Today's Ramble was led by Dale Hoyt.
Here's the link to Don's Facebook album from today's Ramble. (All the photos in this
post are compliments of Don.)
Today's post was written by Dale Hoyt.
Twenty-nine Ramblers today.
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| Red-bellied snake |
In lieu of a reading this morning we passed
around a small Red-bellied snake, brought in by Jeff. He found the snake in
a decaying pine stump and we have seen one here in the Garden on a ramble a few years ago. Red-bellied snakes are secretive, foraging in the leaf litter and eating mostly slugs and probably other small invertebrates. They don't get very large – just a little more than a foot in length.
a decaying pine stump and we have seen one here in the Garden on a ramble a few years ago. Red-bellied snakes are secretive, foraging in the leaf litter and eating mostly slugs and probably other small invertebrates. They don't get very large – just a little more than a foot in length.
Announcement:
Next Wednesday, Mike Wharton will lead a walk
around the managed forest area at Sandy Creek Nature Center. Here's the link to our Announcements page for more information about events of interest to Nature Ramblers.
Everyone joined in wishing Emily a Happy Birthday
by singing "Happy Birthday."
Today's Route: We went directly to the Dunson Native Flora
Garden (DNFG) via the mulched path, then to the bottom of the DNFG and returned
back to the parking area.
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| Frost-killed Ginkgo leaves & male cones |
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| Replacement leaves are appearing |
Frosty consequences: The exceptionally warm
weather we had this year lulled some plants into a sense of security and they flowered
or leafed out way early. Then March delivered a few nights with temperatures in
the twenties and 80% of the Georgia blueberry crop was lost. 85% of the South
Carolina peach crop was also lost. When flowers are destroyed by low
temperature that is the end of the road – no flowers, no fruit or seeds. Unlike
the flowers leaves that are damaged or destroyed by frost can be replaced for a
second try. The Ginkgos by the Shade
Garden Arbor are a good example. Their early-emerging leaves were killed by the
March frosts and are now being replaced by the growth of new leaves, leaves
that would not normally have appeared. Our native trees apparently know better.
Unlike the Japanese Maples and the Ginkgos they weren't fooled by the warmth of
February. Most have kept their buds tightly closed and only a few are now
beginning to leaf out. Our native Red Maples and Winged Elms managed to flower
and set seed before the frost hit, but timing is everything – last year many early
flowering Red Maples lost their seeds to an earlier frost.
Use Don's photo albums for a complete list of plants. Many of the plants we saw today were also present
last week, so you can consult last week's post and Don's facebook albums to see
them. I'm going to concentrate today's post on the new faces in the DNFG and
elaborate on some other topics suggested by questions Ramblers asked.
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| Newly emerged Red Maple leaves starting to expand |
Bud break: The leaves of our native trees are beginning to
emerge from their winter buds. Those of the Buckeyes have been out for about
two weeks, at least. Other trees are a little later. Today we noticed opening
buds on American Beech, Hophornbeam and one of the Maples (probably Red Maple).
The bud scales cover the developing leaf or shoot and protect it during winter.
In the spring the bud scales fall off and the leaf expands. The remarkable
thing about this process is that the leaf doesn't increase in size like we do
(by increasing our number of cells) but by increasing the size of its cells. As
the bud opens water flows up from the roots and into the leaves where it enters
each cell. The influx of water puts pressure on the cell wall, causing it to
expand. Like a self-inflating origami figure the leaves spring into the size
and shape that was already determined the previous fall when the bud formed.
The lateral buds usually produce a single leaf or flower or, perhaps, both. But
the terminal bud, the bud at the end of a twig, will contain a shoot with
several leaves. It will be responsible for this year's increase in the length
of the twig and may add many inches of rapid growth to the twig, all
principally due to increase in cell size. Last spring one twig on a White Oak in
our yard grew nine inches in just a few weeks!
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| Carolina Spring Beauty with open blossoms |
Carolina Spring Beauty surprised us by
having a few flowers open. Usually they remain closed on cool, cloudy days. This
species is interesting because it has a specialist pollinator, a small solitary
bee called, aptly enough, the Spring Beauty bee. It exclusively visits Spring
Beauty flowers, collecting pollen to feed its larvae. This bee is totally
dependent on Spring Beauty. If there is no flower the bee cannot produce
offspring. But the flower can survive without the bee, as it can be pollinated
by other insect visitors. A few years ago, in connection with a privet removal
project in the Garden, bee species abundance was determined in areas with and
without privet. That study found a small number (3) of Spring Beauty bees. To
my knowledge the only place in the Garden where Spring Beauty can be found is
in the DNFG.
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| Christmas fern fiddleheads |
Ferns are making their appearance in the DNFG and today
we saw the fiddleheads of Christmas fern.
This fern is evergreen, but the fronds that persist through the winter are
pretty ratty looking by now and can be seen in the leaf litter around the
cluster of fresh new fronds. The frond is composed of numerous small leaflets
(called pinnae in fern-speak). Each of these is shaped like a boot or Christmas
stocking.
The fiddlehead
term may be obvious – it's an allusion to the shape of the head of a violin.
When the fronds (leaves) of some ferns emerge from the soil they are rolled up
into a flat coil and gradually unroll as they extend upward. Another name for
the coiled structure is a crozier or crosier, an allusion to the ceremonial
staff of a bishop, which has a hook at the end. (A botanical term to describe
this is "circinate," meaning rolled up with the tip in the center.)
Are fiddleheads edible? Several
ramblers wanted to know if or had heard that fiddleheads can be eaten. In the
northeastern US they are apparently a spring delicacy. The fiddleheads of
Ostrich fern, a fern that is not native to Georgia, can be found seasonally in
New England markets and grocery stores. All ferns should be cooked properly as
they contain chemicals that are destroyed by heat. In general, ferns are
heavily defended against being eaten by chemicals in their tissues. Bracken
fern, for example, contains a known carcinogen and many ferns have an enzyme
that destroys thiamine (vitamin B12). Ferns seldom show any signs of having
been eaten, either by insects or deer. This fact alone should give you pause
before eating something that other animals don't.
Ferns reproduce by spores instead of seeds. A spore is a single cell whereas a seed
contains an embryonic plant and nutritive tissues that support its development.
In some ferns spores are produced on the undersurface of the fronds, while
others have entire fronds dedicated to producing spores and in still others
only a portion of the frond produces spores. The spore-producing fronds are
called the fertile fronds and those
that do not produce spores are called sterile
fronds. We saw three ferns today that have separate fertile fronds:
Rattlesnake fern, Cinnamon fern and Sensitive fern. The
single example of the Cinnamon fern has a tall fertile frond
that carries numerous cinnamon-colored sporangia (the spore-producing structures).
The Sensitive fern has not yet
developed its fertile frond – it's on a stalk that is separate from the sterile
frond.
The Rattlesnake fern fertile
frond is just starting the emerge. When mature it will project above the other
sterile fronds.
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| Cinnamon fern; brown fertile frond, green sterile fronds |
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| Sensitive fern sterile fronds |
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| Rattlesnake fern; fertile frond is erect, sterile fronds below |
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| Southern Lady fern; usually the rachis is red in color |
Southern Lady fern
usually has reddish colored rachis (the stalk that the leaflets are attached
to), but we also saw a group that had a green rachis.
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| Brown Panopoda moth with crumpled wings |
Resting on one of the Southern Lady ferns, was a Brown Panopoda moth with a crumpled
wing. When butterflies and moths emerge from their pupal stage their wings are
tiny pads. The insect pumps blood into the wing pads to inflate them. They
gradually expand to their full size and then must harden before the insect can
fly. If anything interferes with this process, like bumping into a twig, rock
or other object, the wing can be damaged and fail to expand properly.
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| May-apple flower bud |
May-apples are usually found in colonies of many
umbrella-like plants, but in the DNFG only a few plants are found growing
together this year. When a May-apple has sufficient energy it produces a pair of leaves
and at the juncture of two leaves a single flower. We saw two such plants
today, both with developing flower buds that will open later this spring. All
parts of the May-apple are poisonous; in fact, one of the compounds isolated
from the plant is used in cancer chemotherapy. The only edible portion of the
plant is the fruit and only when it is ripe. The only know disperser of May
apple seeds is the Box turtle, so apparently they know when the fruit is ripe.
After consuming the fruit they wander away and defecate the seeds elsewhere.
Twice as many seeds germinate after passing through the Box turtle gut as
compared to those that do not take that voyage.
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| Spanish bluebells; They're baaack! |
No ramble would be complete without encountering an
invasive plant of some sort. Today was no exception. Growing near the Spring
Beauties we found several Spanish bluebells, hyacinth-like flowers that spread
like mad. Three years ago, in early April, 2014, several ramblers and other
people spent 21 people hours pulling Spanish bluebells from this same part of
the DNFG.
Early Meadow Rue is
about finished blooming. Like Spicebush, it is a dioecious plant, meaning that the flowers on a single plant are of
one sex only, either male or female. This condition is like that of humans and
most other mammals – the sexes occur in separate individuals. Plants have a
bewildering variety of sexual combinations, in part because they can have
multiple sex organs, the flowers, on a single individual. Each flower can have
one or both types of sex organs and these can be found in almost every
conceivable combination. Focusing on the dioecious condition only, makes
outcrossing mandatory. A female dioecious plant can only make seeds if it is
fertilized by a pollen grain from a completely different and male plant.
In the opposite, monoecious, condition every plant
has flowers that are either perfect (produce both pollen and ovules) or flowers
that either produce pollen only or ovules only (different sex flowers on the
same plant). In either of these monoecious conditions it is possible for a
plant to self-fertilise.
Why is self-fertilization undesirable? Sexually reproducing
organisms (plant or animal) usually get one set of genetic material from their
female parent and another set from their male parent. These two sets of genes
are usually not the same (e.g., one parent might contribute a gene for blue
eyes and the other a gene for brown eyes). Some of these genetic differences
may be disadvantageous, but recessive. (Recessive means not expressed as long
as one member of the gene pair is not disadvantageous. For example, Queen
Victoria had a gene for hemophilia, but also had a normal, non-hemophilia gene,
so she did not suffer from hemophilia.) The problem with self-fertilization is
that the chances of producing seeds or children, with a disadvantageous pair of
genes is greatly elevated (it is 25%). That 25% figure assumes that each parent
has only one "bad" gene and the offspring gets a bad gene from both
parents. But living organisms have many other "bad" genes so the
chances of having offspring with one or more bad gene pairs goes way up with
self-fertilization. Any trait or feature that reduces the likelihood of
self-fertilization would then have an immediate advantage. And, for that
reason, we see in plants a whole range of characteristics that reduce the
chance of selfing. For example, many plants are self-incompatible, meaning that
if pollen from a flower lands on the stigma of the same flower or plant it will
not be able to fertilize any ovule of that flower. Becoming dioecious is
another way that guarantees the same thing as self-incompatibility. There are a
host of reproductive conditions that reduce the likelihood of selfing, but they
are too complex to explore in this short space. They are just not as extreme or
effective as self-incompatibility or dioeciousness.
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| Pale yellow trillium |
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| Lance-leaf trillium |
Georgia species of special concern: Several of the trilliums in the DNFG are
listed as Georgia species of special concern. Those we saw today are
Chattahoochee trillium, Pale Yellow trillium and Lance-leaf trillium, the
latter two making their first appearance today. (A species is considered as of special
concern if, although it is not endangered or threatened, it is extremely
uncommon in Georgia, or has unique or highly specific habitat requirements and deserves
careful monitoring of its status.)
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| Red buckeye |
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| Columbine |
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| Celandine (Wood) poppy |
Calciphilic plants (Calciphiles) are plants that do best when grown in soils
with high calcium content. (These are sometimes known as "sweet"
soils, i.e., soils with higher pH (7-8) than "sour" soils, soils with
acidic pH (<7). Such soils typically overlay bedrock like limestone. In
Georgia such soils are found in the NW part of the state and in various
localities in the coastal plain. Calciphiles we saw today: Allegheny spurge, Red buckeye, Celandine poppy, Virginia bluebells, Columbine,
and Lance-leaf trillium.
SUMMARY OF OBSERVED SPECIES:
Red-bellied snake
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Storeria occipitomaculata
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Ginkgo
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Ginkgo biloba
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Eastern hop-hornbeam
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Ostrya virginiana
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Unidentified maple
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Acer sp.
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Rattlesnake fern
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Botrypus virginianus
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Pale yellow trillium
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Trillium discolor
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Woodland phlox
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Phlox divaricata
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Dwarf crested iris
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Iris cristata
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Perfoliate bellwort
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Uvularia perfoliata
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Unidentified sedge
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Carex sp.
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Rue anemone
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Thalicatrum thalictroides
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Painted buckeye
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Aesculus sylvatica
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Chattahoochee trillium
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Trillium decipiens
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Golden ragwort
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Packera aurea
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Allegheny spurge
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Pachysandra procumbens
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Green-and-gold
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Chrysogonum virginianum
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Southern lady fern
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Athyrium filix-femina asplenoides
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Brown panopoda moth
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Panopoda carneicosta
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Spanish bluebells
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Hyacinthoides hispanica
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Carolina spring beauty
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Claytonia caroliniana
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Early meadow rue
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Thalictrum dioicum
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Georgia dwarf trillium
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Trillium georgianum
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Three-parted violet
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Viola tripartita
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Sensitive fern
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Onoclea sensibilis
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Jack-in-the-pulpits
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Arisaema triphyllum
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Christmas fern
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Polystichum acrostichoides
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Celandine wood poppy
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Stylophorum diphyllum
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Mayapple
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Podophyllum peltatum
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Atamasco lily
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Zephyranthes atamasca
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Cinnamon fern
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Osmunda cinnamomea
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Virginia bluebells
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Mertensia virginica
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Columbine
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Aquilegia canadensis
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Lance-leaf trillium
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Trillium lancifolium
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Spicebush
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Lindera benzoin
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Oak-leaf hydrangea
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Hydrangea quercifolia
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Japanese maple
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Acer palmatum
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