Ramble Report April 20 2017

Today's Ramble was led by Dale Hoyt.

Here's the link to Don's Facebook album for today's Ramble. (All the photos but one in this post are compliments of Don. The other photo is compliments of Emily.)

Today's post was written by Don, Linda and Dale.

Nineteen Ramblers met today.

Announcement:

Don will be doing a lunchtime presentation of the wildflowers, natural arches, and waterfalls he photographed during a recent photography safari to the region around Cumberland Falls, Kentucky. It will be in the Adult Classroom in the Visitor Center immediately following the Ramble and social hour next Thursday, April 27. Bring or purchase a lunch.

Today's readings were contributed by Don and Dale; their full text is in the Nature Rambler email with the link to this blog post.

Today's route: We left the Shade Garden arbor and went down the path to the Flower Bridge and past the Asia and China gardens to the Purple Trail, which we took down to the river, then turned left on the Orange Trail. At the base of the hill we took the trail up to the Heath Bluff.  After viewing the mountain laurel on the Heath Bluff, we returned to the Orange Trail and walked up river to the Orange Trail spur which we took back to the Visitor Center parking lot.

Path to Flower Bridge:

Yellowwood inflorescence

Linda stopped us briefly at the Yellowwood tree, which was blooming with pink flowers in large drooping inflorescences.

Heath Bluff Trail:

The Heath Bluff is unusual because several of the plants that grow here are more typical of the mountains. They appear to be relicts of the past glacial era when the climate was cooler. As the climate warmed the cooler adapted plants could not persist except in special microclimates, like coves and ravines that remained moister and cooler.

American toad; the prominent lumps behind the eyes are glands that secrete a toxic substance if the toad is grabbed by the jaws of a dog.

On the way up the hill Dale spotted an American toad, which, for the most part, remained placid in his palm for all to see. It eventually became aggravated with the photographers and jumped to the ground. Toads are active when the humidity is high and the temperature is low. Like all amphibians they suffer when it is dry, so you will only find them active at night or on days that are cool and moist or rainy. Otherwise they retreat to humid shelters under rocks, rotting logs or in the leaf litter.

Sooty mold fungus; the tan flower stalks above the mold are last year's Beechdrops.

 

Don spotted a large clump of Sooty mold fungus on the ground beneath an American Beech tree. A smaller mass was seen on one of the lower limbs, most likely formed during last summer's beech blight aphid infestation on the limbs above. A dark coloration was also seen on the buttressed roots of the tree, further evidence of the presence of the beech blight aphids last year or recent years previous. The fungus grows on accumulated honey dew, excreted by the aphids.

A few of last year's Beech drops were seen in the area near the American beech tree. Beech drops are annual parasitic plants that derive all their nutrients by attaching root-like structures called haustoria to the roots of Beech trees. The haustoria penetrate cells in the Beech tree’s roots and draw nutrients from the cells. The small amount of material they extract does not harm the trees. Since the Beech drops get all their nutrition from the host tree they have no need for chlorophyll and are not green. They are found elsewhere in the garden, so look for them where ever American beech is growing.

Mountain laurel flowers and flower buds

The first of many examples of Mountain laurel was seen, as we made our way further into bluff vegetation.The display this year was disappointing. In 2015 the path up the bluff was a solid wall of white blossoms.

Mountain laurel flower with stamens locked and under tension.
photo courtesy of Emily Carr

Each white Mountain laurel blossom has 5 petals and 10 stamens. Each of the petals has two pockets. The stamens are arranged in a circle surrounding the center of the flower, the ovary. The other end of each stamen bears a dark red anther, where the pollen is produced. When the flower opens the anthers are caught in the petal pockets and, as the petals open and spread, the stamen is bent, placing it under tension. Each stamen is like a medieval catapult, waiting to be triggered. The creature that releases the tension is usually a bumblebee. It stumbles over the stamens while searching for nectar. When the anther is dislodged from its petal pocket the stamen springs erect and the speed of its movement dusts pollen from the anther onto the bee. But what happens if no bee visits the flower or doesn't trigger the release mechanism? As the flower ages the petals lose water and wilt, freeing any stamens that are not already tripped. The shower of pollen that results falls on the flower's female parts as well as those of adjacent flowers, resulting in self-fertilization. Studies of natural populations of Mountain laurel estimate that only about 8% of the seed produced by a plant is the result of selfing. so the bees do a pretty good job.

Veiny hawkweed

We saw many examples of Rattlesnake weed (aka Veiny hawkweed) growing throughout the heath bluff. The leaves are very distinctive, being green and fuzzy, with many conspicuous purple veins. The flower heads are yellow and sit atop tall, spindly stems. Some plants may have several flowers on branches atop the stem. This species is in the composite family; the flower heads contain only ray florets – there are no disk florets.

Hawkweeds have an interesting history that begins with the discovery of genes. Our modern understanding of how genetic traits are inherited began in the 19th century with research conducted by the Austrian monk Gregor Mendel. He studied the inheritance of various traits in garden peas and published the results in an obscure journal where it received little attention and was not understood. He wrote about his pea studies to a prominent botanist who replied and encouraged him to conduct similar work with 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, i.e., the anthers must be removed before they are mature and releasing pollen. To do this Mendel had to carefully dissect open the florets while observing them with a magnifying lens. It was tedious, time consuming work and led to his failing eyesight. 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 asexually by a type of parthenogenesis called apomixis. This is how Dandelions produce seed – each seed is an identical genetic copy of the parent plant. All his painstaking crosses were futile because the pollen made no contribution to the developing seed. Mendel died believing that his research was of no significance.

Linda pointed out Georgia basil (aka Georgia Calamint) growing along the paths though a section of the heath bluff. When the foliage is bruised, it emits a strong “basily” or minty smell. It flowers July to September.

Sweet shrub flowers

Don ventured down to the lower slope above the open rocks by the river and found several beautiful Sweet shrub shrubs in full bloom with dark maroon flowers. (See last week's post for information about how it is pollinated.)

Large Galax inflorescence

Galax leaves and smaller infloescence

As we moved along the edge of the bluff, we found several Galax plants in full bloom, with the spires of small, white flowers on stems rising from the green and shiny round basal leaves.

Orange Trail, heading up-river:

We saw the first of many examples of Lyre leaf sage to be seen along the Orange Trail.

Butterweed

 

Before long, we began seeing lots of Butterweed, one of several species in the genus Packera found at the Garden. (The first species we see each year is Packera aurea, golden ragwort.)  The yellow flowers are found in large blooming displays atop and in the upper parts of the plants, which range up to or higher than four feet tall. The large patches seen along the floodplain looked quite impressive.

Multifloral rose; a beautiful but invasive plant

We saw Multiflora Roses growing in several trees on the banks of the river. It is a nasty invasive whose sale has been outlawed in several states, but, from a photographer’s standpoint, it has beautiful white and slightly pink flowers. At the same location as the multiflora rose, we saw Chinese privet blooming. Both of these invasive plants have been the target of invasive eradication efforts at the Garden.

Someone pointed out the large holes in some tall dead trees across the river. There was some discussion about what might be making these their homes but without an actual sighting of the bird (or squirrel) hanging around the holes, there is no telling exactly what is using them.

Sensitive fern

Numerous Sensitive ferns were seen along one particular stretch of trail.

Silvery checkerspot butterfly

Silvery checkerspot caterpillar

As we continued down the trail, someone noticed a Silvery checkerspot caterpillar and some frass on the underside of a wingstem leaf. Wingstem is one of the known host plants for the Silvery checkerspot butterfly. Many of the leaves on this particular plant showed evidence of being heavily grazed by these caterpillars. We later saw the adult butterflies actively flitting around. (We initially thought these were Pearl crescent butterflies, a similar looking species, but examination of Don's photograph revealed this error.)

Chinese privet in bloom

Gary took a few minutes to talk about the Chinese privet eradication program in the floodplain. In 2015 the privet was cut, using only hand tools, and the cut surface immediately treated with the herbicide glyphosate. This method is called cut stump treating. This past winter, emergent privet plants, which are easily recognized because they are winter green, were sprayed with glyphosate. These plants grew from both seeds and root sprouts. Spraying during the winter does not harm plants that are dormant at that time so it is effective against privet without undesirable side effects on native plants. Privet seeds have a short life in the seed bank, only one year. At present, there are only a few privet plants to be found and the current seed bank should be depleted soon. Future winter and spring floods may deposit more fruits in the floodplain but winter foliar spraying of the new seedlings that might show up should be a manageable task. The newly opened area is much sunnier now that the privet is gone. Such a habitat is susceptible to invasion by Japanese stilt grass, which can be controlled with a grass-specific herbicide, applied before it goes to seed. The size of the eradication program is about 10 acres. The dead brush piles where the cut privet was piled up make great wildlife habitat.

Blue toadflax

Katherine pointed out a little patch of Blue toadflax.

We saw lots of cleavers or bedstraw, with their extremely small, white and four petaled flowers growing in clusters from some of the leaf axils.

Linda pointed out the presence of Oriental false hawksbeard, an up and coming new invasive. She recommends pulling all of this plant that you come across.

Dale called me over to photograph a small wasp he found grasping the edge of a leaf.

Green tree frog

Avis was very excited to find one of the great finds of the day for us, a beautiful Green tree frog, perched on an intertwined mass of dead vines. In the Garden these tree frogs can be heard calling from the Beaver Marsh area. The vocalizations sounds something like a very loud and resonant: "Whonk! Whonk! Whonk!" Only the males call, hoping to attract a female mate. Calling is very energy intensive and in many species the males do not eat during the calling season. In some tree frogs "cheater" males hang out around a calling male, remaining silent. They attempt to intercept any female attracted to the caller and steal her away.

Wild garlic flower with mosquito

Right before the turnoff to the Orange Spur, we saw several Wild garlic plants in various stages of blooming from tight buds to beautiful pink flowers similar to spring beauty flowers. Mosquitos feed on nectar. Only the females feed on blood. They require the protein in blood to produce their eggs. The males continue feeding on their diet of nectar.

Right where we took a right on to the Orange Trail Spur, we saw a huge, fleshy mushroom emerging from a knothole on a dead, decaying tree. It was easily 8-10” across. Unidentified at this time.

Orange Trail Spur:

At the base of the hill, we saw lots of southern or wild chervil, with its tiny white flowers and carrot-like foliage. Growing with the wild chervil was lots of the exotic plant, ground ivy, a member of the mint family with small purple flowers. This plant is also called gill-over-the-ground, and was brought from England to flavor beer as an alternative to hops.

Carolina milkvine flowers

As we worked our way up the hillside on the trail, Linda was excited to see a Carolina milkvine sprawled across a fallen dead tree and sporting dark maroon star-shaped flowers. The leaves are large and heart-shaped. Milkvines are related to Milkweeds, the host plant for the Monarch butterfly, so some people wonder if the Monarch caterpillars could feed on Milkvines. The answer seems to be no, but the butterfly does lay eggs on Milkvine. It would appear that the caterpillars cannot complete development on the plant.

Growing at various locations along the trail we saw violet wood sorrel in small patches with its green shamrock-shaped leaves marked with dark spots or patterns on each leaflet.

Ladybug larva (R); winged aphids (L)

As the group spread out a bit on the home stretch, someone noticed a low growing plant at trail side with a ladybug larvae and some small, winged aphids.This may have been a fortuitous find but it was appropriate. Ladybug larvae and adults are voracious consumers of aphids. The two winged aphids on this plant couldn't have picked a worse place to start an aphid colony!

Two winged aphids from photo above.

Aphids have an interesting and complex life cycle. In its simplest form the winged females function as dispersal agents -- they are the ones that seek out new host plants. When they find the appropriate plant they begin laying eggs. These eggs hatch into wingless, all female forms that stay on the host plant, sucking sap and making new aphids without having mated. In some cases the eggs begin developing inside the mother and tiny aphids are born instead of eggs. Some of these tiny aphids have developing embryos inside them. You can see that a colony of aphids can increase very rapidly. Later in the season some of the aphids start producing winged forms, both male and female. These fly off, mate and fly to find new hosts, often on a different species of plant. There they will lay eggs that overwinter and start the cycle anew the following spring.

Redbud sapling; semicircular cutouts on the margins of the leaves are made by Leafcutter bees.

Dale noticed a young and tender Redbud sapling with odd, semi-circular spaces removed the margins of the heart-shaped leaves. Leaf cutter bees land on the edge of a leaf and chew out a piece, which they carry back to their nest to plug the opening. The nest is a hollow opening in a stem and it is filled sequentially with a mass of pollen and nectar on which an egg is laid. The food and egg is then isolated by a plug made from the cut-off piece of leaf. Then the process is repeated until the bee runs out of stem. Redbud leaves are favored, but any tender, easily cut leaf can be used. We saw evidence of more leaf cutter bee activity on a nearby water oak sapling.

Poison Ivy flowers and buds

Linda noticed that a small Poison ivy vine growing up a trail-side tree was flowering. The flowers were mostly in the bud stage, at this time, but a few small yellow flowers were present.

Jack in the pulpit

As we made our way up the hill, we passed several trillium (Sweet Betsy and Pale Yellow) still blooming, as well as several Jack-in-the-pulpits, which had 4 leaflets per leaf, instead of the more usual 3 leaflets.

SUMMARY OF OBSERVED SPECIES:

Yellowwood tree	Cladastris kentuckea
American toad	Bufo americanus
Sooty mold fungus	Scorias spongiosa
Beech drops	Epifagus virginiana
Mountain laurel	Kalmia latifolia
Rattlesnake weed	Hieracium venosum
Georgia basil	Calamintha georgiana
Sweetshrub	Calycanthus floridus
Galax	Galax urceolata
Lyre leaf sage	Salvia lyrata
Butterweed	Packera glabella
Multiflora rose	Rosa multiflora
Chinese privet	Ligustrum sinense
Sensitive fern	Onoclea sensibilis
Silvery checkerpot (buttterfly and caterpilla)	Chlosyne nycteis
Wingstem	Verbesina alternifolia
Blue toadflax	Nuttallanthus canadensis
Cleavers or bedstraw	Galium aparine
Oriental false hawksbeard	Youngia japonica
Wasp	Order Hymenoptera
Green tree frog	Hyla cinerea
Wild garlic	Allium canadense
Mosquito	Family Culicidae
Southern or wild chervil	Chaerophyllum tainturieri
Ground ivy	Glechoma hederacea
Carolina milkvine	Matelea carolinensis
Violet wood sorrel	Oxalis violacea
Ladybug (larvae)	Family Coccinellidae
Winged aphids	Family Aphididae
Redbud tree	Cercis canadensis
Leaf cutter bee (evidence)	Family Megachilidae
Poison ivy	Toxicodendron radicans
Sweet Betsy trillium	Trillium cuneatum
Pale Yellow trillium	Trillium discolor
Jack-in-the-pulpit	Arisaema triphyllum