Ramble Report March 15 2018

Today's Ramble was led by Linda Chafin.

The photos in this post, except where noted, came from Don Hunter's Facebook album (here's the link).

Today's post was written by Linda Chafin.

27 Ramblers met today.

Today's reading: Bob Ambrose recited (from memory) Robert Frost's Nothing Gold Can Stay:

Nature's first green is gold,
Her hardest hue to hold.
Her early leaf's a flower;
But only so an hour.
Then leaf subsides to leaf,
So Eden sank to grief,
So dawn goes down to day
Nothing gold can stay.

Today's Route:   We left the entrance plaza at the Visitor Center and headed down the paved path, past the American South bed and across the Flower Bridge.  We passed through the China and Asia Section, the Rare and Endangered bed and across the Native American and Southeastern Tribes section, skirting the Herb and Physic Gardens before arriving at the Heritage Garden.  We then made our way down into the Flower Garden, concentrating on the cherries, crab apples and blueberries before heading back to the Visitor Center.

Cedar Waxwings basking in the sun.

As we gathered at the Visitor Center Fountain Plaza, we noticed a lot of activity in the Palatka Holly trees around the plaza. Many Cedar Waxwings were basking in the sun striking the upper branches, while others were foraging on the holly berries.

Japanese Maple leaf and flower

The Japanese Maples along the Visitor Center sidewalk have partially leafed out and begun to bloom. Maples, both native and exotic, are among the first trees at the Garden to flower. Our native Red Maples flowered in February and have gone to seed. Maples are monoecious, meaning that male flowers (with stamens) and female flowers (with pistils) are found on the same tree. Some maples are functionally dioecious, that is, they act or function as though the male flowers and female flowers are on separate trees. In maples, the male flowers on some trees don’t actually produce pollen, so that only the female flowers are actually functioning.  We looked at several female flowers on the Japanese Maples, their styles protruding out from the small, red flowers, and saw no stamen-bearing flowers, so perhaps this tree was functionally female. Maples are generally thought to be wind-pollinated: their flowers are inconspicuous and open in late winter before most insects are active. But bees do visit maple trees, especially Red Maples and Sugar Maples, to gather nectar so at least some of the pollination is carried out by insects. There is a nice article on Japanese maples at this website: https://naturewalk.yale.edu/trees/aceraceae/acer-palmatum/japanese-maple-42

Redbud showing cauliflory

Redbud flowers

Several Eastern Redbuds are in flower along the path into the International Garden. We stopped to admire the strange phenomenon of cauliflory, where flowers emerge directly from the bark of the branches and trunks of the trees. Some of the Redbud trees planted in the Garden may have been horticulturally selected to maximize cauliflory, but it also occurs frequently in wild trees as well. Cauliflory is mostly found in tropical shrubs and understory trees; Redbud is one of the few temperate species to exhibit this trait. Curious minds want to know: how and why? Studies done in just the last couple of decades have answered these questions. There are two parts to the “how” answer. Redbuds produce in each leaf axil up to ten “first order” flower buds that can remain dormant for up to five years and that flower sequentially on small branches during those five years. But what about the flowers on older, larger branches and even on the trunks? It turns out that first order buds have the ability to produce “second order” buds that go on flowering indefinitely on ever enlarging branches and trunks. And what about the “why” question, so dear to Ramblers, and often so hard to answer? Botanists know that the closest relatives to Eastern Redbud are tropical cauliflorous species, so this ancestral trait was apparently carried along as Redbuds evolved to live in temperate areas. But why cauliflory in the first place? What advantage does cauliflory confer on some tropical plants? Most tropical species with this trait are understory trees, attracting a different set of pollinators than the flowers in the upper reaches of the canopy. So perhaps cauliflory evolved to attract and provide nectar for the low-flying insects, such as heavy-bodied  bees, that never make it up into the canopy. For a more detailed discussion of cauliflory, this is a good article:  “Redbud Cauliflory: The Inside Story,” by John Hayden. https://scholarship.richmond.edu/biology-faculty-publications/127/

Chattahoochee Trillium with "youngsters"

Virginia Bluebells

Woodland Phlox

Several native wildflowers are flowering along the path into the International Garden, including Virginia Bluebells, Woodland Phlox, and a small “family” of Chattahoochee Trillium, with a large, flowering plant and various two- and three-leaved “youngsters” around its base that will mature and bloom over the next few years. 

Georgia Rockcress

Gerogia Rockcress closeup

There are several beds of Georgia Rockcress in full bloom in the International Garden. This is one of the most endangered species in Georgia, with only a handful of populations surviving in the northwest corner of the state near Rome and in the Fall Line, near Columbus.  They love rocky cliffs and bluffs, or perhaps they inhabit these stressful environments because there’s little competition. They are clearly flourishing in the rich beds at the Garden. Georgia Rockcress is one of the top priority species of the Georgia Plant Conservation Alliance and has also been nominated for federal listing as legally Endangered.

Pansy

The Flower Bridge is adorned with planters filled with large-flowered pansies, which some Ramblers were surprised to learn are actually cultivars of wild violets (in the genus Viola). The many shapes and colors of pansies are the result of artificial (human-induced) hybridization among several species in the section of the Viola genus called Melanium. Wikipedia tells us that the name pansy “is derived from the French word pensée (thought), and was imported into Late Middle English as a name of Viola in the mid-15th century, as the flower was regarded as a symbol of remembrance.”

The flowering stalk of Grass-leaf Sweet Flag

Planted among the pansies is a strange little plant with grass-like leaves and an erect spike of yellow-green flowers. It turns out to be Grass-leaf Sweet Flag, Acorus gramineus cultivar Ogon. Neither a sedge nor a grass, it's in the Sweet-flag or Calamus family, sister to all the other monocotyledonous plants. It is not native to US; native to Japan, Korea, and Eastern Asia.

The yellow-green spike (spadix) consists of tightly packed little ovaries that will become small red berries, if they are fertilized. Tucked in among the female flowers are tiny male flowers that will present their stamens later to prevent self-pollination.

Cupflower

At the back edge of the International Garden, there is a pretty little groundcover flourishing between the pavers. Known as Cupflower, it’s a white cultivar ‘Alba’ of a creeping species of Mazus.

Alabama Snow Wreath

The large hedge of Alabama Snow Wreath at the entrance to the Threatened and Endangered beds is in peak bloom. This is a beautiful shrub, with long, arching boughs covered with showy white flowers. The flowers have no petals, just a cluster of long, white stamens. Found in Georgia only in two northwestern counties, it occurs naturally in rocky, limestone-based forest soils. It spreads largely by underground stems; seeds are seldom seen. The genus Neviusia has only two species in it, ours (Neviusia alabamensis) and one other in California. It is in the Rose Family.

Pawpaw flowers

The Pawpaw trees

near the entrance to the Heritage Garden are covered with many buds and barely open flowers. Dark maroon in color, the flowers are thought to attract pollinating flies and beetles by a hue that suggests rotting meat. But however pollination occurs, it doesn’t seem to result in much fruit formation here at the Garden or elsewhere. In their article “Pollinator limitation, fruit production, and floral display in pawpaw (Asimina triloba),” Mary Willson and Douglas Schemske state that less than one percent of flowers produce fruit. Looking closely at the open flowers, Ramblers could easily see a well developed green ovary but no stamens, the “female” part of a given flower developing well before the “male” stamens, thereby preventing self-pollination. Perhaps this system works too well? Since Tall Pawpaws grow in large clonal colonies, pollen transferred from their closest neighbors, which are genetically the same plant, won’t result in fertilization. Flies and beetles have to travel long distances between pawpaw patches to effect cross-pollination and cross-fertilization. It is apparently established practice among commercial pawpaw growers to hang a dead animal in their pawpaw patches to encourage pollinators to move around among plants and patches!

Flowers of 'Belle of Georgia' peach

Several large ‘Belle of Georgia’ peach trees were blooming near the edge of the Heritage Garden. Peaches are in the same genus, Prunus, as cherry trees, which are also flowering now. Both have the characteristic bark trait of conspicuous horizontal rows of lenticels, the spongy tissue that allows the plant to uptake carbon dioxide through its bark.

Crabapple cultivar 'Louisa'

One of the Crabapple cultivars, 'Louisa,’ is flowering beautifully now at the edge of the Flower Garden, its sign prompting a discussion of the meaning of “cultivar” and how it differs from the term “variety.” The word “cultivar” is a portmanteau (a word that combines the meanings of two other words, like brunch); cultivar is simply shorthand for “cultivated variety.” A type of plant that has been developed horticulturally by hybridization or other artificial breeding techniques is called a cultivar and given a non-Latin name that is shown in single quotation marks, hence ‘Louisa.’  Usually the cultivar name is preceded by the Latin name: Malus angustifolius ‘Louisa.’

On the other hand, the term “variety” is applied by botanists to a group of plants that differs consistently, perhaps with a different leaf or flower shape, from other plants in that species in ways that suggest that the group is on the way to evolving into a new species. So: variety is used for the result of a natural process and cultivar is used for the result of an artificial process.

Henbit

Several weedy European wildflowers are flowering now in the edges of flower beds and in sidewalk cracks. These are among the first wildflowers that many of us learned – they are conspicuous and easy to identify, and, though exotic, are not invasive or found in natural areas. Henbit and Dead-nettle are both in the mint family, as their square stems, opposite leaves, and two-lipped flowers testify. Hairy Bittercress has leaves with up to nine rounded leaflets and the sharp odor of plants in the Mustard Family.

Two lichens

Some of the brick walls in the Heritage Garden are covered with patches of gold- and gray-colored lichens, whose identity await the arrival of lichen experts!

SUMMARY OF OBSERVED SPECIES:

Cedar Waxwings	Bombycilla cedrorum
Palatka Holly; hybrid of two native hollies	Ilex cassine x Ilex opaca
Japanese Maple	Acer palmatum
Eastern Redbud	Cercis canadensis
Chattahoochee Trillium	Trillium decipiens
Virginia Bluebells	Mertensia virginica
Woodland Phlox	Phlox divaricata
Georgia Rockcress	Arabis georgiana
Pansy	Viola section Melanium
Cupflower	Mazus reptans 'Alba'
Alabama Snow Wreath	Neviusia alabamensis
Primrose-leaved Violet	Viola primulifolia
Dwarf Sumac	Rhus michauxii
Paw Paw	Asimina triloba
Creeping Fig	Ficus pumila
Belle of Georgia Peach	Prunus persica
Flowering Crabapple	Malus angustifolius 'Louisa'
Rabbiteye Blueberry	Vaccinium ashei
Henbit	Lamium amplexicaule
Hairy Bittercress	Cardamine hirsuta
Several species of lichen