Ramble Report July 6 2017

Today's Ramble was led by Linda Chafin.

The photos in this post, except where noted, came from Don's Facebook album (here's the link).

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

Thirty three Ramblers met today.

Today's reading:Linda read a poem: Insect Life in Florida by Lynda Hull.

 

Today's Route:   We left the Shade Garden arbor and headed down into the Shade Garden via the path to the right of the arbor.  We eventually took a left on the road, walking adjacent to the deer fence before heading down the access road to the Mimsie Lanier Center for Native Plant Studies.  After checking out a few plants just before the center, we then returned, via the road, to the parking lot.  Many of the Ramblers then headed into the Visitor Center for some refreshments and conversation at Cafe Botanica.

Shade Garden Arbor:

Carolina Wren nest

Jeff brought a Carolina wren nest he retrieved from his barbecue grill. Carolina wrens are famous for building their arch-shaped nests in human-made habitats, e.g. mailboxes, outdoor hanging plants, and backpacks left on the back porch over winter. Carolina wrens form life-time pair bonds and build their nests together. They also fill nearby nest sites with mosses, leaves and twigs. These dummy nests either distract potential predators away from the real nest or prevent other birds from nesting in the same territory. Or, perhaps, both. Jeff also told us that if a nest with eggs is moved the parents won't be able to find it and will start a new nest. But if the eggs have hatched and the young wrens can vocalize the nest can be moved and the parents will find it and continue to feed their young.

Richard brought some strands of Dodder growing on Beefsteak Plant, also known as Shiso in its native southeast Asia; in this country, Beefsteak Plant is invasive. Dodder is a native plant that lacks roots and chlorophyll and must parasitize other plants for the basics of life. Dodder begins its life rooted in the soil and, following chemosensory cues, it grows toward a nearby plant. If it doesn’t reach a host plant within a few days, the Dodder plant will die. But if it does reach a host plant, it sinks its haustoria (root-like appendages) into the vascular system of its host and begins extracting food and water. The original root withers away and the plant loses all connection to the soil.

Dodder species are found worldwide and are not picky as to their host plants; in Georgia we have seven or eight Dodder species, all in the genus Cuscuta. None of them are dangerous parasites and all seem to be pretty well behaved, co-existing sub-lethally with their hosts. One species, Harper’s Dodder, is rare and considered a species of Special Concern. All of our Dodder species have orange, twining, leafless stems, and produce small white flowers and fruit packed with thousands of long-lived seeds.

Some of the common names for Dodder are wonderfully evocative: scald-weed, beggar-weed, lady's laces, fireweed, wizard's net, devil's guts, devil's ringlet, gold-thread, hair-weed, hellbine, love-vine, pull-down, strangle-weed, angel hair, and witch's hair.

Tree rings (numbered by Don)
The last ring (#64) is the minimum age of this tree.
Since the cut is about 20 feet above the ground the tree is actually older by perhaps 10-20 years.

The area around the Arbor and the Arbor itself was battered by a number of blown-down trees that were victims of Tuesday's July 4^th storm. Where the downed trunks had been sawn through horizontally, the annual growth rings were exposed and easy to count. But which rings to count? Light rings alternate with dark rings–what’s the difference and should we count both when determining the age of the tree? The light-colored ring is formed by cells laid down early in the growing season and are known as “springwood.” Adjacent to the light ring and closer to the outer surface of the tree is a darker ring of “summerwood,” laid down later in the year. Springwood cells are large with thin cell walls and larger cavities, so this ring appears porous. Summerwood cells are smaller with thick cell walls, and this ring is therefore denser than the springwood. You can easily see this difference between the rings with the naked eye. The difference in color is due to the difference in cell wall thickness. (During the walk, Linda stated that the summerwood cells contain more tannins and resins but that was incorrect–she was mistakenly thinking about the difference between sapwood and heartwood–a topic for another ramble!) The take-home message is:  to figure out the age of a cut stump count either the light rings or the dark rings, but not both.

The width of both the springwood and summerwood rings tells us about the weather during those months–warm, moist seasons produce wide rings; droughts result in narrow rings. Crowded trees that are competing for light, water, and nutrients will also lay down narrower rings.

Annual growth rings are found only in trees in temperate zones, where there is a big difference among seasons. And they are only found in dicots, not in monocot trees such as palms and cordylines. In dicots, annual growth rings are formed in both hardwoods (oak, hickory, beech, elm, ash, etc.) and softwood species. They are also formed in pines, which, of course, are not dicots.

The cut surface of the fallen trees also shows how trees grow in diameter. Trees grow in two directions: height of trunk/length of branches and girth/diameter of trunk and branches. Growth in height and length occurs at the tips of twigs and roots in zones of rapidly dividing cells called apical meristems. Diameter growth is a little harder to visualize but is fascinating. It occurs just below the bark in a zone called the cambium layer. The cambium is like a sleeve or tube that completely encloses the trunk, the branches, and the twigs just under the bark, but you can’t see it with the naked eye because it is only one cell thick. The cambium sleeve consists of unspecialized cells, similar to stem cells, which divide inward to produce xylem (water-conducting tissue) and outward to produce phloem (sugar-conducting tissue). The result is (1) a core of xylem (“wood”) and (2) another “sleeve” consisting of several layers of phloem cells just under the bark. Now, to complicate matters further, there is another layer of cambium outside the phloem that produces cork cells; cork cells plus phloem make up what we call bark. The ridges, furrows, plates, scales, etc., that we rely on to identify a tree are formed as the wood core thickens, pushing outward against the bark and splitting it. Different tree species have adapted to this growth pressure in different ways. Some trees’ bark splits vertically to accommodate the growth, such as White Oak and Shagbark Hickory. Some trees have deep furrows formed by the outward pressure. Some trees’ bark splits both vertically and horizontally, forming blocks or plates, such as Persimmon or Dogwood. In trees like Beech the bark cambium keeps up with the growth in circumference of the tree, forming a smooth, gray bark surface. As the inner wood expands throughout the growing season, trees are continually sloughing off bark. The pattern formed by the sloughing – the way of accommodating to the growth pressure – is encoded in a tree species’ genetic makeup and varies little from individual to individual within a species.

The downed tree we examined is a Northern Red Oak, as are many of the other trees that came down in this storm. It seems this species is particularly susceptible, in our part of its range, to coming down in strong winds and appears to have a shallow root system. Speculation is that the trees, which are more common in northern climes, normally grow where topsoil is deeper and less clayey, allowing deeper development of root systems.  The root balls of Northern Red Oaks in our area are not so much balls as pancakes, resting on the hard Georgia clay. It’s also possible that Northern Reds, often the tallest tree in our forests, are more vulnerable to wind throw because their crowns are exposed above other canopy trees.

Deer Fence/Road down to ROW:

As we walked down the road, we stopped to admire the white flower clusters of Coastal Sweet Pepperbush that are growing through the deer fence.  It has just begun to bloom. We noticed that plants along the fence that receive more sunlight are bearing more flowers than those deeper in the forest.

Passionflower fruit

The Passionflower vines growing on the deer fence are in all life stages, from buds, to flowers, to nearly ripe fruit. Later in the season, the fruits will be edible, with a limey, sweet-tart pulp. Also later in the season, the caterpillars of Gulf Fritillaries will appear and eat most of the leaves. None of the life stages of Gulf Fritillaries, egg, caterpillar, pupa or adult, can survive our winters, so we have to wait for butterflies to fly up from Florida or south Georgia, find our Passionflower vines and lay eggs on them.

Scarlet Hibiscus

Three species of Hibiscus are in flower in the wetland at the west end of the Dunson Native Flora Garden. The red-flowered species is named, fittingly, Scarlet Hibiscus. The plants bearing white flowers with maroon centers are Comfort Root or Pineland Hibiscus. The pink-flowered species is Smooth Rose Mallow or Halberd-leaf Marsh-mallow. Linda gave us a refresher on the distinctive flower structures of hibiscus flowers: the epicalyx and the fused tube of stamens surrounding the pistil.

Some ramblers noticed the feeding activity of the Fall Webworm moth on a couple of branches of Deciduous Holly that were poking through the deer fencing. A colony of these caterpillars has surrounded the ends of the branches with silk webbing, allowing them to feed on the enclosed leaves with protection. . Auburn University has detailed information on the natural history of this species.

Scarlet Bee-balm balming a Carpenter Bee

A patch of Scarlet Bee-balm is in full bloom and attracting carpenter bees. The red tubular flowers are also hummingbird magnets.

American Wisteria

American Wisteria twines around the split rail fence next to the Bee-balm. Linda discussed the differences between American Wisteria (flat-edged leaflets) and Chinese Wisteria (wavy-edged leaflets).

Road from ROW down to Mimsie Center gate:

Carolina Desert Chickory

Linda pointed out that the yellow flower heads seen along the roadside belong to Carolina Desert Chicory, aka False Dandelion. The flower heads resemble those of Dandelions and Spotted Cat's Ear, both of which are invasive Eurasian species that have golden yellow flowers. Carolina Desert Chicory flowers are an unusual pale shade of yellow. The flower head is unlike other members of the Aster family that have two kinds of flowers: ray and disk. Like those of Dandelions they are composed entirely of ray flowers, with no central disk flowers.

Ephemeral pool

Blue Dragonfly

As we passed the right-of-way and headed towards the Mimsie Lanier Center, we noted the small ephemeral pool on the north side of the road next to a large Box Elder.  Several blue dragonflies were flitting around the water. Dragonflies have aquatic larvae that normally take a long time to reach metamorphosis into the adult stage. Ephemeral waters, like this pool, don't usually last long enough for them to complete their life cycle. Apparently humans are not the only animals that can engage in wishful thinking.

A shy Eastern Box Turtle tucked away from sight.

A female Eastern Box Turtle was discovered in the grass below a large Box Elder tree. Box turtles can completely withdraw into their shell when they feel threatened. The lower part of the shell, called the plastron has a hinge that runs from side to side. When danger approaches the turtle draws its head and forelimbs inside the shell and the anterior part of the plastron is pulled upward, completely sealing the front opening of the shell. The tail and hind legs are similarly protected by the closing of the posterior part of the plastron.

The sex of a box turtle can be determined in two ways: the eye color is red in males and brown in females, and the posterior part of the lower shell is flat in females and has a shallow depression in males.

Opened Cottonwood leaf petiole gall
The numerous tiny gray objects are aphids
The object at the top with white projections may be a beetle larva feeding on the aphids (or maybe not -- high uncertainty)

The same gall with a winged aphid visible among the many smaller white aphids.

Roger picked up a twig that had fallen from the large cottonwood tree located near the south side of the road. The leaf stalks are flattened, which allows the leaf to tremble and rustle in the wind. A round, green gall on the leaf stalk at the base of blade was opened and revealed lots of tiny aphids feeding in the interior of the gall. In addition, there was small, circular mass with many white bumps that resembled the larva of the Mealybug Destroyer beetle, as well as a large, winged aphid. There are aphids in the genus Pemphigus that commonly produce leaf galls on poplars and cottonwoods. These have complex life histories that involve two hosts, the cottonwood and another plant, usually in the cabbage or mustard family. In the mustard host the aphid is a root parasite; it is a gall maker on the cottonwood. To get from one host to another winged forms have to be produced that then fly to the alternate host and lay eggs. The young aphids that emerge from the eggs are wingless and reproduce asexually. Eventually they produce winged forms that reproduce sexually and fly to the alternate host.

The biggest mystery inside the gall was the object with little white bumps. If it was the larva of the Mealybug Destroyer I have no clue as to how it got inside the gall. It remains a mystery to me. I'm open to suggestions (dlh).

Buckthorn flowers

A Buckthorn shrub is blooming on the north side of the road to the Center. It has numerous confusing common names such as Buckthorn Bumelia, Buckthorn Bully, and Carolina Buckthorn (the last being a name also applied to a completely unrelated shrub–grrrr!). The white flowers are tiny and held in clusters that arise near the tips of short shoots, just below a cluster of leaves. The twigs are often tipped with thorns.

A small Leaf-footed bug nymph

Nathan spotted a small nymph stage leaf-footed bug, a true bug, on Don's shoulder. 

A red spotted purple butterfly passed by too quickly to be photographed.

Mimsie Center road, inside gate:

River Oats on the roadside have recently finished blooming, their green “fish on a pole” flower clusters dangling in the wind. Last year’s brown fruiting clusters were also still hanging onto several plants. Linda pointed out that River Oats are known to outcompete Japanese Stilt-grass and recommended planting them where the invasive grass is a problem (which is everywhere).

Sensitive Briar flower

Eastern Sensitive Briar is flowering in the ditch on the north side of the road. Like its relative, the Mimosa Tree, Sensitive Briar’s leaves will fold up when touched, a defensive mechanism that supposedly discourages herbivores. Both Sensitive Briar and Mimosa Tree have pink, puffball flower clusters composed of many pink stamens but without petals. The stamens are tipped with yellow, pollen-bearing anthers.

Silvery checkerspot butterfly on Rattlesnake Master

Large numbers of Silvery checkerspot butterflies were nectaring on both Rattlesnake Master and Mountain-mint flowers. They are abundant because the part of the ROW in the floodplain has so many Wingstem plants, the larval food of the Silvery checkerspot.  

Nathan pointed out all of the crickets present in the wet ditch.

We saw a Mississippi kite flying around the area between the Mimsie Center and the river.

Dallisgrass flowers; the fuzzy black things are the stigmas; the brown dangly things are the anthers.

We stopped to look at two common exotic roadside grasses: Vasey Grass and its close relative, Dallisgrass, both of which are native to tropical South America.

Yellow-lined Army worm on Ironweed

Ironweed and Butterfly Weed are in flower in the roadside bed. A Yellow-lined Army Worm was found on the Ironweed flower. The University of Florida has more information on the natural history of this species.

A small mint, growing on the back of the ditch proved to be an accidental import from an old meadow seed mixture.

Cicada

 

Jeff pointed out a cicada in a small fruit tree off the lower side of the road.

SUMMARY OF OBSERVED SPECIES:

Dodder	Cuscuta sp.
Beefsteak plant	Perilla frutescens
Northern red oak	Quercus rubra
Coastal sweet pepperbush	Clethra alnifolia
Passionflower	Passiflora incarnata
Scarlet Hibiscus	Hibiscus coccinea
Comfort Root/ Pineland Hibiscus	Hibiscus aculeatus
Smooth Rose Mallow/ Halberd-leaf Marsh-mallow	Hibiscus laevis
Scarlet bee balm	Monarda didyma
Fall Webworm	Hypantria cunea
Deciduous holly	Ilex decidua
Carpenter bee	Xylocopa virginica
American wisteria	Wisteria frutescens
Carolina desert chicory	Pyrrhopappus carolinianus
Dandelion	Taraxacum officinale
Spotted Cat's Ear	Hypochaeris radicata
Blue dragonfly	Order Odonata
Box elder	Acer negundo
Eastern box turtle	Terrapene carolina carolina
Nine-banded armadillo/ digging	Dasypus novemcinctus
Buckthorn Bumelia/ Buckthorn Bully	Sideroxylon lycioides
Eastern cottonwood	Populus deltoides
Leaf-footed bug (nymph)	Family Coreidae
Red-spotted purple butterfly	Limenitis arthemis astyanax
River oats	Chasmanthium latifolium
Japanese Stilt Grass	Microstegium vimineum
Eastern sensitive briar	Mimosa microphylla
Mimosa tree	Albizia julibrissin
Silvery checkerspot	Chlosyne nycteis
Mountain mint	Pycnanthemum sp.
Rattlesnake Master	Eryngium yuccifolium
Wingstem	Verbesina alternifolia
Cricket	Family Gryllidae
Mississippi kite	Ictinia mississippiensis
Vasey grass	Paspalum urvillei
Dallisgrass	Paspalum dilatatum
Ironweed	Vernonia acaulis
Butterfly weed	Asclepias tuberosa
Yellow-striped armyworm	Spodoptera ornithogalli
Mystery mint	??
Cicada	Neotibicen sp.
Cottonwood gall aphid	Pemphigis sp.