Slope Fen, Cape Breton Highlands


Looks like a grassland at the edge of the boreal forest, doesn’t it?  Actually, it’s a slope fen; there’s water flowing very, very slowly under there.  You can’t walk across it, but there is a boardwalk around it.  There are a few open pools of water within.


So you might be wondering, as I did, what distinguishes a fen from a bog, or from any other type of wetland?  And what exactly is a wetland?

According to Lewis Cowardin of the US Fish and Wildlife Service, “wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface (December 1979).”

There are four main types of wetlands: marshes, swamps, bogs, and fens.

Marshes are wetlands dominated by herbaceous vegetation.  Most of the water in marshes comes from the surface, but in many cases groundwater is also a source.

Swamps are wetlands dominated by woody vegetation.  There are a few swamps on the Maryland side of the Potomac gorge.  Long-tube valerian, winged monkey flower, and lizard’s tail are some of the wildflowers I’ve found there.

Bogs are wetlands formed by the growth of sphagnum moss either over a pond, filling it in, or over land, preventing water from evaporating.  Either process results in a wetland characterized by very acidic water and a low amount of nutrients.  Not many plants are well adapted to these conditions.  Regardless, the bottom of a bog is generally impermeable, so most of a bog’s water comes from precipitation.

A fen is basically a bog that receives some groundwater; as a result, fens have more nutrients and less acidic water.  They support a broader range of plants than bogs do.

Bogs and fens are found mostly in the higher latitudes of the northern hemisphere, and in some alpine areas in the middle latitudes.  There are no bogs or fens in the Potomac gorge.


A slope fen is exactly what you’d think it is: a fen situated on  gently sloping land. Sadly I did not learn the names of most of the plants I found here, though I believe the area is dominated by rushes, not grasses.  (Hmm, now I have an idea for another blog post.) 20140915-DSC_0200

If you click on the first picture and zoom in, you’ll see some goldenrods and a northern pitcher plant.

In case you were wondering, the sevenangle pipewort featured on November 26 was found in the shallows of a very large pond, not in this slope fen.


Flower of the Day: Canadian Burnet

Sanguisorba canadensis; Rosaceae (rose family)


First, an apology – the picture above is a little misleading.  The green branches behind the inflorescences are balsam fir, which makes for a poor photo illustration.  Sometimes I don’t have much of a choice, though.

The presence of balsam fir should be a clue that once again, I’m cheating.  I found this plant in Nova Scotia, and didn’t pause long enough for a proper photo shoot.  Here’s a look at the leaves:


Canadian Burnet is native to the eastern US and Canada and the Pacific Northwest.  Though it does occur in Maryland, it is probably not a plant of the Potomac gorge; I’ve found references to it growing in Baltimore County and in the Blue Ridge, and west of there.  Sadly it is either threatened or endangered in nine states, including Maryland.

Burnet is a perennial that likes a wet habitat, though it is fairly drought resistant.  It will grow up to five feet tall.  Four other species (three native, one alien) of Sanguisorba are found in North America.


In the past burnet sap was used to staunch wounds.  The genus name comes from Latin words meaning “blood” and “to suck in” (presumably that’s also the root of the word “absorb”).

Flower of the Day: Sevenangle Pipewort

aka common pipewort; Eriocaulon aquaticum; Eriocaulaceae (pipewort family)


I’m cheating again.  Found these plants at the edge of a pond in Nova Scotia. According to the USDA, sevenangle pipewort can be found in Maryland – in Anne Arundel county – and in the District of Columbia, and Fairfax County, Virginia. The Maryland Biodiversity Project lists it in several Eastern Shore and northeastern counties.  So it could be in the Potomac gorge.  Next year I’m hunting for it.

Sevenangle pipewort is endangered in Indiana and Ohio as well as in Maryland. It ranges as far south as North Carolina, west to Minnesota, north into Manitoba, and all the way east to the Atlantic Ocean.

It’s aquatic: all the leaves grow underwater, and a single hollow (hence pipewort), multi-ribbed (hence sevenangle) stem emerges from the water to support the flower head.

There are other pipeworts, including tenangle and flattened, in the eastern US, about a dozen across North America, and more than 400 species worldwide.


Flower of the Day: Bunchberry


Cornus canadensis; Cornaceae (dogwood family)

Now I’m cheating.  According to the USDA, bunchberry can be found in Maryland.  But it’s a northern plant that doesn’t like the heat and humidity of mid-Atlantic piedmont summers (I should know, I’ve tried growing it often enough), so you won’t find it in the Potomac gorge.  You might be able to find it in the westernmost part of the state (Garrett County), at the higher elevations. Or maybe not; it’s endangered there, as well as in Indiana and Illinois.  And it’s threatened in Iowa and Ohio.

This one I found on Cape Breton Island, Nova Scotia, in September (very unusual for it to be blooming so late in the year), in the boreal forest region.

Really looks like our common flowering dogwood (Cornus florida), doesn’t it? But it isn’t a tree or shrub; it’s a groundcover, standing less than a foot high.