Saturday, April 1, 2017

Ramble Report March 30 2017



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.

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.

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.

Frost-killed Ginkgo leaves & male cones

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.

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!

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.

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
Cinnamon fern; brown fertile frond, green sterile fronds
single example of the Cinnamon fern has a tall fertile frond that carries numerous cinnamon-colored sporangia (the spore-producing structures).
Sensitive fern sterile fronds
The Sensitive fern has not yet developed its fertile frond – it's on a stalk that is separate from the sterile frond.
Rattlesnake fern; fertile frond is erect, sterile fronds below
The Rattlesnake fern fertile frond is just starting the emerge. When mature it will project above the other sterile fronds.
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.
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.

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.

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.

Pale yellow trillium

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.)

Red buckeye

Columbine

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
Storeria occipitomaculata
Ginkgo
Ginkgo biloba
Eastern hop-hornbeam
Ostrya virginiana
Unidentified maple
Acer sp.
Rattlesnake fern
Botrypus virginianus
Pale yellow trillium
Trillium discolor
Woodland phlox
Phlox divaricata
Dwarf crested iris
Iris cristata
Perfoliate bellwort
Uvularia perfoliata
Unidentified sedge
Carex sp.
Rue anemone
Thalicatrum thalictroides
Painted buckeye
Aesculus sylvatica
Chattahoochee trillium
Trillium decipiens
Golden ragwort
Packera aurea
Allegheny spurge
Pachysandra procumbens
Green-and-gold
Chrysogonum virginianum
Southern lady fern
Athyrium filix-femina asplenoides
Brown panopoda moth
Panopoda carneicosta  
Spanish bluebells
Hyacinthoides hispanica
Carolina spring beauty
Claytonia caroliniana
Early meadow rue
Thalictrum dioicum
Georgia dwarf trillium
Trillium georgianum
Three-parted violet
Viola tripartita
Sensitive fern
Onoclea sensibilis
Jack-in-the-pulpits
Arisaema triphyllum
Christmas fern
Polystichum acrostichoides
Celandine wood poppy
Stylophorum diphyllum
Mayapple
Podophyllum peltatum
Atamasco lily
Zephyranthes atamasca
Cinnamon fern
Osmunda cinnamomea
Virginia bluebells
Mertensia virginica
Columbine
Aquilegia canadensis
Lance-leaf trillium
Trillium lancifolium
Spicebush
Lindera benzoin
Oak-leaf hydrangea
Hydrangea quercifolia
Japanese maple
Acer palmatum

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