Ramble Report August 11 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 in this post are compliments of Don.)

Today's post was written by Dale Hoyt.

Number of attendees: 24

Announcements:
 

Thank you, Ed and Sue!!

Find the item you've been longing for!
Help out the SBGG!

Today's reading: Linda read a poem from The Writer's Almanac: From a Country Overlooked, by Tom Hennen:

There are no creatures you cannot love.
A frog calling at God
From the moon-filled ditch
As you stand on the country road in the June night.
The sound is enough to make the stars weep
With happiness.
In the morning the landscape green
Is lifted off the ground by the scent of grass.
The day is carried across its hours
Without any effort by the shining insects
That are living their secret lives.
The space between the prairie horizons
Makes us ache with its beauty.
Cottonwood leaves click in an ancient tongue
To the farthest cold dark in the universe.
The cottonwood also talks to you
Of breeze and speckled sunlight.
You are at home in these
great empty places
along with red-wing blackbirds and sloughs.
You are comfortable in this spot
so full of grace and being
that it sparkles like jewels
spilled on water.

Today's route: Through the Shade Garden on the cement sidewalk, then into the Dunson Native Flora Garden (DNFG) and out to the road and back to the parking lot.

Today's focus was on shrubs, so we needed to discuss what shrubs are. They are surprisingly hard to define, probably because they are really not clearly 100% separable from trees. Shrubs are generally thought of as woody plants that grow from multiple stems and do not reach a height of more than 20 feet. Several ramblers offered counter-examples, illustrating the difficulty of finding a precise definition. It is true that a shrub can be pruned to the shape of a tree, but that doesn't really count. Trees usually have a single stem and, when mature, are greater than 20 feet tall.

Piedmont azalea showing the flat whorl of leaves typical of native azaleas.

Piedmont azalea; note the hairy stems and twig

Piedmont or Pinxter azalea is the most common native azalea in our area. It has fragrant, pale pink flowers that, along with young twigs, are covered with sticky hairs.

Japanese camellia is in the same genus as tea (Camellia sinensis), but is grown for its foliage and flowers. It is not used for tea. We discovered two fruits on the shrub and cut them open, revealing four hard seeds.

Bottlebrush buckeye is native to the southwestern corner of Georgia and adjacent Alabama (with a disjunct population in west-central South Carolina). It has finished flowering for the year but we saw one in the Dunson Garden that had produced a number of fruits. These were located toward the top of the inflorescence, not toward the bottom as the references say they should be.

American Witch Hazel conical galls produced by an aphid.

American Witch Hazel always makes us wonder how it got its name. Last year (October 22) Catherine read a passage from Mary Durant's Who Named the Daisy? Who Named the Rose?, p. 210, 1976, Dodd, Mead & Co., that explained it all:

“WITCH HAZEL has nothing whatsoever to do with witches, despite the plant's mystic knack as a divining rod for water and precious ores. The old name is quite prosaic, no magical spells here. Witch comes from wych, a variant of the Anglo- Saxon wican, to bend. (This is also the root word for wicker, which is woven from bendable or pliable branches.)

The name witch-hazel was given to the shrub because the leaves resembled those of the English elm tree with long, drooping branches that was known as the wych-elm; that is, "the bending elm." And the wych-elm was also called wych-hazel, because its leaves resembled those of the hazel tree. (The origins of elm and hazel, both Old English, are uncertain.) Over the years, "wych" was transformed into "witch." (The other kind of witch comes from the early English wicca, a wizard.)

Today we saw cone-shaped galls on the leaves and a few scattered fruits. The galls form when the witch-hazel cone gall aphid (Hormaphis hamamelidis) crawls into the leaf bud in the spring. As the leaf grows, the aphid injects a substance, possibly an enzyme or hormone into the tissue, which causes the gall to form around her.  She produces 50 – 70 offspring, beginning four cycles of reproduction on the host tree, allowing the aphid to increase its population dramatically in a relatively short period of time. Reproduction is parthenogenetic, meaning the female can produce offspring without any male contribution. The aphids have not completely abandoned sexual reproduction, however. At certain times of the year they produce winged males and females (parthenogenetically!) that mate and the females fly to alternate host plant, a Birch tree. There they lay eggs that overwinter and in the spring the young aphids again produce a winged generation that flies to the Witch Hazel to begin the cycle again.

The American witch hazel is almost unique in flowering in the late fall into winter, with beautiful yellow flowers with four twisted ribbon-like petals, when other plants are becoming dormant. They are pollinated by winter moths that are adapted to flying in cold weather. The fruits take most of the year to develop and finally ripen in autumn. The seeds are under pressure and as the fruits dry out they are explosively ejected considerable distances.

Sweet pepper bush inflorescence

Sweet pepper bush developing fruits

Sweet pepper bush mature fruits resemble peppercorns, perhaps the source of the common name.

Sweet pepper bush is widely used for landscaping and is native to the coastal plain. The inflorescence is a four-inch, spike-like raceme covered by tiny, white, sweet smelling flowers. The Mountain sweet pepperbush (Clethra acuminata) has similar flower clusters but is taller and has stout stems with reddish, peeling bark.

Small anise tree or yellow anise tree has become very popular in the nursery trade. In spite of the name, it is regarded as a shrub, forming multi-stemmed clones. It bears small, yellowish-green flowers that produce unusual looking, star-shaped fruits similar to the familiar spice, Chinese Anise. Anise trees, Beauty berries, and Pawpaws are in plant families thought to have been among the earliest evolving flowering plants. They all have flowers that are dark maroon in color and smell strongly of rotting or fermenting substances that make them attractive to beetles and other insects that were around in the early Cretaceous.

The hollow stem of Pipestem

Pipestem is a plant with essentially hollow stems (there are scattered bits of pith called diaphragms). It is rare in GA, found only in the extreme southeastern counties, but is very abundant in northeast Florida's wet ravines and hammocks.

American beautyberry developing fruits;
in a few weeks these will be a brilliant purple.

American beautyberry has fuzzy stems and is now developing green fruits that form rounded clusters on the stems at the leaf nodes. These will develop into beautiful purple fruits later in the fall. It recently has been moved from the Verbena family and is currently assigned to the Mint family, but in other ways does not resemble a mint. (It does not have the typical two-lipped mint flowers, nor the square stems.)

Yaupon holly leaves; enough caffeine to wake you up just by looking at them.

Yaupon holly is one of the few North American native plants that is a source of caffeine. It was used by the Cherokee and Creek tribes as a ceremonial drink, taken in large quantities to induce vomiting, hence the scientific name: Ilex vomitoria. The leaves are parched then infused to make a tea. The stronger the tea the more caffeine. It was known to Native Americans as “the black drink.”

Dwarf Pawpaw leaves; smell the green pepper!

Dwarf Pawpaw leaves smell like green peppers. The buds are naked, i.e. they lack bud scales but are somewhat protected from freezing and desiccation by a dense coating of hairs. Dwarf pawpaw is a diminutive version of the Tall pawpaw planted in the Heritage Garden. Although the fruits are said to be tasty, the raccoons and squirrels usually beat the humans to them.

Crane fly orchid flowers

The difficult-to-find Crane fly orchid was seen in several places in the DNFG. The tiny mauve and tan flowers that adorn the foot-high stem blend in with the grays and browns of the leaf litter. Only the sharpest eyes are able to pick them out. These plants will be replaced by a single leaf that appears later in the autumn and will remain on the surface of the leaf litter all winter, disappearing late the next spring.

Georgia hackberry is a shrubby version of the much larger tree, the Southern Hackberry. Its leaves are sandpapery rough.

Ovate catchfly flowers; notice that each petal is split into four parts.

Ovate catchfly is rare in GA, found in only 10 counties, including Clarke. The plant has only five petals, but each one is split into multiple strips, making it appear to have numerous narrow petals. In the mountains there is a similar looking plant, Starry campion, but it has leaves in whorls of four.

Many of the catchflies have sticky hairs that catch insects, a feature that is seen in many other, unrelated plants. For a long time, people have thought that the presence of dead insects stuck to the stems of such plants might encourage ants to visit and thereby function like extrafloral nectaries. That is, by attracting ants the plants gain protection from herbivore that might be deterred by the presence of ants on the plant. This idea has been recently confirmed by studies in which the dead insects were removed from some plants and not others. Those with no dead insects attached to their stems suffered more herbivore damage than those that were untouched.

Plumleaf azalea; notice the stamens and pistils held far in front of the petals.

Plumleaf azalea, like all our native azaleas is deciduous with new leaves emerging in a flat plane at the tips of twigs. But, unlike other native azaleas, this species blooms late in the summer. It is found only in the ravines of Flint and Chattahoochee river basins in GA and adjacent AL. The reproductive parts of the flower–the stamens and pistil–project far from the petals, making it unlikely that bees or flies (which would be probing the base of the flower tube) would be successful pollinators. Recent research has revealed that large butterflies, like Tiger swallowtails, are effective in pollinating this plant, but with a wrinkle – the pollen is not transferred to the body of the butterfly, but to the wings! Swallowtails flap their wings while sipping nectar and the projecting stamens and pistil come in contact with the upper wing surfaces.

Woodland spider lily; stamen filaments are broadly attached to the white cup at the flower base.

Woodland Spider lily is related to the Shoals spider-lily in the genus Hymenocallis, which means beautiful membrane. This refers to the cup to which the stamens are fused. Like many of the lilies and other monocots the floral parts are in groups of three: three sepals and three petals. But the sepals and petals look very similar and are collectively referred to as "tepals." The leaves have parallel veins, like a typical monocot. Each flower opens for a single night and fades the following day. They are pollinated by moths. In spite of its name, spider-lily is not a true lily. In fact, it is in the Amaryllis family.

Leatherwood is named for its unusually flexible branches – they can be tied into a knot without breaking. This is a Northern plant – Georgia is in the southern part of its range, which also includes FL panhandle, AL, and a disjunct population in OK.

Devil's walking stick has huge bipinnately compound leaves.

Here's the stem. Now you know why is called Devil's walking stick.

An old inflorescence still has a few purple berries

Devil's walking stick has the largest compound leaf of all North American flowering plants. The leaf is enormous and bipinnately compound, meaning that each primary "leaflet" is pinnately arranged on the petiole and is further subdivided into smaller, pinnately arranged leaflets. The name refers to the thorny stem. The plant we examined still had the remains of flowers. The flower stalks turn pink and bear purple berries. This plant spreads aggressively, so it is best grown in pots or where it can be easily controlled. It is in the same family as the herb ginseng.

Alabama croton, Croton alabamensis, does not occur naturally in GA and was planted here in the DNFG. It occurs naturally in central AL on limestone glades and in dry woodlands and ravines over limestone. It’s a beautiful shrub with its leaves densely covered with silvery scales.

Oak leaf hydrangea; the conspicuous white flowers are really sterile.

Oak leaf hydrangea occurs naturally in GA only in the western counties, as well as further west to TX and TN, where it is associated with circumneutral soils. The showy flowers are actually sterile; much smaller fertile flowers are held in tight clusters amid the showier sterile ones.

Spicebush with two red fruits -- so this plant must be ___.
Fill in the blank with staminate or pistilate.

Spicebush stimulated a lot of discussion about the sexual arrangements of plants. Most people know that a "typical" flower has two sexual parts: the stamens that produce pollen and the pistil that produces the seeds. These are called "perfect" or “bisexual” flowers. But that is not the only possible arrangement of sexual parts. Some plants have flowers that lack one or the other of the sexual parts. In some species these imperfect flowers are found on the same plant, a condition called "monoecious," literally “one house.” Other plant species have only one type of flower on each individual, a condition called "dioecious" i.e. two houses. The consequence of this condition is that not every plant will be able to produce seeds. The individuals with only staminate flowers can never produce seeds because they lack the pistil, the female plant reproductive organ. The plants that have only pistillate flowers can potentially produce seeds, but only if there is a staminate plant close enough to transmit pollen to the pistil.

Another point also needs to be reviewed. The pistil is composed of three parts: 1) the ovary, 2) the style, and 3) the stigma. The ovary contains the egg cells that will develop into seeds if fertilized. The stigma is the site where pollen is received; it is connected to the ovary by the style. When compatible pollen is transferred to the stigma, it starts to grow a tube that extends down the style toward the ovary. When the pollen tube reaches the ovary it releases the sperm cells it contains and they fertilize the nearby egg. The fertilized egg develops into a seed and the seed is enclosed in a fruit that is formed by the ovary. Note: not only can a staminate plant never produce seeds, it will never produce any fruit, either.

Now back to the Spicebush. It is a dioecious plant, a species that has its male and female flowers on separate plants. In the DNFG, there are two spicebush plants growing closely together; one is male and the other female. Only the female plant has the red berries. We saw both plants flowering this year in early March. Click here and scroll down to see what the staminate and pistillate flowers looked like.

Highbush blueberry is a native blueberry; the underside of its leaves are pale with a slight waxy coating. Highbush blueberry differs from the Mayberry plant which has green stems and bright green leaves.

A thicket of Dog hobble

Dog hobble was seen next to the artificial stream in the DNFG, the same habitat where you'll find it in the mountains and the coastal plain. It is in the blueberry family and shows it with a flower that is urn-shaped, just like its blueberry cousins.

Fruits of the Painted buckeye

Painted buckeye with fruit and opposite, palmately compound leaves. Flowers in early April, leafs out early and drops them early. Twigs are also opposite.

Fruit of the Mountain silverbell; the ridges are the "wings."

Silverbell -- Linda says: "There are 3 species of Silverbell in GA: Little Silverbell (Halesia carolina), which has 4-winged fruits; Mountain Silverbell (H. tetraptera), which also has 4-winged fruits; amd Two-winged Silverbell (H. diptera), which has 2-winged fruit. The two species of 4-winged Silverbells can be distinguished by the shape of the fruit. Mountain Silverbell is ellipsoid in general outline and the wings are broad. This is the species we saw in DNFG today. It is most common in the mountains and the piedmont. Little Silverbell fruits are strongly narrowed to the base and has narrow wings. It is most common in the Coastal Plain. Two-winged Silverbell is uncommon in GA."

Parsely-leaved hawthorn

Parsley-leaved hawthorn is unique among the many difficult-to-identify Hawthorns in having leaves that resemble parsley.

Silky dogwood was found growing through the fence along the road. Its leaves have five or more veins on each side of the main vein, which distinguishes it from a similar wetland shrub, Swamp Dogwood (Cornus stricta), which has 3-4 veins on each side of the main vein.

Arrowshaped micrathena, an orb weaving spider

A spider egg case

Spiders: we found a small, circular egg case attached to a leaf by silken guy ropes. We don't really know what it is but it's similar to egg cases produced by spiders. We also found a bizarrely shaped spider on its orb web -- an Arrowshaped Micrathena. These are commonly seen in wooded area in late summer and fall.

SUMMARY OF OBSERVED SPECIES:

Common Name	Scientific Name
Piedmont or Pinxter azalea	Rhododendron canescens
Orb-weaver spider	Not identified
Japanese camellia	Camellia japonica
Bottlebrush buckeye	Aesculus parviflora
American witch hazel	Hamamelis virginiana
Sweet pepperbush	Clethra alnifolia
Sasanqua camellia	Camellia sasanqua
Small anise tree	Illicium parviflorum
Pipestem	Agarista populifolia
Spider egg sac on pipestem	Not identified
American beautyberry	Callicarpa americana
Dwarf pawpaw	Asimina parviflora
Yaupon holly	Ilex vomitoria
Cranefly orchid	Tipularia discolor
Georgia hackberry	Celtis tenuifolia
Black cohosh	Actaea racemosa
Ovate catchfly	Silene ovata
Alabama rhododendron	Rhododendron alabamense
Woodland spider lily	Hymenocallis occidentalis
Plum-leaf azalea	Rhododendron prunifolium
Leatherwood	Dirca palustris
Devil’s walking stick	Aralia spinosa
Alabama croton	Croton alabamensis
Tulip poplar	Liriodendron tulipifera
Deciduous holly	Ilex laevigata
Oak leaf hydrangea	Hydrangea quercifolia
Arrowshaped micrathena	Micrathena sagittata
Spicebush	Lindera benzoin
Highbush blueberry	Vaccinium corymbosum
Doghobble	Leucothoe sp.
Painted buckeye	Aesculus sylvatica
Four-winged silverbell	Halesia tetraptera
Parsley leaf hawthorn	Crataegus marshallii
Silky dogwood	Cornus amomum
Joe Pye weed	Eutrochium purpureum