Ramble Report August 24 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 .

30 Ramblers met today.

Announcements:

1) Don announced more details about his Coweeta Hydrologic Laboratory trip for Nature Ramblers. Visit our Announcements page for all the details.

2) Katherine brought a hummingbird feeder to give away.

3) Dale handed out new name tags for most of those present. You are responsible for this name tag. Save it and bring it with you to each Ramble. (Keep it in your car so you don't forget it.)

No reading today

Late addition (8/27): Cure yourself of tree blindness. 

Today's Route:   We left the entrance plaza at the Visitor Center and made our way down the paved path to the International Garden, passing by the American South section, then taking a left onto the path to the South America section. Here we took a path out to the Pitcher Plant Bog. Leaving the bog, we made our way through the Native American Southeastern Tribes and Herb and Physic Gardens, before retiring to the Cafe Botanica.

Show and Tell:  Dale brought two mystery plants and several Southern Red Oak limb tips to show.

Ragweed infloresence

Ragweed leaf

The first mystery plant was Ragweed, identified by its raggedy leaves and nondescript, green flowers in slender spikes. The plant is monoecious (“one house”), with flowers of both sexes in the same spike-like flower cluster. The female flowers are at the bottom of the flower cluster and the male flowers are at the top. The light-weight pollen produced by the male flowers can be carried for hundreds of miles in the wind. Ragweed pollen is the culprit behind many late summer and fall allergy attacks. The allergen is actually a substance on the surface of the pollen grains. The plant is self-sterile, meaning that pollen from the male flowers are incompatible with female flowers of the same plant, so their close proximity in the same flower cluster does not result in self-pollination.

Spanish Needles flower heads

Spanish Needles bipinnate leaf

Dale compared Ragweed with a second mystery plant whose leaves look suspiciously like Ragweed’s but the flowers are very different. Its “flowers” are actually composite flower heads, with tiny, dark yellow disk flowers in the center surrounded by a few yellow ray flowers that look like petals. The mystery lay with the stems – which are square – and the leaves – which are opposite. Doesn’t that make the plant a mint?  Ah, would that plants followed our rules! No, this is Spanish Needles, a member of the composite, or Aster, family. Several plant families have adopted the Mint family model of square stems and opposite leaves, such as some species in the verbena and snapdragon families. Spanish Needles is known to most of us in the form of its annoying seeds that are pointed and barbed such that they easily work their way into and through socks, sticking one in the ankles.

Southern Red Oak; last year's acorns still developing; will mature this fall.

Southern Red Oak; this year's acorns; will mature and fall next year.

Dale also brought along branches from a Southern Red Oak to demonstrate the two-year acorn-maturing cycle for oaks in the red oak subgenus. The branches were long enough to have growth from last year (2016) as well as from this year’s (2017) growing season. The acorns on the newer growth are very small and bud-like. Further up the branch, the acorns on last year’s growth were larger and more developed, with cups (or caps) and nuts clearly distinguishable. These acorns will complete their development this fall, to the delight of deer, squirrels, chipmunks, and other wildlife.

Oaks in the white oak subgenus have acorns that mature in one year so you would not find both immature and mature acorns on the same branch. Interestingly, acorns in the white oak group are tastier than red oak’s. Spending fewer months exposed to nut-eating animals, they have less of the bitter-tasting tannin and were the acorns preferred for eating by Native Americans. Apparently, animals aren’t so picky because deer, squirrels, etc., relish all the acorns equally. Another way to distinguish between trees in the red oak group and trees in the white oak group is the leaves: red oak leaves have pointed lobes tipped with tiny bristles; white oak leaves have rounded lobes without a bristle.

Some common Georgia red oaks:  Northern Red Oak, Southern Red Oak, Scarlet Oak, Water Oak, Black Oak.

Some common Georgia white oaks:  White Oak, Chestnut Oak, Swamp Chestnut Oak, Live Oak (Georgia’s state tree).

Today's focus:  Plants in the pitcher plant bog and other things in the International Garden

American South Section:

We saw what we first thought were spadefoot frogs but, according to Jeff, they are either American or Fowler's toads.

We saw several fungi, including Japanese parasols, which occur in North America, Japan, and Europe, and small puffballs.

Narrow-Leaved Ironweed is in flower in the American South section. In the same genus and with similar flower heads as the Tall Ironweed that grows so robustly in the Garden’s powerline right-of-way, these narrow-leaved plants are adapted to life in the dry, extremely well drained soils of Georgia’s Coastal Plain sandhills. Plants with narrow leaves will lose less moisture because the small amount of leaf surface reduces transpiration (water loss). Plus, the leaf doesn’t heat up as much in south Georgia’s hot summers. Typically, narrow leaves are also rolled under along their edges, partially covering and protecting a line of stomates, or pores, that open to let in carbon dioxide for photosynthesis. The plant must take in CO₂ but runs the risk of drying out when the pores are open. Most dry-land species have “figured out” how to balance the need for CO₂ with the need to conserve water. Other such adaptations include waxy or hairy leaf surfaces and leaves held at a slant to the sun’s rays.

Obedient plant

In the same bed is a large patch of Obedient Plants. It's named Obedient Plant because you can push the flower to one side and it will stay “obediently” where pushed. It's a native mint family species, with square stems, opposite leaves, and two-lipped flowers. As mentioned earlier, other plant families may have square stems and opposite leaves, but the mint family also has distinctive tubular flowers with a downturned lower lip and an upturned or projecting  upper lip. The lower lip usually has a pattern of contrastingly colored lines or dots that direct insects into the center of the flower where nectar or pollen or both are available. These nectar guides or “runway lights” may be even more elaborate than humans can see. Bees can see colors in the ultraviolet end of the spectrum, and flowers often have patterns visible to them but not to us. This website has images of flowers under both human-visible light and bee-visible UV light: Flowers in Ultraviolet (www.naturfotograf.com).

Spanish America Section:

Turk's Cap Hibiscus

Linda pointed out the vivid red flowers of Turk's Cap Hibiscus, a member of the Hibiscus or Mallow family. Although the partially closed flowers are different from the wide-open flowers of most hibiscus, this species has the typical Mallow family arrangement of stamens and pistil. The stamens are fused into a hollow tube that surrounds the style, and the “sticky stigmas” protrude from the top of the tube. In this plant the stamens and stigmas extend well beyond the petals. Another typical hibiscus feature found on this plant is the whorl of bracts surrounding the base of the flower.

Camphor Weed

Some folks quickly picked up the smell of a Camphor Weed plant, a member of the Aster family with pale pink or lavender flower heads and strongly smelling vegetation. Smell is a subjective thing – most folks find the odor offensive, likening it to the smell of a cat litter box, and others sort of like the way it smells. None of the ramblers seemed to think it smelled like camphor. Although smelly plant compounds evolved to deter herbivores, strong-smelling plants often turn up in traditional, non-western medicine and attract the attention of scientists who are looking for medicinal uses of plants. Members of this genus, Pluchea, are packed with compounds that have been investigated for anti-bacterial, anti-malarial, or even anti-cancer activity.

The needle-like point of a Soft Rush leaf

Soft Rush fuit cluster

Crossing the artificial stream that bisects the International Garden, we stopped to admire another very effective plant defense: the sharply pointed tips Soft Rush stems. This also provided an opportunity to review what we know about the stems of three groups of grass-like plants: “sedges have edges, rushes are round, and grasses are hollow all the way to the ground.” Soft Rush stems are indeed round in cross-section and not at all hollow–they are filled with a spongy pith that allows oxygen and carbon dioxide to flow within the stems, an important feature in plants that inhabit the low-oxygen soils found in wetlands.

Pitcher Plant Bog Garden:

Late summer is a good time to visit bogs, especially in the Coastal Plain. Linda recommended that folks visit some of the spectacular bogs found in the Florida panhandle, such as those at Blackwater River State Forest and Apalachicola National Forest. Sunflowers, Blazing Stars, and Meadow-beauties are all at their prime this time of year, up until frost.

Pitcher plant flower(L); White-top Pitchers (R)

Pitcher Plants flower in the spring and have lost their petals by now, but fascinating aspects of their floral anatomy are still visible in the spent flowers nodding at the top of tall stalks. The most obvious feature is the upside-down “umbrella” that tops the pistil. In most flowers, stigmas are fairly inconspicuous structures held at the top of the style, but in pitcherplants the whole umbrella is an expanded style. Pollen deposited on the tips of the umbrella’s “ribs” can find its way to the ovary and effect fertilization. The umbrella combined with the drooping petals also ensure that insects are trapped long enough to bumble around among the stamens, picking up pollen which they may carry to the next plant.

Contents of a pitcher; insects in various states of decay. Yummy!

In a further affront to our olfactory organs, we split lengthwise a pitcher of a White-top Pitcher Plant to expose the insects which had been trapped and partially digested (cue: totally disgusting sights and smells!). Insects are attracted by sweet smelling nectar produced around the top rim of the pitcher and, if they fall in, are prevented from escaping by downward pointing hairs or slippery surfaces. Once trapped in the bottom of the pitcher, their bodies are digested by enzymes produced by bacteria that live in the pitcher, as well as those produced by the plant. In fact, pitcherplant pitchers support a suite of creatures that depend on them for shelter and food, including some that are found nowhere else but those pitchers, a wonderful example of symbiosis. Both plant and bacteria depend on this insect soup for nutrients such as nitrogen and phosphorus. Wetland soils, where pitcherplants live, are always low in available nitrogen, and pitcherplants, sundews, butterworts, and bladderworts make up for this lack with their carnivorous lifestyle. 

Virginia Meadow-beauty

Pale Meadow-beauty

Other flowering bog species included Fragrant Flatsedge, Virginia Meadow-beauty, Pale Meadow-beauty, Yellow-eyed Grass, Seed-box, Round-leaved Thoroughwort, Dwarf St. John's Wort, and Poor Joe. Of special interest were the stamens in the meadow-beauty flowers, with their hinged, boat-shaped anthers. The anthers have tiny pores at their tips and are buzz-pollinated by bumblebees. The fruits that result from pollination and fertilization look like tiny, wooden vases and persist on the dried plants through the winter. There are nine species of Meadow-beauty in Georgia, but the only common one in the Piedmont is Maryland Meadow-beauty, aka Pale Meadow Beauty, which has white or very pale pink flowers. 

Flower stalks of Yellow-eyed Grass (not really a grass!)

Single flower of Yellow-eyed Grass

Tall stalks rising from a clump of Yellow-eyed Grass caught our eye. At the top of each Yellow-eyed Grass stalk there is a cone-like structure composed of many brown, overlapping scales. Each day, a yellow, three-petaled flower emerges from under a scale for a few hours then withers away. (The time and duration of flowering differs among species.) We saw both withered and fresh flowers. Katherine noted that there are many species of yellow-eyed grass, up to 20 in Georgia. Many are rare due to the loss of their bog and wet prairie habitats due to draining and conversion to pine plantations. Yellow-eyed Grasses vary in size from a few inches to several feet tall. Their flowers are pollinated by bees and flies but will also self-pollinate if insects don’t show up during their brief flowering period. 

A large Ogeechee Lime tree shades the eastern edge of the Bog Garden. Not at all related to the citrus family, Ogeechee Lime is actually a species of black gum. (Another of these trees is planted in the wet area at the western edge of the Dunson Native Flora Garden.) Ogeechee Lime is named for Georgia’s Ogeechee River and for the tart juice in its green, somewhat lime-shaped fruits. There are two other wetland-inhabiting black gums in Georgia, Water Tupelo and Swamp Black Gum.

Path near Freedom Plaza:

We stopped at the Pawpaw patch and commented on the relative lack of fruit this year and how the crushed leaves smell like green bell peppers.

Winged Sumac stem showing lenticels (red spots)

Part of Winged Sumac leaf showing the "wings" between the leaflets

Nearby, is a Winged Sumac in full flower. Most conspicuous in late summer and fall when their dark red, conical fruiting clusters brighten the banks of highways, Winged Sumac also has a lot to offer a botanist with a good eye and a hand lens. Its small yellow-green flowers have 5 petals, the stems are hairy and peppered with tiny red lenticels, and the compound leaves have up to 21 pointed leaflets. The common name derives from the narrow wings of leaf tissue that connect each pair of leaflets with the pair above and below. This is a species that deserves to be in the horticultural trade: its leaves have beautiful red fall color, the flowers attract many types of insects, and the foliage supports a variety of caterpillars. The fuzzy red fruits are famous for their tart, lemony taste and are used by wild-food fanciers to make pink lemonade (many recipes are online). 

Freedom Plaza:

Freedom Plaza is a great place to see large plantings of several very showy natives in full flower: Joe Pye Weed, Eared Coneflower, and Spotted Bee Balm. All three of these species were swarming with bees, butterflies, and other insect pollinators. 

Eared Coneflower

Joe Pye Weed (with Tiger Swallowtail)

Spotted Bee Balm

Joe Pye Weed greeted us as we arrived at the plaza, its huge, pinkish-purple inflorescences crowned with both male and female yellow tiger swallowtail butterflies.

Just past the Joe Pye Weed is a stand of the tall, rare Eared Coneflowers. Typically found growing on sand bars and stream banks, they appear to be thriving in the dry soil at the base of the Freedom Plaza wall. It’s often the case that “wetland plants” will thrive in upland garden settings, and in nature are confined to wetlands because there are fewer plant competitors. 

Butterfly Weed

We saw a couple of small plants of Butterfly Weed, a member of the milkweed genus, sporting some late-flowering orange blossoms. Milkweeds are essential to the life cycle of Monarch butterflies, its leaves exclusively providing food to the Monarch larvae (caterpillars). The leaves are full of a milky latex that contain toxic glycosides that the caterpillars take up and later pass to the adult butterfly during metamorphosis. Birds quickly learn to leave these adults alone because the toxins will make them sick or even kill them. Ironically, the one milkweed species that lacks the toxic latex is the one named Butterfly Weed. Even so, it is still used by the Monarch as a host plant for its larvae. The adult Monarchs that result from these caterpillars are not particularly toxic but are avoided by birds who have learned to avoid Monarchs in general.

Herb and Physic Garden:

Clearwing Moth nectaring on Cleome (note the proboscis inserted in the flower)

A Clearwing Moth was busy nectaring on the flowers of Cleome, or Spider Plant, a showy plant native to southern South America. Meanwhile, a Ruby-throated Hummingbird zoomed around, seeming impatient while the moth and the ramblers had their fill.

SUMMARY OF OBSERVED SPECIES:

Japanese parasol mushroom	Coprinus sp.
Narrow-leaved Ironweed	Vernonia angustifolia
Obedient Plant	Physostegia virginiana
Pawpaw tree	Asimina triloba
Turk's cap Hibiscus	Malvaviscus arboreus
Camphor weed	Pluchea camphorata
Soft Rush	Juncus effusus
White-topped Pitcher Plant	Sarracenia leucophylla
Hybrid pitcher plant	"Scarlet Belle"
Flatsedge	Cyperus sp.
Marianna or Pale Meadow Beauty	Rhexia mariana
Virginia Meadow Beauty	Rhexia virginica
Yelloweyed Grass	Xyris sp.
Seedbox	Ludwiga alternifolia
Dwarf St. John's Wort	Hypericum mutilum
Round-leaved Thoroughwort	Eupatorium rotundifolium
Ogeechee Lime	Nyssa ogeche
Poor Joe	Diodella teres
Blue Curls	Trichostema dichotomum
Winged Sumac	Rhus copallinum
Joe Pye Weed	Eutrochium fistulosum
Eared Coneflower	Rudbeckia auriculata
Spotted Beebalm	Monarda punctata
Buttefly Weed	Asclepias tuberosa
Onion	Allium sp.
Clearwing moth	Hemaris thysbe
Cleome, Spider Plant	Cleome hassleriana