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:
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.)
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.
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| Ragweed infloresence |
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| Ragweed leaf |
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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.
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| Spanish Needles flower heads |
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| Spanish Needles bipinnate leaf |
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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.
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| Southern Red Oak; last year's acorns still developing; will mature this fall. |
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| 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.
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| Obedient plant |
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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:
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| 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.
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| Camphor Weed |
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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.
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| The needle-like point of a Soft Rush leaf |
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| Soft Rush fuit cluster |
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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.
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| Pitcher plant flower(L); White-top Pitchers (R) |
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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.
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| 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.
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| Virginia Meadow-beauty |
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| Pale Meadow-beauty |
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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.
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| Flower stalks of Yellow-eyed Grass (not really a grass!) |
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| Single flower of Yellow-eyed Grass |
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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.
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| Winged Sumac stem showing lenticels (red spots) |
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| 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.
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| Eared Coneflower | |
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| Joe Pye Weed (with Tiger Swallowtail) |
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| Spotted Bee Balm |
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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.
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| Butterfly Weed |
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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:
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| 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
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Coprinus sp.
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Narrow-leaved
Ironweed
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Vernonia
angustifolia
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Obedient Plant
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Physostegia
virginiana
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Pawpaw tree
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Asimina triloba
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Turk's cap Hibiscus
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Malvaviscus
arboreus
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Camphor weed
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Pluchea
camphorata
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Soft Rush
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Juncus
effusus
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White-topped
Pitcher Plant
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Sarracenia
leucophylla
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Hybrid pitcher
plant
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"Scarlet
Belle"
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Flatsedge
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Cyperus sp.
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Marianna or
Pale Meadow Beauty
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Rhexia
mariana
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Virginia Meadow
Beauty
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Rhexia
virginica
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Yelloweyed
Grass
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Xyris sp.
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Seedbox
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Ludwiga
alternifolia
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Dwarf St.
John's Wort
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Hypericum
mutilum
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Round-leaved
Thoroughwort
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Eupatorium rotundifolium
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Ogeechee Lime
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Nyssa ogeche
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Poor Joe
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Diodella
teres
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Blue Curls
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Trichostema
dichotomum
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Winged Sumac
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Rhus
copallinum
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Joe Pye Weed
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Eutrochium fistulosum
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Eared
Coneflower
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Rudbeckia
auriculata
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Spotted Beebalm
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Monarda
punctata
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Buttefly Weed
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Asclepias
tuberosa
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Onion
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Allium sp.
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Clearwing moth
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Hemaris
thysbe
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Cleome, Spider
Plant
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Cleome
hassleriana
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