Wednesday, March 11, 2015

Ramble Report March 5 2015

After two cancelled rambles we finally got a break in the weather and 21 eager ramblers gathered for the first Ramble of the year.

Most of the photos for the ramble are taken from Don Hunter's album (the link is here); I supplied the hickory photos.

Today's reading was provided by me: the poem Learning the Trees by Howard Nemerov.

Today’s route:  We took the paved walkway from the arbor down through the Shade Garden and entered the Dunson Native Flora Garden. From the DNFG we walked down the power line right-of-way to the river and then turned left on the Orange trail to look at the progress of the privet eradication program. We then turned around and went back to the parking lot via the White Trail spur.

Shade garden: 
Mockernut nut; note ridges
If you look at the edges of the walkway you'll still find the fallen husks and nuts of hickory trees from last fall. There are two kinds of hickory growing in this location: Mockernut and Pignut. The fruits (husk + nut) of these trees are very different. The
Mockernut produces a larger, thick husked fruit and the nut within is has prominent ridges. The Pignut
Mockernut (R) Pignut (R) with partial husks
fruit is smaller, has a thinner husk and a smoother, almost spherical nut. Most of the nuts have been eaten by this time of year, but you can still find some that are partially intact. You can see from the photo of the eaten nuts that the two differ in thickness of the nut wall. I still would like to know what animal has so neatly cleaned the nut meat from the shell.
Mockernut (L.); Pignut (R.) compared

Toward the bottom of the walkway is a large Sycamore tree and the sidewalk is
Sycamore seeds
strewn with the seeds from this tree. If you can bend over far enough you can see the Sycamore seed balls still hanging from the upper branches. Each seed ball is a spherical cluster of seeds produced from a spherical inflorescence that bloomed last spring. As the season progresses the seed
Sycamore seed ball fragmenting
balls fragment, releasing hundreds of seeds that are carried in the wind by golden hairy parachutes, one seed per flower.

The American Sycamore is similar in appearance to a tree called the "London Plane" and no wonder. The London Plane is a hybrid between the Oriental plane (Platanus orientalis)and the American Sycamore (Platanus occidentalis) and is widely planted in Europe and American cities in the northeast. The story of how this happened is well told here.

Vine attached to shed Sycamore bark
When young a Sycamore has smooth, flaky bark that spontaneously peels off, revealing a lighter colored layer beneath. This gives the young trunk an appearance reminiscent of camouflage. But as the tree grows the bark on the lower trunk becomes thicker, darker and ridged. But the upper limbs and branches still retain their youthful texture and coloration. Why? Because all trees grow from the ends of their branches, so the upper parts are the newest.

Why does the Sycamore bark flake off? One hypothesis is that the shedding of bark may be an adaptation to prevent vines from climbing up the tree. In the Dunson garden we saw evidence that is consistent with that idea. A young Sycamore there has a vine that is still attached to some loose bark flakes.

Bigleaf Magnolia bud
Spring is finally approaching when you see buds beginning to swell and we found the enormous buds on a Bigleaf Magnolia near the Sycamore and on an Ashe's Magnolia a little further away.

Dunson Native Flora Garden: Another sign of spring is the appearance of plants in the mustard family with their tiny, four-petaled flowers. There are several species, but we think we saw Hairy (or Hoary) bittercress. Look for these plants in disturbed places in your yard. (Martha remembers them as "Creasy Greens," a childhood spring-time food.

The leaves may not have appeared yet but it is still possible to identify some trees by the characteristics of their bark. Northern red oak has bark that is thrown up in ridges with smooth, flat tops. The ridge tops are lighter in color and when viewed from below seem to trace out trails that run up the trunk. Dan Williams refers to these as "ski trails" to help us remember that they are found on Northern red oaks -- northerners have enough snow to ski in the winter. The Southern red oak lacks these "ski trails." (But one other oak in our area, the Scarlet oak, also has ski trail bark.)

Many wildflowers are beginning to appear in the Dunson Garden, some are just showing their leaves, some have flower buds and a few actually have blossoms.

Leatherwood flowers
One of the surprises was the Leatherwood. The day before all the flowers I examined were still buds, but today they were all open. In one patch Bob found that they were being investigated by Honey bees. The bees survive the winter by consuming the honey stored in their hive, but to provide the protein necessary for the growth of new bees they have to forage for pollen. The bees I saw had their pollen baskets full of Leatherwood pollen.

Chattahoochee trillium with bud
The Chattahoochee trillium has prominent buds, but the Spring beauty is mostly just present as grass-like leaves. The patch of Trout lilies we have seen in previous years is back, but none seem to have flowers as yet. We did find one blooming Dimpled
Trout lily
trout lily but could not locate the others that we saw last spring. We also found the leaves of a few Cranefly orchids, which will disappear in another month or so, to be replaced by a flowering stalk in mid summer. The
Golden ragwort
Golden ragwort that is so abundant and widespread in the garden is just beginning to bud. Some of the Cutleaf toothworts were in bloom, but most were just recently emerged. Some Virginia bluebells were peaking above ground and one even had an open flower. Other wild flowers that were up but lacking flower buds were Heart-leaf wild ginger and Shooting stars.

There were some animal surprises as well.
Net-winged beetle
George found a small, brilliant red Net-winged beetle (Family Lycidae). When you see a brightly colored insect it usually is distasteful or mimicking a similar-colored distasteful insect.

We also found two slugs, one on a patch of moss and the second feeding on a lichen.

Power line & Orange trail: In the greatly disturbed area of the Power line right-of-way we found two introduced species in bloom: Purple dead nettle and Ground Ivy. These are common "weeds" in lawns and other disturbed places and are among the earliest plants to bloom in the spring.

Thomas Peters has done a remarkable job of clearing out the Chinese privet along the Orange trail, all done with a hand saw. It will be very interesting to see what (besides more privet) comes up in the area. Already we can see small shoots of Elderberry appearing. There are only a few ways that plants can survive in an area that has been dominated by privet. One is to linger on beneath the privet canopy subsisting on the little sunlight that
Elderberry -- new growth
penetrates the privet canopy. Another is to be in the soil seed bank, the collection of dormant seeds that can be found in most soils. The problem with both strategies is that over time the seeds get infected by fungi or are eaten by animals or simply die. The longer an area is covered by privet the fewer the surviving seeds in the soil below. The privet has been growing in the area for many decades so it will be interesting to see what plants have managed to hang on. One note of hope -- we found a small shoot of Elderberry emerging from the ground that had been shaded by the privet.

After gazing on the empty space left after the privet clearance we returned back to the parking lot and our usual beverage and conversation at Donderos'.

Common Name
Scientific Name
Pignut hickory
Carya glabra
Mockernut hickory
Carya tomentosa
American Sycamore
Platanus occidentalis
Big leaf magnolia
Magnolia macrophylla
Hairy bittercress
Cardamine hirsuta
Northern red oak
Quercus rubra
Old man’s beard lichen
Usnea strigosa
American Holly
Ilex opaca
Chattahoochee trillium
Trillium decipiens
Spring beauty
Claytonia virginica
Trout lily patch
Erythronium americanum
Dimpled trout lily
Erythronium umbilicatum
Crane fly orchid
Tipularia discolor
Ashe’s magnolia
Magnolia ashei
Sourwood tree
Oxydendrum arboreum
Golden ragwort
Packera aurea
Carolina mantleslug
Philomycus carolinianus
Shooting star
Dodecatheon sp.
Cutleaf toothwort
Dentaria laciniata
Liquidambar styraciflua
Heart leaf wild ginger
Hexastylis arifolia
Dirca palustris
Virginia bluebell
Mertensia virginica
Trout lily blooming  
Erythronium umbilicatum
Spotted trillium
Trillium maculatum
Net-winged beetle
Lycidae: Dictyoptera sp.
Purple deadnettle
Lamium purpureum
Ground ivy
Glechoma hederacea
Sambucus canadensis

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