Ramble Report July 15 2021

Leaders for today's Ramble: Dale & Don

Link to Don's Facebook album for this Ramble
Number of Ramblers today: 25
Today's emphasis: The Piedmont Prairie restoration and its wildflowers.
Reading:  Page read a short excerpt from Tracking Gobi Grizzlies by Douglas Chadwick.

Here's the deal with most of us grown-up naturalists.: While we can toss around Latin names and biological principles, there's a huge part of us that's still just an eleven-year-old on a treasure hunt. We'll keep going all day on the chance of turning over a stone or peering around a bend to something that makes us say, "Ooooh!" and then, if we're lucky, "What the heck is that: I've never seen anything like it before." This impulse defines all kinds of adventurers. The difference is that the naturalist is captivated by the mystery of organisms, their majesty/intricacy/oddity/fantasticality. And their behaviors: "What's it doing?"

 

Show & Tell  

One of our Ramblers, Rich Kimmich, sent me some photos of an unusual flower to share with you. A pair of Shasta Dasies that appear to be con-joined.

Conjoined Shasta Daisy flower heads?

The same pair of flower heads from the side.

The two flower heads appear to be sharing the same stem. The typical daisy has just one flower head per stem. I have no idea how this happened. Perhaps a split in the floral meristem? Your guess is as good as mine (maybe better).

Today's Route: The sidewalk from the Arbor to the mulched White Trail path to the Dunson Garden, exiting on the road, then down the road, passing the Clethra and the Passion Flower vines, then up the power line right of way, passing the White Trail into the shade. Then back to our cars.

OBSERVATIONS:

Purple Passionflower

Structure of a Purple Passionflower.
Beginning at the top:
1) Three club-shaped structures,
(the swollen ends are stigmas and the "handles" are the styles).
2) A slightly swollen ovary, anthers
3) Five stamens (filaments & anthers) only 2 are visible.
(photo by D. Hoyt)

Purple Passionflowers have an unusual floral structure. A vertical post rises from the center of the blossom, extending above the petals. About ¼ inch above the bottom of this post there is a circle of stamens with their anthers held horizontally, parallel to the floral disk. The distance between the anthers and the base of the flower, where the nectar is, is just right for large bee, like a Carpenter Bee, to contact the anthers when it visits to flower for nectar. On the other hand, a honeybee visiting the flower is too small to touch the anthers while getting nectar.

Above the circle of anthers the post is slightly swollen. This swelling is the ovary, where the ovules that will develop into seeds are found. Above the ovary the post splits into three parts, the styles, each ending in a swelling – this swelling is a stigma, the location where pollen must be placed to produce seeds.
 

Position of the Stigmas. When the flowers open in the morning the three styles are initially pointing upwards. In some flowers they remain in that position, whereas in others they soon bend downwards until their stigmas are at the same level as the anthers, in position to receive pollen. Flowers with upright stigmas are very unlikely to be pollinated because the distance between the stigma and the nectary where where the bees are foraging is too great for pollen transfer.

This video shows a Carpenter Bee getting nectar from a flower with flexed styles. (Please ignore the soundtrack on the video. I couldn't figure out how to remove it.) Notice two things: 1) the bee is just the right size to brush its thorax against the anthers as it moves around the flower looking for nectar and 2) the stigmas are at the level of the anthers so,  as the bee moves about the flower, its thorax comes in contact with the stigmas. When that contact happens pollen grains are transferred from the bee’s thorax to the sticky stigma.

Review of flowering plant reproduction, for those who don’t remember.The summary above just focuses on the formation of the plant embryo. The actual process of making a seed is more complicated, involving a process called "double fertilization." I'll explain that at a future date.

A pollen grain contains two sperm cells. One will fertilize the egg, the other will fuse with other cells of the ovule that will become the food for the developing  embryo. To deliver these sperms to an ovule in the ovary the pollen grain must first be placed on the stigma of the flower. There the pollen germinates and begins to grow a pollen tube. The tube grows through the style into the ovary, carrying the sperm cells with it. When the pollen tube reaches an ovule within the ovary it releases a sperm cell which then fertilizes the egg cell within the ovule. The other sperm cell fertilizes the cells that will make the embryo's food.

Flowers with styles pointing upward will not be fertilized because their stigmas are too far away from the bees foraging for nectar. Such flowers are functionally staminate, or male, because they can produce pollen and transmit it to Carpenter bees, but cannot develop fruits and seeds because pollen is unlikely to reach their stigmas. Thus, there are two functional types of Passion flowers: hermaphroditic or bisexual flowers that can produce seeds and pollen, and staminate, or male, flowers that produce pollen only. Note that this applies to flowers, not to entire plants. A given plant is capable of producing both types of flowers.
 

Bisexual Purple Passionflower.
The styles are curved so the stigmas can touch a nectaring Carpenter Bee.
(photo by D.L.Hoyt)

 

A Purple Passionflower with erect styles and a Carpenter Bee foraging for nectar. The stigmas are too far from the bee to receive pollen so the flower will not produce any fruit or seeds.
(photo by D.L.Hoyt)

Why should a passion vine produce male-only flowers? The flowers last only one day, so the energy required to make the flower is the same, no matter whether it is male or bisexual. The additional cost comes when the bisexual flower has been pollinated. Then it starts to form a fruit with a lot of seeds, a process that will take a month or more. Each fruit is a drain on the plants available energy; more fruits developing, less energy available to each one. If this idea is correct, you would expect passion flower plants to produce more male flowers as the season progresses.

To test this idea University of Florida researchers counted the number of each kind of flower in a patch of passion flowers over one growing season. In the second week male flowers outnumbered the bisexual flowers, approximately 170 to 150. In subsequent weeks the number of male flowers remained relatively constant (150-170) but bisexual flowers gradually decreased in number (from 150 to 75).  The growing season ended with male flowers twice as frequent as females.

The researchers also conducted a more direct test of their hypothesis by manipulating fruit production. Each day, after recording its sexual status, they clipped off the ovary of every flower that opened. These ovariectomized plants not only produced more flowers compared to the unclipped control plants (704 vs. 351), but they produced almost twice as many hermaphroditic flowers (63% vs. 36%). This is strong support for idea that the plants can manipulate the sex ratio of their flowers to adjust the number of fruits to the amount of resources available.

But why not just stop making flowers? That would leave all of the plants energy to the developing fruits. A plant has two ways of passing on its genes to the next generation: producing seeds and producing pollen. Making a flower is cheap compared to making a fruit. By making a male flower the plant continues passing its genes on via the pollen, thus increasing its chances of contributing some of its genes to the next generation. That’s what evolution is all about.
 

A pair of Extra-floral Nectaries at the base of a Purple Passiion flower leaf blade.

Extra-floral Nectaries (EFNs) are nectar producing tissues that are not located in a flower. They are often found on leaves but can be located in many different places. Passion vines typically have a pair of nectaries at the base of leaf blade. They are thought to attract ants and, in doing so, decrease the number of herbivores on the plant. One study tested the idea by removing all the EFNs from a group of Purple Passion flowers and leaving the control group undisturbed. Herbivore damage was less on the control group and higher on the experimental group. If you watch ants on a plant they are usually running here and there until they contact something edible. Ants are predators and being edible means being a bug or caterpillar or insect egg. These are either eaten on the spot or carried back to the nest. So anything that attracts ants will likely benefit a plant in the long run. It's like a doughnut shop giving free coffee and doughnuts to the police. They are less likely to be robbed.

An ant on Purple Passion flower leaves.

A Carolina Anole stopping for a sip of dew and, perhaps, a tasty insect on a Purple Passion flower.

Carolina Anoles don't (or won't) drink water from a container. They get their water from dew or droplets on vegetation. They also obtain water from their insect prey. If you keep pet anoles you will need to spray their terrarium with water each day and more frequently if your house is very dry.
 

Swamp Rose Mallow

SwampRoseMallow
 At the bottom of the Dunson Garden a Swamp Rose Mallow was sticking a single blossom through the deer fence, giving us an opportunity to look at the characteristics of the Mallow family (Malvaceae)

 

(Following is from the July 28, 2016, Ramble Report by Linda)

 

"An economically important family, the Malvaceae includes cotton, okra, and hibiscus, including the old fashioned landscape plant, Rose-of-Sharon or Althea (Hibiscus syriacus). Two mallow species were blooming at the lower end of the Dunson Garden:  Rose Mallow (Hibiscus moscheutos), with its white, purple-throated flowers, and Red Hibiscus (Hibiscus coccineus), with huge, deep red flowers.

We took a look at the characteristic arrangement of Mallow Family reproductive parts. The stalks of the stamens are fused into a column that surrounds the pistil and projects well out from the center of the open flower. Near the top of the column, the anthers curve outwards. Above the stamens, the stigmas emerge at the tip of the column. We tried to figure out how pollinators, in their quest for nectar, manage to brush against both the anthers and stigmas, which seem widely separated from the “eye” of the flower where nectar is produced in most flowers. A bit of internet searching later revealed that Hibiscus flowers don’t produce nectar, so the pollinators are not bumbling around at the base of the flower at all. Pollinators are interested only in the pollen and, in their climbing around the top of the column, manage to transfer pollen. Whew.

Finally, we took a look at another characteristic feature of the Mallow Family: the epicalyx. The flower has the typical whorl of colorful petals and green sepals, but surrounding the base of the calyx is another whorl of 8 or 10 narrow, green structures that curve up. Function?  Who knows? But this is another example of those ubiquitous structures called “bracts” that we see in so many flowering plants. A bract is a broad term used to describe any leaf-like structure associated with (but not part of) a flower, and can take a variety of shapes and sizes and colors (think: red leaf-like things surrounding poinsettia flowers)."
 

Hairy Cats Ear

Hairy Cat's Ear is easily mistaken for Dandelion, probably because they bloom right after Dandelion finishes and they both are found in disturbed areas, i.e., lawns. The flowers are very similar to Dandelion, but the flower stalks are quite different. Dandelion's flower stalk is tan and hollow and supports only one flower head. Cat's Eart has green, solid flower stalks that usually branch to support two or more flower heads.

Silvery Checkerspot

Silvery Checkerspot is very similar to another butterfly, the Pearl Crescent. The diagnostic character is also pretty esoteric. To see this you'll have to click on the photo above to enlarge it. Look at the hind edge of the second pair of wings. You'll see is is bordered with a series of white dash "-" marks, .Just inside the white dash marks there is a solid dark gray or black band that runs along the margin of the wing.Just inside the black marginal band is a series of black spots. On the right hind wing I count six of these spots. Look closely at the third spot from the left, It has an open, white center, making it more of an "o" than a spot. If you look at the upper surface of the left wing the second spot from the right has an open center. If the butterfly you're looking at is a Silvery Checkerspot at least one of those hind wing black dots will have an open center. 

Common Whitetail, male
Females have brown abdomen and extra wing bands on wing tips.

Common Whitetail is the dragonfly we often see on Rambles. Newly metamorposed males have brown abdomens, like the females. As they age the dorsal surface of the abdomen becomes white. Females do not undergo this change..

American Lady

The American Lady butterfly looks a lot like the Painted Lady. The surest way to distinguish them is to look at the underside of the hind wings. American Lady has two large "eye" spots; Painted Lady has a row small, approximately equal size eye spots on the margin of the hind wings. The two species are different in other ways:

Painted Lady is highly migratory and its caterpillar feeds on Thistles; American Lady is non-migratory and larval host plant is Pussytoes.

Leafcutter Bee

Leafcutter Bees gather pollen on the underside of their abdomen. They are about the same size as a Honey Bee, but are black and gray in color and lack the pollen basket on their hind legs. They are solitary bees, each female building and provisioning her own nest. The nest is in a hollow, usually in soft wood or a plant stem. The female cuts semicircular pieces from thin, smooth leaves and uses them to build a cell that contains one egg and pollen for her larva. They are efficient pollinators and used for some greenhouse crops.

Thynnid wasp

Thynnid wasps prey on the grubs of scarab beetles. The females of some species are wingless and the males carry them in the air while mating. When the female finds a beetle grub she stings it, paralyzing the grub. She then lays an egg on it and seeks out more grubs.
 

Mason Wasp

Mason Wasps (AKA Potter Wasps) are solitary wasps. Each female provisions her nest with prey items she stings and paralyzes. She lays an egg on one and then seals the chamber off with a plug of mud. Some Mason Wasps, like this one, use pre-existing cavities, like hollow plant stems or holes drilled in a block of wood. Other kinds build a beautiful, hollow spherical nest from mud. 

 

The "bird's nest" stage of Queen Anne's Lace.

Queen Anne's Lace scarcely looks like it did a few weeks ago. The flat topped, white umbels have collapsed inward, forming a "bird's nest." Later the "bird's nest" will relax and open up, freeing the bristly seeds to catch a ride on a passing item of clothing or a furry body.

It is considered a category 3 invasive in Georgia: 

"Exotic plant that is a minor problem in Georgia natural areas, or is not yet known to be a problem in Georgia but is known to be a problem in adjacent states." Georgia Exotic Pest Plant Council

Spittlebug concealed in its spittle shelter.

A spittlebug with its spittle removed.

Here is a great video about Spittlebugs. It should answer all of your questions.

Littleleaf Sensitive Briar

The following passage was sent to me by Rambler Toni Senori. It's from Evangeline, Part the Second, by Henry Wadsworth Longfellow

As, at the tramp of a horse's hoof on the turf of the prairies,
Far in advance are closed the leaves of the shrinking mimosa,
So, at the hoof-beats of fate, with sad forebodings of evil,
Shrinks and closes the heart, ere the stroke of doom has attained it

Blackberry Stem Gall

Galls are abnormal growths of plant parts. They can be caused by a variety of agents: viruses, bacteria, insects, mites. Many galls are caused by insects and have a consistent location and shape. How this is achieved is not, at present, known. It must be something that is unique to each different kind of insect that interacts with the plants hormones to produce such a consistent result. The Blackberry Stem Gall is produced by a small wasp in the family Cynipidae, a large family of gall-making wasps. These wasps insert one or more eggs into a plant part. The plant responds by producing an abnormal growth that shelters the wasp larva and provides it with food. After several molts the larva pupates and later the adult emerges and chews its way out of the plant.

Chicken of the Woods

This large mushroom was found growing at the base of a Northern Red Oak in the Dunson Garden. It may be parasitic on the tree. This species is reported to also be saprobic (feeding on dead material). It causes a brown rot.
  
SUMMARY OF OBSERVED SPECIES:
Sweet Pepperbush                      Clethra alnifolia
Eastern Carpenter Bee                Xylocopa virginica
Common Eastern Bumble Bee    Bombus impatiens
Purple Passion Flower                 Passiflora incarnata
Carolina Anole                             Anolis caroliniensis
Red ant                                        Hymenoptera: Formicidae
Swamp Rose-mallow                   Hibiscus moscheutos
Wild Petunia                                 Ruellia caroliniensis
Hairy Cat’s Ear                             Hypochaeris radicata
Mountain mint                               Pycnanthemum sp.
Yellow Crownbeard                       Verbesina occidentalis
Loblolly Pine                                  Pinus taeda
Poison Ivy                                     Toxicodendron radicans
Trumpet Vine                                 Campsis radicans
Carolina Desert Chicory                Pyrrhopappus carolinianus
Common Whitetail                         Plathemis lydia
Beebalm                                        Monarda fistulosa
American Lady                              Vanessa virginiensis
Silvery Checkerspot                      Chlosyne nycteis
Leaf-cutter bee                              Megachile sp.
Thynnid Wasp                               Myzinum obscurum
Mason Wasp                                 Euodynerus foraminatus
Queen Anne’s Lace                      Daucus carota
Spittlebug                                     Hemiptera: Cercopidae
Bowl-and-doily Spider                  Frontinella pyramitela
Littleleaf Sensitive Briar                Mimosa microphylla
Heal-all                                         Prunella vulgaris
Blackberry                                    Rubus sp.
Grey-headed Coneflower             Ratibida pinnata
White Thoroughwort                     Eupatorium album
Rosepink                                      Sabatia angularis
Chicken-of-the-Woods                 Laetiporus sulphureus
Chanterelle mushroom                Cantharellus sp.