Hieracium venosum and Senecio aureus; Asteraceae (aster family)

In late March or early April the distinctively veined basal leaves of rattlesnake weed start emerging on rocky bluffs and drier soils along the Potomac:

 A month or so later the long stems start bearing the flowers:

  You’ll find rattlesnake weed growing alongside azure bluets and plantain-leaved pussytoes.

At about the same time, maybe a week earlier, golden ragwort will be in bud:

 Note how the basal leaves and stem leaves are entirely different from each other.  Its peak flowering will be well before rattlesnake weed’s.

Golden ragwort likes the wetter soils closer to the river.  You can find it on the eastern half of Billy Goat C.  Rattlesnake weed will be on the western half, near Carderock.

According to the USDA PLANTS database (plants.usda.gov), there are eight species of dogwood and ten of viburnum to be found in this area.  All have opposite, simple leaves (except the pagoda dogwood, which has alternate leaves).  All are small to medium sized understory trees or shrubs.  Some species have distinctive leaves,

Viburnum acerfolium (maple-leaved viburnum)

but most have very similar leaf shapes.  The dogwood leaves have different venation from the viburnums.

At first glance viburnum and dogwood flower clusters look alike, but the flowers themselves are quite different.

Viburnum dentatum (southern arrowood)

Viburnum prunifolium (blackhaw)

By the way, the blossom of the ubiquitous flowering dogwood (Cornus florida) is not actually a flower; those four showy petals are bracts, surrounding the tiny flowers in the center.  (A bract is a modified leaf that looks like a flower.)

 Cornus alternifolia (pagoda dogwood)

Viburnums are in the Caprifoliaceae (honeysuckle family), while dogwoods are in the Cornaceae (dogwood family).  Despite the apparent similarities, you have to go a few steps up the taxonomic ladder to find the common relation (which is the class Magnoliopsida, dicotyledons).

Mitchella repens; Rubiaceae (madder family)

As you may have gathered, I’m particularly fond of tiny flowers, and flowers that hide, and small plants.  And rocks.  And lichens.

Two days ago I went straight from the car to a huge patch of partridgeberry growing atop some rocks near Carderock, hoping to find it blooming. I was not disappointed.

Partirdgeberry is a very low-growing plant (one inch tall) with evergreen leaves about the size of a pinkie nail.  It seems to prefer growing in slight amounts of soil on top of rocks, and can trail along or off the rocks for several feet.  It always blooms in pairs.  If both flowers are pollinated, they will fuse together to form a single fruit.  This picture shows almost everything: two pairs of buds, one pair of flowers, and two pairs of flowers starting to fuse:

Would you believe I spent more than 15 minutes taking more than 50 pictures of this plant?

When I started cataloguing my finds, the question quickly arose: do I count everything?  Even weeds?  Even trees?  The answer was yes (mostly; I don’t log white clover or dandelions).  Of course trees.  Oaks and maples don’t have the most interesting flowers, but some tree flowers are just spectacular.  Here are two.

tulip poplar  Liriodendron tulipifera; Magnoliaceae (magnolia family)

This tree typically gets up to 150′ tall, though occasionally up to 200′, and is one of the tallest trees in the eastern US.  The flower is several inches across.  It’s easy to see the resemblance to the magnolias.

northern catalpa Catalpa speciosa; Bignoniaceae (trumpet-creeper family)

Northern catalpa grow only about half the size of tulip poplar (rarely up to 100 feet), but the large clusters of fragrant flowers are spectacular.  The leaves can be 12 inches long.  Although it’s listed by the USDA as potentially invasive, there don’t seem to be many specimens in this area.

Scutellaria nervosa; Lamicaeae (mint family)

And we’re back to blue flowers.

I’m always so excited to trip across something new.  There are at least six species of skullcaps to be found in this area, with bloom times varying from late spring to early fall.  Last year I found hairy skullcap.  This year I’ll also be searching for downy, little, showy, and mad-dog skullcaps.

The plants stand up to two feet tall; depending on which authority you consult, the flower size ranges from 1/8″ to 1/3″.  The ones pictured here were about 1/8″. They occur singly in the leaf axils (therefore two flowers per node), hiding below the leaves.

Lighting and wind conditions were such that I could not get a good-quality extreme closeup.  There wasn’t a way to set up a sandbag.  A tripod might have helped.  Back to the toystore…