Right at the end of Charter Oak Court is this beautiful Kousa dogwood (
Cornus kousa), which is native to eastern Asia. Compare the
description from Ohio State University and the
Virginia Tech tree fact sheet. All pictures in this post taken September 22, 2009, unless otherwise noted.
The most obvious aspect of the Kousa at this time of the year is its abundance of red compound berries. Picture taken evening of September 21.
A closer look at one of the compound berries, which looks rather like a spiky red soccer ball. Picture taken evening of September 21.
The berries are beginning to drop en masse, leading to quite a collection of fruit at the base of the tree. Given that this is in a manicured lawn, there is no chance that any of these seeds will actually result in a new tree. The Kousa is also not mentioned in either the Digital Atlas of Virginia Flora or the Checklist of Washington-Baltimore Area Flora, indicating that this tree is purely a planted ornamental and does not grow in the wild in our area. Picture taken evening of September 23.
A bit further up the street/parking lot at Charter Oak Court is this pignut hickory (
Carya glabra), also in full fruit. Compare the
Virginia Tech tree fact sheet. Photo taken evening of September 21.
I found this
very useful key to hickories from Vanderbilt University. From this I was able to identify my hickory as a pignut. As this picture shows, the leaves generally have 5 leaflets, which (in step 3 of the key) narrows it down to either pignut or shagbark hickory - and my specimen does not have a shaggy bark.
Moreover, the fruit have the unique pear shape of pignuts - see this
gallery of hickory fruit and compare my specimen to those in the second row on the left. Picture taken evening of September 21.
While quite a few of the fruit still remain on the tree, many nuts have also already fallen, littering the ground beneath the tree. And as is evident from this shot, the local fauna (most likely squirrels) has been happily nibbling on them!
While the pignut at Charter Oak Court is a tended ornamental, I also found this wild pignut along the forested portion of the W&OD gravel path just north of Sunset Hills Road. If you look closely at the high-resolution version of this picture, you can see at least three fruit still hanging on this tree.
A bit further north on the W&OD gravel path, near the top of the stony slope as you walk toward Michael Faraday Court, is this chestnut oak (
Quercus prinus), with its characteristic crenately lobed (but untoothed) leaves and large acorns - see the
Virginia Tech tree data sheet. In this picture, which was taken with the camera pointing pretty much straight up, one acorn can still be seen hanging near the center.
The peak of the acorn drop for chestnut oaks was about two weeks ago, and the path underneath this particular oak is still completely littered with fruit.
This oak clearly reproduces in the wild, as shown by these two youngsters nearby (yes, these are rooted seedlings, not just fallen branches).
At the bottom of the large dip in the W&OD gravel path between Wiehle Avenue and Michael Faraday Court is this dense clump of late-flowering thoroughwort (
Eupatorium serotinum). Note the patches of summer grape (
Vitis aestivalis), with their large heart-shaped leaves, lurking in the undergrowth. See yesterday's post for more on these plants.
Here is a close-up of a flowering dogwood (
Cornus florida) in the hedgerow that separates the W&OD gravel path from the Pizza Hut parking lot at Wiehle Avenue. The buds that will open up to form next year's new leaves and flowers are already clearly visible. Looking closely at the clusters of berries one can also see that not every flower has developed into a berry; there are clusters of about 10 flowers each, with only three or four berries and the remaining flowers now undeveloped.
Back at Charter Oak Court, the color is definitely turning on the red maples (
Acer rubrum). It is my understanding that tree leaves contain a number of different pigments, including orange carotenoids as well as the deep green chlorophyll. Once chlorophyll has been deployed in a leaf, it dominates all the other pigments. Chlorophyll has to be continually regenerated, and in the fall this process becomes less efficient and essentially restricted to the areas close to the leaf veins. At the same time, production of red anthocyanins kicks in in the areas abandoned by chlorophyll (see
this Wikipedia article for a more comprehensive explanation). The spatial restriction of chlorophyll production can be clearly seen in these leaves, which are still green in the areas immediately adjacent to the leaf veins but russet in the outlying areas.
Leaves on another red maple at Charter Oak Court, once again showing the delicate green vein pattern that results from the gradual shutdown of chlorophyll renewal in these leaves.
