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 and Don
Hunter.
Twenty Ramblers met today.
Today's reading: Linda read Weather by Faith Shearin. You can find it here. Linda also thought that Ramblers would find this piece about the benefits of walking in nature of interest.
Announcements: Guided walk at Sandy Creek Nature Center
9:00 a.m., Wednesday, April 5. Mike
Wharton will be leading a walk through the areas recently cleared and planted
as part of the managed forest project at the center. (You can always check our Announcements page for the latest information about upcoming events.)
Today's route: On the other side of the parking area to
examine a Red Buckeye, the down the mulched path to the Dunson Native Flora
Garden. Then through the garden at our usual "speed of botany."
Frost damaged leaves and male cones of Ginkgo |
The WeatherSTEM unit at the Garden recorded a
hard freeze for three straight nights in March (15, 16 and 17); temperatures
reached 27°F for many
hours. The peach and blueberry crops in Georgia suffered severe damage and at
the Garden we see damage to some of the trees that had already leafed out: the
Ginkgos at the Arbor and one of the Japanese Maples. Strangely enough, the Red
Maples around the parking area didn't seem to be affected.
Red Maple samaras |
Red Maple
Linda passed around a Red Maple twig with
developing fruits. Long, slender red stalks dangled from the twig, each one
bearing a pair of maple fruits at its end. Linda remarked that the Red Maple
offers us something red in every season: the red flower in later winter and
early spring, the red leaf stalks in the summer and the leaf that turns red in
the fall.
If you're confused about what a maple fruit
is, remember that a fruit is what botanists call the thing that holds one or
more seeds of a flowering plant. The maple seed is enclosed at one end of a
wing-like structure and each flower can produce two seeds, each enclosed in
what looks like a wing. The whole thing, wing plus seed, is called a samara. When the fruit is ripe is drops
from the plant and whirligigs like a helicopter to the ground. If the wind is
blowing when the samara falls it will be carried a considerable distance from
the tree. In my neighborhood there is a Red Maple that flowered early in
February. It's fruits developed rapidly during the warm weather of that month
and were ripe just before last week's violent thunderstorm hit. The following
day the entire tree was stripped of fruit and I couldn't even find any on the
ground, either under the tree or nearby. The winds had been strong enough to
denude the tree and blow all its fruit away. The wing of the samara had done
its job.
Red Buckeye flower buds |
Painted Buckeye early flower buds |
Closeup of Red Buckeye flower These flowers are very attractive to hummingbirds. |
Red Buckeye
Across the parking area, near the
Administration building are several Red Buckeyes that have leafed out and also
have developed several clusters of red flower buds. Each flower is an elongate
cylinder that will open at the end, inviting the Ruby-throated hummingbird to
sip its nectar. To get the nectar the hummingbird inserts its bill deep enough
the reach the base of the flower and, in doing so, it picks up pollen from the
stamens inside the upper portion of the flower. When it visits another buckeye
flower the pollen will brush off on the stigma as the bill enters the flower.
The Red Buckeye is not native to this part of
Georgia. It is confined to the coastal plain. There is another, similar,
buckeye species that grows in the piedmont of Georgia and the Carolinas: the
Painted Buckeye. It has similar shaped flowers but they are yellow in color. In
natural areas of the Georgia piedmont you can find buckeyes with orange
flowers. These are hybrids between the Red and Painted Buckeye. Back in the
1980s a UGA graduate student and his professor (Claude DePamphilis and Dr.
Robert Wyatt) suggested that hummingbirds could carry pollen from Red Buckeyes
northward to the piedmont during their northward migration from Mexico and Central
America. Indeed, the dates of arrival of hummingbirds in the piedmont in those
years corresponded with the flowering times of the Red and Painted Buckeye. As
our climate warms it is possible this flow of pollen could be interrupted if
buckeye flowering and hummingbird migration become out of phase with each
other.
Ephemeral Spring Flora
In eastern North America there are a group of
species found in the herbaceous layer of vegetation that appear early in
spring, flowering, producing seed and then disappearing when the leaves appear
on the trees overhead and the canopy closes, reducing the sunlight they require
to reproduce. They persist underground from year to year as bulbs or other
types of underground organs: rhizomes, corms, etc. Examples of plants with this
lifestyle are hepaticas, bloodroot, trilliums, wild gingers, shooting stars, wood
poppy, dutchman's breeches, trout lilies, wild geranium, mayapples, etc.
Strictly speaking, to be a spring ephemeral all above ground evidence of their
presence must vanish after the canopy closes. But the leaves of some plants,
like bloodroot and hepatica, considered to be spring ephemerals, persist
throughout the summer and winter, dying only the following spring.
Another feature that many spring ephemerals
share is reliance on ants to disperse their seeds. These plants produce seeds
with a fatty, protein rich appendage called an elaiosome. (Some examples of
elaiosomes can be seen here.)
When foraging ants discover such a seed they grab the elaiosome with their
mandibles and carry it and the attached seed back to their nest. There other
ants cut off the elaiosome and feed it to the ant colony's developing brood. The
seed is picked up by the colonies sanitation ants and discarded at the colony's
refuse area along with other ant refuse and trash. Here the seeds find a rich
compost in which to germinate and produce a new plant. Depending on the ant
species, the seeds may be carried a considerable distance. In area surrounding
the Dunson garden you can find trilliums hundreds of feet from their likely
parents.
(For collectors of abstruse technical
terminology: the term for dispersal of seeds by ants is myrmecochory.)
Trilliums
There are trilliums blooming all over the
Dunson Garden today. Many species have been planted in the Dunson garden and over
the years they have a tendency to hybridize, so you will often find specimens
that don't look quite like what you expect. They also have been very successful
in dispersing themselves around the garden as well as some distance from where
they were originally planted. Following is a summary of trillium
characteristics needed for identification.
Erect or decumbent stems
Most of the trilliums in the Dunson garden
have stems that emerge straight up from the ground. In a few species the stems
grow along the ground surface for some distance before turning upward and
producing a flower.
Sessile vs. stalked flowers
The flowers of some trilliums seem to sit atop
the leaves. This condition is termed "sessile," which means directly
attached with a supporting stalk. The sessile flowered petals are straplike and
vary in color from yellow to dark brown or bronze. They sometimes have an
unpleasant odor which is thought to attract flies as pollinators. The trilliums
with sessile flowers are often called "toad shades." The petal bases
of some sessile-flowered trilliums are narrowed, allowing you to see other
flower structures (stamens) between them.
The trilliums that have a flower stalk between
the flower and the leaves are called stalked or "nodding," because in
many species the stalk bends downward so that the flower is carried below the
leaves.
Examples of sessile trilliums:
Chattahoochee trillium |
Chattahoochee
trillium is tall and the leaves have a silver stripe that runs down the
midvein. It is found only in a few counties along the Chattahoochee river.
Underwood's trillium looks like a short Chattahoochee trillium.
It has a more widespread distribution, occurring in Georgia, Florida and
Alabama.
Spotted trillium |
Spotted trillium
is tall, like the Chattahoochee, but lacks the silver stripe on the leaf midvein;
the leaves are mottled with different shades of green. The petals vary from
yellow to brown in color and are narrow at their base creating a gap through
which you can see the stamens.
Sweet Betsy trillium |
Sweet Betsy trillium is widespread in the mountains and
resembles the Chattahoochee trillium, but is shorter and lacks the silver stripe
along the midvein.
Decumbent trillium |
Trailing/Decumbent
trillium has stems that grow along the ground and then turn upward, bearing
the leaves and sessile flower just above the leaf litter.
Examples of stalked
trilliums:
Georgia Dwarf trillium |
Georgia Dwarf
trillium is a newly described species of nodding trillium. Originally it
was treated as a variety of the Dwarf trillium (Trillium pusillum var. georgiana) but is now recognized as a
distinct species.
Persistent trillium |
Persistent trillium is another small, white flowering trillium. Linda likes to call it Edna's
trillium, after Edna Garst, a long time resident of Athens who discovered it. Edna
and John Garst owned property near Toccoa, where they first noticed this
trillium growing. It didn't match any
known species of trillium and the Garsts brought it to Dr. Wilbur Duncan's
attention., who described it as a new species of trillium and named it the
persistent trillium. He named it
persistent trillium because the leaves remain well into the summer, long after
the leaves of other trilliums have disappeared. This
is an example of a trillium with the flower on a stalk and the flower is white,
unlike the maroon-colored flowers of the sessile species. It can be seen in the wild on the south rim
of the Tallulah Gorge
Dimpled Trout lily |
Trout lilies
There are two kinds of trout lilies in the
Dunson garden: American trout lily and Dimpled trout lily. The former is
represented by the large colony of mostly single-leaved plants massed at the
base of a tree. The colony is formed by stolons produced by each corm, a
bulb-like underground structure that persists from year to year. Only a small
fraction of the hundreds of individual plants in this colony produce flowers.
The rest bide their time, storing up starch in their corm until there is enough
to support the growth of two leaves and a flower.
The dimpled species does not form large colonies;
individual plants can be found elsewhere in the garden. This lack of colony
formation is because the dimpled trout lily corm does not produce stolons.
large colonies – is due to the presence or absence of stolon formation by the
underground corms. Each corm produces a single leaf until it stores enough
energy to flower, then it produces two leaves and a stalk with a single flower.
American trout lily: base of inner tepals with tiny lobes; end of fruit rounded without a depression.
Dimpled trout lily: inner tepals lack ears; end of fruit blunt with a small depression.
(Tepals are a term used in plants where the sepals and petals are indistinguishable. You can think of them as petals.)
(Tepals are a term used in plants where the sepals and petals are indistinguishable. You can think of them as petals.)
Golden Ragwort |
Green-and-Gold |
Golden ragwort and
Green-and-Gold are both in the Aster family. What appears to be a single
flower with yellow petals and a yellow disk is, in reality, a collection of florets
(tiny flowers). Each floret in the outermost circle of florets has a single,
yellow, strap-like petal. Each of the inner florets that make up the disk has a
tiny, trumpet shaped, yellow corolla (fused petals). With a hand lens you can
the anthers inside each corolla and, inside the circle of anthers, the tip of
the single pistil (the female part of the flower). Each of the florets, if
pollinated, will produce a single seed. In the case of the ragwort the seed
will have attached a packet of fuzz that allows the wind to carry the seed away
to another location. Green-and-Gold produces seed without any parachutes – it is
simply shed to the ground.
Early Meadow Rue; female flowers |
Early Meadow Rue; male flowers |
Early meadow rue is still
blooming. The sexes are on separate plants. Dioecious is the technical term for
this condition. Dioecious species cannot self-fertilize and avoid the problems
that arise from that type of inbreeding. The other side of the coin is that any
plant that is not near a member of the opposite sex will have trouble
reproducing.
Plants have a variety of ways in which the
sexes are distributed among individuals plants and flowers; here are some of
the arrangements:
Hermaphroditic: Each flower on a plant is perfect
(has both male and female parts).
Dioecious: Male and female flowers occur on different
plants.
Monoecious: Separate male and female flowers occur on
the same plant.
Andromonoecious: Male and
perfect flowers occur on the same plant.
Gynomonoecious: Female and perfect flowers occur on the same
plant.
Each of these arrangements seems to be
associated primarily with avoiding self-fertilization. Even in the
hermaphroditic case the male and female portions of the same flower often
mature at different times. So when the anther is shedding pollen the pistil of
the same flower is unreceptive. Since most animals are dioecious self fertilization
is not possible. Inbreeding can only occur when closely related individuals
mate.
Dwarf pawpaw flower |
Dwarf paw paw is currently flowering. The tiny flowers
resemble, except for size, those of the real Paw paw (Asimina triloba), which are dark maroon and are said to have a
yeasty odor. Flowers with this color are usually pollinated by flies and the
coloration is thought to resemble that of rotting flesh. Other types of flies,
like fungus flies, are attracted to the odor and might be effective
pollinators. Some people with paw paw patches hang road-killed animals from the
branches to increase fruit production.
Seersucker sedge
Linda pointed out a clump of seersucker
sedge, with it's distinctive pleated foliage. The name is a
reference to a fabric, seersucker, that was a staple of
Southern summer fashion before the advent of air conditioning. The dark purple male
flowers adorn the tips of the flower stalks, with the yellowish female flowers
found at intervals lower on the flower stalk beneath the male flower.
Violets
Three-parted Violet |
This Three-parted violet is growing
near the Persistent trillium in the Dunson garden and they have been found on
the Orange Trail in in previous years.
Violets are divided into two groups based on
whether or not the flower is born on a leafy stem. The Common blue violet
in your yard has a flower that is carried by a leafless stalk that grows
directly from the rhizome. Such violets are called acaulescent, meaning
stemless. In the other category of violets, caulescent or stemmed, the rhizome
sends up a leaf bearing stem that also bears one or more flowers. The
Three-parted violet is a stemmed or caulescent violet.
Violets have a nifty way of dispersing
their seeds. They combine the ballistic method with myrmecochory – that is,
they explosively expel their seeds, each of which carries an elaiosome. As the
seed capsule matures it splits into three parts, each with a few shiny
brown/black seeds attached down the middle. As the capsule structure dries out
each part pinches its contained seeds. The pinching pressure increases until
the seeds are explosively separated from the capsule wall. They can be ejected six
feet or more. This mechanism is like something you may have done with
watermelon seeds when you were a child. You gripped the seed between your thumb
and the first joint of your index finger and pinched has hard as you could. The
seed was slick and if you held it correctly it squirt out of your fist at
pretty high velocity. When I was a kid we held contests to see who could squirt
one the furthest. When we tired of that had watermelon seed wars, of course.
Columbine; nectar spurs are at the top. |
Columbine is an early spring perennial. It faces
downward and the long, red spurs produce nectar. Hummingbirds seek this out,
but to get it they must hover under the flower and tip their head up to insert
their bill into the spur.
Tulip tree flower bud Bud scales starting to fall off, exposing the bud inside. |
Tulip tree
The thunderstorm last week knocked down this flower bud from one of the
large tulip trees in the Garden. The flowers are usually so high up in the tree
you can't examine them. Your only chance for a closer look is violent winds or
squirrels – they seem to enjoy cutting off the flowers for unknown reasons.
Coral honeysuckle flowers, a hummingbird favorite! |
Coral Honeysuckle is a vine with red tubular
flowers that are very attractive to hummingbirds. This is a native,
non-invasive honeysuckle that can be planted without fear of destroying your
home environment.
For more pictures of flowers seen today visit Don Hunter's facebook album: Here's the link
Summary of Observed Species
Japanese maple
|
Acer palmatum
|
Black cohosh*
|
Actaea racemosa
|
Southern maidenhair fern
|
Adiantum capillus-veneris
|
Red buckeye**
|
Aesculus pavia
|
Painted buckeye**
|
Aesculus sylvatica
|
Sharp-lobed hepatica
|
Anemone acutiloba
|
Columbine
|
Aquilegia canadensis
|
Dwarf paw paw
|
Asimina parviflora
|
Cut-leaf toothwort
|
Cardamine concatenata
|
Seersucker sedge
|
Carex plantaginea
|
Green-and-gold
|
Chrysogonum virginianum
|
Carolina spring beauty
|
Claytonia caroliniana
|
Shooting stars
|
Dodecatheon meadia
|
American trout lily
|
Erythronium americanum
|
Dimpled trout lily
|
Erythronium umbilicatum
|
Ginkgo
|
Ginkgo biloba
|
Wild ginger**
|
Hexastylis arifolia
|
Largeflower heartleaf**
|
Hexastylis shuttleworthii
|
Dwarf crested iris
|
Iris cristata
|
Tulip tree
|
Liriodendron tulipifera
|
Coral honeysuckle
|
Lonicera sempervirens
|
Virginia bluebells
|
Mertenisa virginica
|
Allegheny spurge
|
Pachysandra procumbens
|
Golden ragwort
|
Packera aurea
|
Woodland phlox
|
Phlox divaricata
|
Mayapple*
|
Podophyllum peltatum
|
Celandine/wood poppy
|
Stylophorum diphyllum
|
Early meadow-rue
|
Thalictrum dioicum
|
Rue anemone
|
Thalictrum thalictroides
|
Sweet Betsy trillium
|
Trillium cuneatum
|
Chattahoochee trillium
|
Trillium decipiens
|
Trailing/decumbent trillium
|
Trillium decumbens
|
Georgia dwarf trillium
|
Trillium georgianum
|
Spotted trillium
|
Trillium maculatum
|
Edna's trillium
|
Trillium persistens
|
Underwood's trillium
|
Trillium underwoodii
|
Perfoliate bellwort
|
Uvularia perfoliata
|
Common blue violet
|
Viola sororia
|
Three-parted violet
|
Viola tripartita
|
*not flowering
|
|
**Flower buds
|