Afternoon of October 22, 2009 (continued)

On the south side of the W&OD bike path, just east of its intersection with Michael Faraday Drive, and hidden among the mile-a-minute vines that are now dying back, is this full-in-fruit shrub, which appears to me to be a viburnum.  More specifically, this might be a wayfaring bush (Viburnum lantana), based on the red color of the fruit on their terminal clusters (we have not had our first autumn frost yet) and the rather narrow shape of the leaves.  Compare the Virginia Tech fact sheet and this page from Washington State University, which, however, shows rather broader leaves.

As one enters the oak-hickory forest of Lake Fairfax Park on the path that extends north from Michael Faraday Drive, one soon encounters mossy patches.  Here is an extreme close-up, which  shows that the moss patch is more than just velvety green;  there is actual structure, with branched stems.  I have to admit that I have no idea about the proper classification of this organism;  I am not even sure whether it is a true moss (division Bryophyta) or a spikemoss (genus Selaginella).  Lots of room for further education here!

O.k., back to vascular plants.  This specimen is on the south side of the Reston Association path from Tall Oaks shopping center just before it crosses North Shore Drive south of the Golf Course Island pool.  This is clearly a smartweed (Persicaria spp.) of some kind, but I am not sure about the species.  Note the dark splotch in the center of one of the leaves;  this would support identification as Lady's thumb (Persicaria maculosa), but the sheath around the leave nodes is not fringed.  Other possibilities are pinkweed (Persicaria pensylvanica) or pale smartweed (Persicaria lapathifolia).

A close-up of the inflorescence.  Compare to these Washington state pages on pale smartweed and Lady's thumb and this Illinois description of pinkweed (which, in this particular case, has white rather than pink flowers).  Whatever it turns out to be, it is not uncommon in Reston;  I have also encountered this plant in various shaded places along the W&OD bike path.

In the "underbrush" of the grass at this location one can also find this particular grass species, with its very distinctive radiating spikes lined with two rows of spikelets.

The parallel rows of close-fitting spikelets are particularly apparent when viewed from above.  Based on Lauren Brown's Grasses: An Identification Guide, this appears to be goose grass (Eleusine indica), which is a weed of disturbed urban areas.  Compare this excellent description from Illinois.

Towering over both the smartweed and the goose grass at this location is this graceful grass with its purple spikelets.

A close-up look shows that the ligule (where the sheath of the leaf meets the culm, or stem) is not very prominent, with perhaps just a hint of some hair.

Another overview shot to show how tall this grass is.  Based upon its height, late blooming, purple seedhead coloring, broad leaves, and lack of prominent ligule, I believe this may be purpletop grass (Tridens flavus);  compare this Illinois description and this Kansas description.

Added by edit August 7, 2010:  now that I have more experience looking at grasses, this identification is clearly wrong.  Yes, we have Tridens flavus in Reston, but it is generally smaller, and the leaves are not as prominently keeled.  Instead, this is a johnsongrass (Sorghum halepense, see this Missouri description and this photo gallery).  The prominently veined leaves are very similar to those of Eastern gamagrass, so these two species cannot be distinguished until the very different inflorescences mature.

Turning once again to trees, there is this spectacular ornamental tree in the open area at the center of the Golf Course Island cluster (south of Cypress Point Court, east of Torrey Pines Court, and west of the Golf Course Island pool).

In this picture (actually taken from a berm standing above the branch), one can clearly see that the needles are arranged in whorls - very different from the spruces and pines seen earlier this afternoon.  This whorled pattern indicates that this is a true cedar (Cedrus spp.), and the whitish-blue color of the needles suggests that this is an Atlantic cedar (Cedrus atlantica), cultivar "glauca".  Compare the Virginia Tech fact sheet.  This is closely related to the Cedar of Lebanon (C. libani), the biblical cedar from whose wood King Solomon built the first temple.

Some of the lower branches sport cones like this one.  These are the male cones, which apparently have recently released their pollen;  the female cones, just as in other species of the pine family, tend to be higher up in the tree and thus out of range for my camera.  Compare the third entry on this Hawaii guide to pine family trees.

Finally, another close-up to show that, while most hollies (Ilex spp.) are now sporting their red berries, this one, on the walk-way between Charter Oak Court and the Charter Oak town house development, is just now bursting into flower.

Afternoon of October 22, 2009

Right next to the ornamental crabapple trees at the entrance to the parking lot at 1801 Robert Fulton Drive (shown in this posting) is this line of beautiful ornamental conifers - very much the traditional Tannenbaum of my childhood Christmases in Germany.

Given the four-square, rather stiff needles and the fact that the cones are hanging rather than standing erect on the branches, this is very clearly a spruce (Picea spp.) rather than a fir.  Because the branches do not droop, and the foliage (especially this year's new growth) is rather blue in color, I believe this is a blue spruce (Picea pungens).  See the Virginia Tech fact sheet.

The cones tend to be concentrated in the top portion of the tree and can be quite abundant, as seen in this specimen, which is located down the street from the one shown in the first photo and is lighted differently (the tree in the background is an oak).

The blue spruce can be compared with this spruce located in the Charter Oak townhouse development.  Note the drooping branchlets (also note the rather scraggly outline of the tree;  this and all other spruces in the townhouse development were recently pruned).  This is a Norway spruce (Picea abies).  Compare the Virginia Tech fact sheet.

A closer look at the Norway spruce, demonstrating that it is in fact a spruce (note the hanging rather than erect cones) and also suggesting that the cones are rather more elongated than the ones of the blue spruce.

Back on the W&OD bike path, clear evidence that botanical classification actually makes sense!  Thoroughworts (Eupatorium spp.) are members of the Asteraceae family, and thus, just like the thistles, dandelions, and goldenrods that are also classified in this family, the thoroughworts (like this one just south of the Dulles Toll Road bridge) develop white balls of tufted hair to carry off seeds in the wind once flowering has finished.

Another sight of beauty, this one on the north side of the W&OD gravel path at the top of the hill east of Michael Faraday Drive - a wild eastern redcedar (Juniperus virginiana), in full fruit.

Here is a closer look at some of the bluish-white berry-like cones, as well as the four-square branchlets covered in tightly-layered scale-like needles.

Just down the hill, in the northeastern corner of the intersection of the W&OD gravel path with Michael Faraday Drive, is this fascinating pine.  Note the very sharp spike at the end of each cone scale (the cone is quite prickly to the touch).  In this image, you can also see one or two seeds still clinging to the inside of some of the cone scales, especially in the upper right portion of the front cone - the scales themselves are not the trees progeny, but rather the pair of seeds sheltered by each scale.  Also note that the needles are relatively short and come in bundles of two.

On the tree you can find not only this year's new cones, but also quite ancient cones still attached to the tree - this is a pine that does not drop its cones.

In fact, some cones have remained attached for so long that all the scales have been stripped off, leaving just the bare core of the cone hanging on the branch!

Thus, when looking up into this tree, one is struck by the large number of dead cones still remaining.  Based on all of these criteria, this pine, according to Charles Williams's "The Pines of Virginia" (available here), is a Virginia pine or scrub pine (Pinus virginiana).  Also compare the Virginia Tech fact sheet.  This species is an early colonizer of abandoned fields;  thus, it makes sense to find it here along the abandoned railroad.

Compare the Virginia pine with the eastern white pine (Pinus strobus), shown here in a specimen from the north side of North Shore Drive near the Charter Oak townhouse development but very frequently encountered everywhere in Reston.  The eastern white pine has rather longer needles that are in bundles of five;  its cones are also larger, more elongated, and lacking a spine, and they drop after two years.  See the Virginia Tech fact sheet.

Afternoon of October 20, 2009 (continued)

This tree is found on the south side of Fairway Drive just east of its intersection with Greenbriar Court.  It is a yew (Taxus spp.).  According to Melanie Choukas-Bradley's City of Trees, the most common yew found in our area is the English yew (Taxus baccata);  compare the Virginia Tech fact sheet.  However, it could also possibly be a Japanese yew (T. cuspidata;  compare the Virginia Tech fact sheet) or a hybrid between the two.

A close-up of the fruit, which is a naked seed (after all, this is a gymnosperm, or "naked seed" plant) surrounded by a fleshy red aril.

A goldenrod (Solidago spp.) gone to seed, with white hairy tufts emanating from the seeds, ready to carry them off.  Note that goldenrods, like dandelions and thistles, belong to the Asteraceae family;  all three genera have seeds that are dispersed by the wind through white hairy tufts.

This tree, and another one like it, are found on the southwestern corner of the intersection of Fairway Drive with North Shore Drive.  It is a Japanese pagoda tree, also known as a Chinese scholar tree (Styphnolobium japonicum), which is native of China rather than of Japan.  Compare the Virginia Tech fact sheet and this Wikipedia page.

The long seed pods that look like a string of pearls are very much in evidence now.  These pods also remind us that this plant is a member of the Fabaceae family, which also includes beans, peas, and other pod-bearing legumes.

Afternoon of October 20, 2009

More red berries!  This shrub is located on the north side of the Reston Assocation path that crosses underneath Wiehle Ave just south of its southern intersection with North Shore Drive.  This location is west of Wiehle Ave and south of the end of Putter Lane.

A closer look at some of the berries.  Note the serrated leaf edges, the opposite arrangement of the leaves (more noticeable in the previous image), the prominent veining, and the fuzz on the twigs bearing the red berries.  This appears to me to be a viburnum, and more specifically a linden viburnum (Viburnum dilatatum).  Compare the Virginia Tech fact sheet.

On the west side of Wiehle Avenue just north of its southern intersection with North Shore Drive is this clump of bamboo (with a young holly shrub in the foreground).

A closer look into the bamboo patch, with one of the characteristically jointed bamboo "poles" (stems or culms) visible in the background.  I have found it difficult finding definitive taxonomic guidance on the various bamboo species;  however, it appears that the most commonly invasive bamboo in Fairfax County is golden bamboo (Phyllostachys aurea).  See this indictment.  Reston's list of 8 forbidden species merely lists "exotic bamboo", without specifying the species.

Now for a more pleasant exotic species.  This tree, with its spectacular symmetric cone shape, is found at the end of the first cul-de-sac on the south side of Fairway Drive west of Wiehle Avenue.

Note the delicate and lusciously green needles that form two ranks and are arranged like a bipinnately compound leaf.  These needles are in fact deciduous, and the tree is dawn redwood (Metasequoia glyptostroboides).  Compare the Virginia Tech fact sheet, as well as this Wikipedia article and this information on a North Carolina plantation.

Male cones hanging in stringers from the end of the branches.  I find it fascinating that this species was unknown until found in the 1940s surviving in one isolated forest in Sichuan province, China, and from there has been propagated across both China and the U.S. over the past 60 years, thereby ensuring its survival (closely related but now extinct species dominated North American forest covers 10 million years ago, and somewhat more distantly related species are the coastal redwood and giant sequoia of California and the bald cypress).

The base of the trunk of this tree, with both dark green English ivy (Hedera helix - one of Reston's 8 prohibited species;  compare the Virginia Tech fact sheet) and lighter green Virginia creeper (Parthenocissus quinquefolia) ascending.

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.