Morning of August 6, 2010 (continued)

In the thicket on the south side of the W&OD bike path where it crosses the pipeline easement one can now find this bushy plant with sessile opposite leaves at its branching points and what appear to be five-petalled flowers in bloom.  This is flowering spurge (Euphorbia corollata, see this Missouri description and this Illinois article).  This plant is related to the poinsettia, and as with that species, the brightly colored structures are not petals, but rather modified leaves.

The shining or winged sumac (Rhus copallinum) is just about finished blooming, and the small seeds are beginning to set.  For how this plant will look in about six weeks, when the seeds have ripened, see this post from last September.

Another plant commonly found along the W&OD bike path that is now in the final stages of flowering:  the devil's walking stick (Aralia spinosa).  These plants have grown massively from the gnarled solitary sticks that first opened their buds in April, as seen in this post and this post.

As can be seen in this closer-up shot, the flower petals have now generally fallen away, and only the fertilized ovaries now remain that are beginning to set as fruit.

Devil's walking sticks lining both sides of the W&OD bike path, looking west from a point just west of the intersection of the bike path with Wiehle Avenue.  For how this scene will look in a couple of months, when the berries have turned black and the stalks bearing them are purple, see this post from last October;  the first picture there was taken from a point maybe 20 feet east of the photo here.

And a final shot showing sumac and devil's walking stick together in a thicket between the W&OD bike path and the W&OD gravel path just west of Wiehle Avenue.

Yet another striking plant that is now spectacularly in bloom is hollow Joe Pye weed (Eutrochium fistulosum, formerly Eupatorium fistulosum;  see this Missouri description, this Connecticut gallery, and this Wikipedia article).  This cluster is on the south side of the W&OD bike path, just east of its intersection with Isaac Newton Square and a couple hundred feet west of the devil's walking sticks shown just above.

This closer-up image shows the sagging flower heads composed of numerous tiny pink flowers that are very similar to the white-flowering thoroughworts seen in this post from last September.

The Joe Pye weeds are extremely popular with butterflies, such as the yellow swallowtail seen in this picture.  Two months ago these same butterflies were noshing on the flowers of common milkweed, as seen in this post;  remarkably, the milkweed flowers are the exact same shade of pink as the Joe Pye weed flowers.

The outcome of that earlier butterfly-noshing:  mature seedpods of common milkweed (Asclepias syriaca), taken from the same spot in the median between the W&OD bike path and the W&OD gravel path south of their intersection with Sunset Hills Road as the June flower shot referred to just above.

Hidden in the undergrowth along the south side of the W&OD bike path between Isaac Newton Square and Wiehle Avenue one can find this dainty flower with two bright blue lobes and prominent yellow false anthers.  This is Asiatic dayflower (Commelina communis, see this Missouri description);  the specific identification is enabled by the fact that it has only two rather than three blue lobes on the flower.

Finally, on the west side of the W&OD bike path just south of the Dulles Toll Road one can find this purple-flowering plant with protruding yellow anthers.  This is bittersweet nightshade (Solanum dulcamara, see this Missouri description and this Wikipedia article), which is an invasive relative of the Carolina horsenettle (featured here) and the tomato.  Note the small green fruit (quite poisonous) in the upper left corner of the image.

June 8, 2010

This strikingly handsome purple-leaved small tree with wispy flowers is found on the south side of the W&OD bike path immediately west of the American Dream Way bridge.  There are several more specimens in the median between the W&OD bike path and the W&OD gravel path near the Fannie Mae Gardens.

This is a smoketree (Cotinus coggygria, see this Virginia Tech fact sheet, NC State fact sheet and this Wikipedia article), which is a relative of the sumacs

In a clearing south of the W&OD bike path across from the Fannie Mae Gardens is a thicket of this plant, whose flower resembles a small thistle but whose leaves and stems are far less spiny.  This appears to be a knapweed (Centaurea spp.), and may be the highly invasive spotted knapweed (C. maculosa, see this Missouri description and this Wikipedia article).

Pokeweed (Phytolacca americana) is beginning to bloom, as here on the north side of the W&OD bike path near Isaac Newton Square;  see this post from last September for how pokeweed appears once it fruits out.

 A couple of small flowering plants hidden in the grass west of the W&OD bike path south of Sunset Hills Drive.  The white five-petaled flower with prominent anthers appears to be Carolina horsenettle (Solanum carolinense), already featured before in this post from last October.  The small pink-flowered plant next to it with the reddish stem and comparatively large lanceolate leaves appears to be some form of knotweed, perhaps tufted knotweed (Polygonum caespitosum, compare this Virginia Tech weed guide and this Connecticut description), even though the Digital Flora of Virginia does not list this species.

No doubt about this species - this is common milkweed (Asclepias syriaca), now bursting into flower in this thicket on the south side of the W&OD bike path across from the Fannie Mae Gardens.

Close-up of an inflorescence.  Compare the Missouri description.

Milkweed flowers are apparently quite popular with insects.  Here is a shot with two large butterflies feeding on separate inflorescences;  these plants are located in the median between the W&OD bike path and the W&OD gravel path just south of Sunset Hills Drive and north of the Dulles Toll Road bridge.

And here is a shot with a bee of some sort.

Afternoon of October 19, 2009

After 5 days of rain, finally a sunny fall day!

These are the field thistles (Cirsium discolor) that are between the W&OD bike path and W&OD gravel path just north of the Dulles Toll Road bridge.  For pictures of them in flower almost three weeks ago, see this post.

Now the thistles have gone to seed, with the seeds located at the bottom of tufts of long white hair that will carry them away with the wind.

Along the W&OD bike path between Sunset Hills Road and Michael Faraday Court one frequently encounters sassafras (Sassafras albidum) in the understory.  These trees are easily identified by their trident-shaped leaves.  Compare the Virginia Tech fact sheet.  The leaves are now beginning to turn to attractive yellows to reds.

Here is an earlier view of an understory sassafras tree along the W&OD bike path just north of Sunset Hills Road taken exactly four weeks ago.

On the north side of the W&OD bike path just west of Michael Faraday Court there is a stretch of about 20 feet where one will encounter frequent specimens of this grass.  From Lauren Brown's Grasses:  An Identification Guide, I believe this is rye (Secale cereale) and not one of the native wild ryes (Elymus spp.), because the head of fruit has rather long bristles and sometimes nods.

Secale cereale is the rye that is cultivated and from which rye bread is made.  But it also readily escapes from cultivation and can become weedy along roadsides and abandoned railroads - which is exactly what the W&OD trail is.  Given that, fifty years ago, this land belonged to the A. Smith Bowman distillery, which used rye (among other grains) to produce its Virginia Gentleman bourbon, it is entirely possibly that rye used to be cultivated in this particular patch and has persisted as a weed.

On the south side of Sunset Hills Road, between Isaac Newton Square and the pipeline, at the northwestern corner of the BAE Systems property, is this beautiful ornamental sweetgum (Liquidambar styraciflua), with its distinctive palmately lobed leaves.  Compare the Virginia Tech fact sheet.

This tree is now gloriously full with the characteristic gumball fruit.

Further west along the south side of Sunset Hills Road, the northern edge of the Plazamerica property is lined with ornamental sawtooth oaks (Quercus acutissima).  These oaks have long slender unlobed leaves like the willow oaks (Q. phellos) shown in this post, but are definitely a different species - note the bristly spines along the leaf edges and the exuberant fringe of scaly outgrowths covering the acorn cups.  Compare the Virginia Tech fact sheet.

Like the willow oak, the sawtooth oak belongs to the red oak group, which has acorns maturing in two years (unlike the white oak group, whose acorns mature in just one year).  The previous image showed some dark brown and mature acorns;  this picture, taken from the same tree, shows a green immature acorn that thus appears to be a year younger than the previously shown ones.

This tree, slightly further west than the previous one and more exposed to the sun, appears even further in its development - it has already dropped its mature acorns, leaving behind just the fringed cups.

Along the north side of the Plazamerica parking garage, fronting Sunset Hills Road, is this ornamental planting of oak-leaved hydrangea (Hydrangea quercifolia), which is acquiring a very attractive fall coloration.  Compare this data sheet from Missouri.

Let us now return to wildflowers!  Nestled among the mile-a-minute vines that infest the southeastern corner of the intersection of the W&OD bike path with Old Reston Avenue one can find this white five-petaled flower with a prominent cone of five anthers and distinctly lobed long leaves.

This appears to be Carolina horsenettle (Solanum carolinense), which, despite the name, is not actually a nettle, but rather a nightshade, closely related to eggplant and a bit more distantly to tomato and potato.  Compare this Illinois description and this Connecticut write-up.

Earlier this afternoon I had encountered another clump of Carolina horsenettles along the path leading from the parking lot of 1801 Robert Fulton Drive to the W&OD bike path.  These plants are obviously further along in their development;  they have finished flowering, and their berries (rather like small grape tomatoes, no?) are starting to ripen.  Warning - these berries are quite toxic.

And now for an old standard - yes, of course there are dandelions (Taraxacum spp., most likely T. officinale) in Reston.  This one is found in the lawn on the south side of the W&OD bike path just east of its intersection with Old Reston Avenue.

And where one sees a dandelion flower, one also soon sees a dandelion parachute ball ("Pusteblume", or "blow flower", in German), which contains the dandelion seeds ready for wind dispersal - just like the thistle seeds with which we started this afternoon.