeds heads are mature.

River Oats is a cool-season grass.
Blooming in May, its flowers are long gone by now and its seeds heads are mature.

Broomsedge may be the most common native grass in Georgia, blanketing abandoned fields and pastures and turning a beautiful coppery color in the winter.

Not so long ago, Broomsedge stems were harvested and tied together to make a homemade broom.

Broomsedge spikelets are held inside a slender, canoe-shaped structure called a “spathe.”

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.

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.

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.

Purple Top or Greasy Grass is named for the dark purple spikelets which are coated with wax that prevents them from drying out. The spikelets matured early this year due to the drought and are brown and not very “greasy.” Purple Top can be recognized at 55 mph – its seed head is triangular in outline and composed of delicate, gracefully drooping or arching branches.

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.

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.

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.

Common Checkered Skipper resting on the spent heads of a Late Boneset.

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.

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.

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.

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.

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

Scudder's Short-winged Grasshopper on
a Yellow Indian Grass leaf

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.

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.

The native Perennial Foxtail Grass seed heads have white bristles that shine in the sunlight.

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.

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.

Scarlet Morning Glory is still flowering in the prairie and still attracting the attention of sulphur butterflies.

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