Ramble Report April 19 2018

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 & Dale Hoyt.

38 Ramblers met today.

Announcements:

Saturday, April 28^th, the Friends of the Georgia Museum of Natural History will be holding their annual meeting at the museum annex at 12:00 p.m., followed by a meeting of the Science Cafe folks, at 1:00 p.m. All Ramblers are invited to the Annex to view the collection of Whale skeletons.

Today's reading: Linda read a Louisa May Alcott poem, Mountain Laurel. You can find the text here. Next, Bob Ambrose, Jr., recited his most recent poem: A Dream of High Spring (you can find the full text here).

Today's Route:   We walked through the Big Room in the conservatory then made our way through the Herb and Physic gardens to the Threatened and Endangered Plant section.  We then headed around the big rock to the head of the Purple Trail, which we took to the new Hi Water Trail.  We took this down to it's crossing over the stream to the Orange Trail.  We then walked down the Orange Trail to the path up to the Heath Bluff.  Leaving the Heath Bluff, we took the Orange Trail down to the river, stopping briefly at the beaver pond wetlands before walking up the river to the Purple Trail, which we took back to the Visitor Center where we enjoyed refreshments and conversation at the Cafe Botanica. 

Edge of Physic Garden:

Yellow Flag Iris, an exotic species with some potential to become invasive.

Path along Threatened and Endangered Species Section:

Sand Rosemary

Sand Rosemary – Not native to Georgia, found in Florida panhandle and west to Mississippi in dry, sandy habitats. It’s a woody mint, with typical mint family traits of square stem, opposite leaves, and two-lipped flower.     

Lyre-leaved Sage flowers

Lyre-leaved Sage basal leaves
(shaped like a Lyre?)

Lyre-leaved Sage –  A native but weedy species, also in the mint family.

Wild Blue Indigo

Blue Wild Indigo – Our only blue-flowered Wild Indigo, it has typical bean family flowers with an upright banner petal, two wing petals, and a keel petal (pale green). It takes a large insect, such as a bumblebee, to push its way between the wings and keel to reach the nectar.

Native American Southeastern Tribes:

Royal Fern

 

Fern "ball" constructed by a caterpillar

Royal Fern

Most ferns bear their reproductive structures – sori – on the underside of the leaves. Royal Fern takes a different approach; its sori are located on specially adapted leaflets clustered at the top of a few fronds. These fertile fronds are shorter than the sterile fronds.

We noticed a group of fern leaflets rolled up to form a hollow ball at the end of one of the fronds. In past years we have seen these fern "balls" on Christmas Fern elsewhere in the garden. The full story what causes the balls can be read  here. 

It is unusual to see evidence of herbivores eating ferns because most ferns are protected by toxic chemicals in their tissues. The chemicals are expensive to synthesize, so the fern waits until it is attacked before it increases its toxic content. The caterpillars that make the balls feed on the fern tissue for a shot period of time, apparently until the toxins become to much to tolerate. Then the caterpillar leaves its ball and crawls to a nearby fern that has not been attacked. It may change host plants several times before it reaches the size to pupate.

The new living roof over the shed at the front of the building is flourishing with plantings of Christmas Fern, Seersucker Sedge, and Wood Rush.

Purple Trail:

American Beech with fused trunks

We stopped to admire an American Beech with three trunks grown together at several places. Since this is botany, there is of course a special term for this process: inosculation or self-grafting. When two or more branches or trunks grow close together, they may abrade each other during high winds, rubbing off the outer bark and exposing the inner cambium layer. Cambium cells are rapidly dividing cells that in this case fuse with the cambium layer on the other abraded branch or trunk if the contact is sustained. After the cells fuse, bark grows around the wound, joining the branches and sealing the partnership. Obviously, thin-barked trees such as Beech trees are more prone to inosculation, as are maples, ashes, and many types of fruit trees. Inosculation can also happen between unrelated trees, such as a hardwood and a conifer, if they come into sustained contact with each other.

Possumhaw (or Deciduous Holly) is just coming into flower. We were able to confirm that this plant is male–the opened flowers all had stamens but no pistils. Since we’ve never seen fruit on this plant, we’d assumed it was male but it was nice to confirm it.

Hi Water Trail:

Wild Ginger

Wild Ginger is putting up new leaves but no flowers were seen.

Jack-in-the=Pulpit

Jack-in-the-Pulpits are common along the upland, mid-slope portion of this trail, surprisingly since Jacks are typically found in bottomlands or lower moist slopes. Several smaller plants were in flower, and will probably bear male flowers. Only larger, more robust plants will produce the energy-expensive female flowers and fruits. We've seen the Jack, now where is the Jill? You can find out in this post.

Kidney-leaf Buttercup

Basal, kidney shaped leaves of Kidney-leaf Buttercup

  

Hooked Buttercup flowers & fruits

Hooked Buttercup – Look closely in the center of buttercup flowers to see a tight cluster of tiny fruits, each tipped with a minute hook. When the fruits mature, the hook hardens and is capable of being carried on fur, feathers, and socks.

Orange Trail:

Sensitive Fern
Fronds show damage from herbivores

Sensitive Fern
Fertile frond from last year

At bridge:  Sensitive Fern, with last year's fertile fronds; raccoon tracks in mud

Heath Bluff:

Mountain Laurel flowers
The red anthers are held by pockets in the petals until released by bees.

Mountain Laurel has begun blooming; each white flower has five petals, each dotted with two dark red dots. A closer look will reveal that every dot is really an anther (the flower structure that produces pollen) held in a recess in the white petal. Attached to the anther is a translucent white filament, whose other end is attached to the ovary at the center of the flower. It's not obvious from just looking, but each stamen (the filament and attached anther) is under tension, the secret to the flower's pollination mechanism.

Bumblebees are the most common visitor to Mountain Laurel flowers. They seek two things from a flower: nectar and/or pollen. As the visiting bee stumbles around the flower bowl it bumps into a stamen, releasing the anther from its pocket in the petal. The stamen, which was under tension, springs upward like the arm of a medieval siege weapon, dumping a cloud of pollen on the bee. The pollen adheres to the bristles that cover the bee, so when it visits other flowers some of this pollen will be brushed onto the female structures, thus fertilizing the plant.

By using a toothpick you can mimic the action of a bumblebee and spring the stamens yourself.

A recent publication, “Dispensing pollen via catapult: Explosive pollen release in mountain laurel (Kalmia latifolia)” measured the speed with which the pollen is hurled through the air, 8 mph. This link has two short, slow motion videos that show the release mechanism in action.

Veiny Hawkweed flower

Veiny Hawkweed leaves

Veiny Hawkweed
Another, older, name for this plant is Rattlesnake Hawkweed, so called because it was reputed to cure the bite of rattlesnakes.But in this genus, Hieracium,  have an interesting historical connection. Our modern understanding of genetics, how traits are inherited, was discovered in the 19th century by the Austrian monk Gregor Mendel who studied garden peas. After publishing his paper on the inheritance of traits in peas Mendel turned his attention to Hawkweeds. Making crosses in Hawkweeds is tremendously difficult because they are composites – their "flower" is really a collection of tiny florets, each floret capable of producing a single seed. In order to be sure that the pollen used in a cross is the only pollen that can fertilize the egg the pollen recipient has to be emasculated. The anthers must be removed before they are mature and releasing pollen. To do this Mendel has to carefully dissect open the flowers while observing them with a magnifying lens. It was tedious, time consuming work and may have caused his eyesight to fail. None the less, Mendel persevered for five years and discovered that the inheritance patterns he had discovered in garden peas were not seen in hawkweeds. He died disappointed and unappreciated, foiled by the fact, unknown to him and other botanists of the time, that hawkweeds reproduce by parthenogenesis, a type of asexual reproduction. All his painstaking crosses were futile because the pollen made no contribution to the developing seed.

Yellow Star Grass

Galax flower stalk with buds

Galax is commonly found on Heath Bluffs in the Piedmont and the Blue Ridge, often growing with Mountain Laurel and Sourwood, as is the case here at the Garden. It should be in full flower in a week or two.

Sweet Shrub

Sweet Shrub is an ancient group of plants, with beetle-pollinated, maroon flowers. Their spicy-floral fragrance led to their use as a form of perfume, as girls would drop them down the fronts of their dresses – hence another common name:  Bubby Bush. A yellow-flowered form bears the cultivar name ‘Athens.’ Its flowers are especially fragrant. Both maroon- and yellow-flowered forms make great landscape plants that can be pruned into dense, compact shapes. Since Sweet Shrub flowers only on new growth, hard pruning will lead to lots of new stems and lots of flowers on the new stems. They often spread by underground stems to form a small colony.

Orange Trail, at Beaver Pond spillway:

Common Snapping Turtle

A Common Snapping Turtle was climbing up the soil next to the dam and spillway of the beaver pond. This probably is a female searching for a place to lay her eggs. Eggs are laid between later April and early June. The turtle excavates a hole with her hind legs, scooping out soil one footful at a time. When finished she lays from 20 to 50 eggs in the hole and then carefully scoops the excavated soil over the hole. When she is done you can scarcely tell that the soil has been disturbed. But animals like Racoons can smell the eggs and often dig them up, destroying the nest and eating its contents.

Purple Trail:

Green-and-Gold

Common Wood Sorrel

SUMMARY OF OBSERVED SPECIES; B = Blooming

Common Name(s)	Scientific Name	Comment
Yellow Flag Iris	Iris pseudacorus	B
Chaste tree	Vitex agnus-castus
False Rosemary	Conradina canescens	B
Lyre-leaved Sage	Salvia lyrata	B
Blue Wild Indigo	Baptisia australis	B
Royal Fern	Osmunda regalis
Christmas Fern	Polystichum acrostichoides
Seersucker Sedge	Carex plantaginea
Wood Rush	Luzula sylvatica
Horse Sugar	Symplocos tinctoria
American Beech	Fagus grandifolia
Possumhaw Deciduous Holly	Ilex decidua	B male
Wild Ginger	Hexastylis arifolia
Jack-in-the-Pulpit	Arisaema triphyllum	B
Red Maple	Acer rubrum
Kidney-leaf Buttercup	Ranunculus abortivus	B
Hooked Buttercup	Ranunculus recurvatus	B
Sensitive Fern	Onoclea sensibilis
Raccoon	Procyon lotor	tracks
Mountain Laurel	Kalmia latifolia	B
Veiny Hawkweed	Hieracium venosum	B
Yellow Star Grass	Hypoxis hirsuta	B
Galax	Galax urceolata
Sweet Shrub	Calycanthus floridus	B
Georgia Basil	Clinopodium georgianum
Common Snapping Turtle	Chelydra serpentina
Green-and-Gold	Chrysogonum virginianum	B
Common Wood Sorrel	Oxalis stricta	B