Tag Archives: bedrock terrace

Confession; Summer Bounty

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Eutrochium species (purple flowers) and Eupatorium species (buds on right), both on the canal’s edge where I can’t get close enough to determine which species

I hate to admit it, but I’ve been in a bit of a slump lately. I can’t seem to take pictures of anything worth posting and writing about. Possibly my head is still stuck in the Faroe Islands. My heart is, too.

Hibiscus laevis standing in the floodwaters

I’ve been out for a few short hikes this past week, though. Flooding on the Potomac has prevented me from checking the bedrock terraces, or from taking close-up pictures of halberd-leaved rose mallow (Hibiscus laevis), a perennial favorite that’s blooming now, but is also standing in water. Which won’t hurt it, by the way – that’s its habitat. Just makes it hard for me to shoot.

Swamp rosemallow (Malvaceae)

Also blooming, and a little harder to find in the Potomac Gorge, is crimson-eyed rosemallow, aka swamp rosemallow (Hibiscus moscheutos). I’ve seen the plants on that terrace and am itching to get back there. This photo was taken at lock 8 on the C&O Canal. The whole embankment where it’s growing has been slashed back, maybe in an attempt to take care of the invasive aliens, but sadly they destroyed some nice natives in the process, including a stand of wingstem that I liked to shoot every year because of easy access. But at least the rosemallow survived.

Wild potato vine (Convolvulaceae); similar flower to the rosemallow at first glance, but entirely different family

Elsewhere on the Potomac’s banks and nearby, I’ve seen:

Heteranthera dubia growing in a rain- and flood-fed pool on a bedrock terrace

Virginia water horehound (Lycopus virginicus)
white vervain (Verbena urticifolia)
goldenrods (Solidago species)
Carolina horsenettle (Solanum carolinense)
hairy wild petunia (Ruellia caroliniensis)
winged sumac (Rhus copallinum)
fogfruit (Phyla lanceolata)
sweet joe-pye weed (Eupatorium purpureum var. purpureum)
thin leaved-sunflower (Helianthus decapetalus)
various St. Johnsworts (Hypericum species)
wild potato vine (Ipomoea pandurata)
water willow (Justicia americana)

Lindernia dubia, a mudflat ephemeral

grassleaf mudplantain (Heteranthera dubia)
winged monkeyflower (Mimulus alatus)
Allegheny monkeyflower (Mimulus ringens)
false pimpernel (Lindernia dubia)
large-flowered leafcup (Smallanthus [really] uvedalia)
trumpetcreeper (Campsis radicans)
swamp milkweed (Asclepias incarnata)
Virginia dayflower (Commelina virginica).

Helianthus decapetalus

Not bad for the height of summer! More on that last plant soon.

Ribbet

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It tickles me that a bedrock terrace can maintain a pond, providing habitat for so many wetland plants. Only a few dozen feet away from that pond grow plants like big bluestem grass, that prefer much drier habitats.

And in between, there are low-growing swaths of fogfruit.

I’m not sure if technically fogfruit is a mudflat ephemeral, but the plants don’t seem to appear until river level drops, and then they pop up from the muddy shores, the rhizomes forming large mats of vegetation that stand about 12 to 18 inches tall.

Phyla lanceolata (formerly Lippia lanceolata) is in the Verbenaceae, a family of about 1,000 species in about 30 genera. Plants in this family can be found worldwide, but most of the species are tropical; P. lanceolata is one of the more northerly occurring ones. There are about a dozen species of Phyla, maybe half of which are native to North America. This one is found in much of the US, excepting New England, the northern Great Plains, and the Pacific Northwest. Populations seem to be concentrated in the Mid-West and along the Mississippi River corridor. It’s endangered in New Jersey and rare in Pennsylvania, and the only species of Phyla found in Maryland.

The inflorescence of fogfruit is fairly typical of plants in the Verbenaceae, the individual flowers clustered together in a tight spike. (It looks to me a lot like lantana, a common garden plant.) The individual flowers have five petals, fused together into a tube with irregularly spreading lobes. Many but not all of the flower clusters I’ve seen have this wonderful arrangement: yellow-throated flowers alternating with mauve-throated flowers.

About that common name… to some it’s “fogfruit”, to others it’s “frogfruit”. Wondering if the latter was a mispronunciation of the former, I was all set to do some real book research, but looked first on the internet, where I found, unsurprisingly, that it’s already been done:

In the end though, frogfruit with its alliterative cadence may simply be easier to say than fogfruit…

Either way, it’s a charming little thing.

Common Arrowhead

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The bedrock terrace I’ve been writing about supports a surprising number of wetland plants. This one, Sagittaria latifolia, is not only a wetland obligate, it’s an emergent: an aquatic plant that roots in shallow water and produces stems, leaves, and flowers above water level.

Typical of monocots, S. latifolia has floral parts in multiples of three, with three sepals and three petals. The flowers are typically unisexual, the male flowers having numerous yellow-anthered stamens, the females having numerous green pistils. In bisexual flowers, the stamens ring the pistils, as shown here. The flowers are usually borne on racemes, sometimes on panicles, with flowers in whorls.

Although S. latifolia is found in every state in the union except Nevada and Alaska, and in much of southern Canada, it’s most common in New England, the Mid-Atlantic, and the Upper Midwest. (It’s also in Hawaii, but considered alien there.) It’s endangered in Illinois, but considered weedy by the Southern Weed Science Society.

S. latifolia is in the Alismataceae, or water plantain family, which comprises anywhere from 80 to 120 species in about 15 genera, depending on which authority you consult. The Alismataceae is cosmopolitan, but most species are native to North America.

Common names include common arrowhead, wapato, wappata, and katniss. Some names refer to the plant’s appearance or habit: arrowleaf, bull-tongue, water-archer, water-lily, waxflower. Other names refer to edibility: Chinese-onion, duck-potato, muskrat-potato, swan-potato, swanroot, and tule potato.

Bewitched by Buttonbush

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As soon as I finished shooting swamp candles Tuesday morning, I turned my attention to a nearby buttonbush. The sunlight was no longer quite so golden, but it was still making great shadow play among the plants.

Cephalanthus occidentalis (Rubiaceae), also called buttonwillow, honeyball, and pond dogwood, ranges from Nova Scotia and Ontario south to Florida and Texas, and is also found in parts of Arizona and California. There are records of it in every Maryland county except Washington.

The multiple stems of this shrub can grow to about twelve feet tall, and the plant can be 6 feet across or more. Foliage is dense and a pleasing shade of green, and how can you not love that inflorescence?

The flower heads measure about one inch across and bear dozens (hundreds?) of flowers, each of which consists of four fused petals, four stamens, and one very long style.

The flowers attract butterflies and bees, and later in the season the seeds attract birds.

Buttonbush is a wetland obligate, meaning that in natural conditions it will be found in wetlands. But there are quite a few of them on the bedrock terrace, which is a dry place except for seasonal flooding and rains. There isn’t much soil there, and no groundwater.

 

Knowing this, I had assumed it wouldn’t make a good garden plant, but I asked the question on a native plant discussion site and got a lot of encouraging replies. It seems that once established, buttonbush does quite well in drier soils. Hooray! Now I just have to find a place for one in my garden.

Golden Glow

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this little pond is about 20 feet above the river; currently at least six species of plants are blooming around (and in) it.

 

Feeling down after a not-too successful photo shoot, Tuesday morning I headed back to one of my favorite spots, a bedrock terrace that has a wide array of summer-flowering plant species.

 

It was early enough that the rocks were casting deep shadows, and as I scrambled up and over them, the rising sun spilled gold onto this small stand of flowers. I visit that terrace often in the summer, but had no idea swamp candles were there!

There’s just no substitute for good light.

 

Lysimachia terrestris (Primulaceae) is one of about 15 species of Lysimachia in Maryland. Maybe half of those can be found in the Piedmont, and four of those are alien.

Lysimachia ciliata; shockingly I don’t have a newer (better) picture than this

 

More often I see fringed loosestrife (L. ciliata), a dainty thing often overlooked, since the flowers are nodding. It likes drier soils and maybe more shade than swamp candles.

Lysimachia quadrifolia

 

 

 

Another common one is whorled yellow loosestrife (L. quadrifolia). I saw lots these in June on Sideling Hill (the Ridge and Valley physiographic province), but there are records for it almost everywhere in the state. All of them were growing in deep shade.

 

 

For a native loosestrife, though, this species is exceptionally showy.

Swamp candles can be found primarily in New England, the mid-Atlantic, and the upper Midwest; they can also be found in scattered populations in parts of the South. They’re endangered in Kentucky and Tennessee.

 

As the common name suggests, they like having their feet wet. It’s a little unusual to find them in a place like this bedrock terrace; generally they’re along the banks of the Potomac, not as in-the-water as water willow, but close by, in areas that are probably under water early in the season, before river level drops. Nearby you might see monkeyflower, American germander, and halberd-leaved rosemallow; the first two are blooming now; the latter is just about to.