The Spring Ephemerals, part 3

Well, I’ve made the decision: no wildflower hunting for the foreseeable future. You can imagine how sad this makes me. But people just aren’t being careful about social distancing, and there isn’t enough open space for everyone who insists on going out.

In the meantime, I’ll follow the season by posting old pictures.

If I were being strictly chronological, harbinger-of spring (Erigenia bulbosa; Apiaceae) would have been the first plant in this series of posts.  It’s almost certainly done blooming by now.

These little plants bedevil me: they grow only a few inches tall, the individual flowers are tiny (notice the oak leaf in the picture below), and they’re so dainty that they’re always in motion, so they’re tricky to photograph. I do love trying, though.

 

 

Another one that’s never still is lyre-leaved rockcress (Arabidopsis lyrata; Brassicaceae). Growing right out of small depressions in rocks, these plants stand just a few inches taller than harbinger of spring. Look how slender those stems are compared to the pine needles lying nearby. I’ve seen stands of these blooming as late in the season as early June.

Here’s another diminutive plant that grows in moist, rocky areas: early saxifrage (Micranthes virginiensis, formerly Saxifraga virginiensis; Saxifragaceae). Its blooming period can start as early as late March and last through early May.

Evening Dowagers

Hesperis matronalis, right there on the trail

On the Billy Goat B Trail near the Marsden Tract, about ten days ago, there was a great stand of tall plants blooming in various shades of purple. In past years other hikers have asked me if I knew what the plants are. They’re so beautiful and eye-catching!

four-petaled flowers of Hesperis matronalis

 

 

And, guess what? As is too often the case with showy flowers, this species is an alien invasive. Its common name is dame’s rocket; the botanical name is Hesperis matronalis. The four-petaled flowers are typical of plants in the mustard family (Brassicaceae).

Phlox divaricata

 

Beginning wildflower enthusiasts sometimes mistake dame’s rocket for our native wild blue phlox (Phlox divaricata), which has flowers in a similar range of colors. However, wild blue phlox is usually done blooming by the time dame’s rocket is starting.

alternate leaves with serrated margins on Hesperis matronalis

 

 

Also, the phlox is a shorter plant and has opposite leaves with entire margins, whereas dame’s rocket has alternate leaves with serrated margins.

range of colors in a stand of Hesperis matronalis

 

 

 

Dame’s rocket ranges through almost all of Canada and the US, except for the southernmost tier of states. It’s listed in Colorado as a noxious weed; is invasive, banned in Connecticut; and is prohibited in Massachusetts. The Missouri Botanical Garden website says, in bold red letters:

This plant is listed as an exotic invasive species to Missouri and the Midwest by the Midwest Invasive Plant Network. The species should not be planted in the Midwest.

It shouldn’t be planted in Maryland, either. It self-seeds like crazy. Come to think of it, wild blue phlox would make a wonderful substitute in the home garden. Unless you have rabbits. The rabbits destroyed mine within two days of planting last spring.

a single Hesperis matronalis on the other side of the trail

The generic name Hesperis is from the Greek word for evening, in reference to the pleasant fragrance the plants give at dusk.

 

Lovely Brassicas

Sometimes I trip across a passage that says something perfectly (or better than I could). So I’ll let botanist Chris Mattrick of the USDA Forest Service say it for me:

Members of the mustard family (Brassicaceae) are widely known for their taste, utility, and ability to become weedy, but rarely for their beauty.

After I’d written most of the previous post I realized that most of the brassicas I’ve seen in the Maryland piedmont are pretty weedy, with insignificant flowers.  But there are lovely ones as well.

For most of these plants, I’ve given the older botanical names as well as the current ones, since the older names often pop up in web searches and are in some of the classic wildflower ID books.

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Boechera laevigata (formerly Arabis laevigata)
Smooth rock cress is found in rocky areas in deciduous woodlands, primarily in the midwest, Appalachians and New England. It’s threatened in Massachusetts and Maine. The plant is a biennial, growing a basal rosette in the first year, with a raceme of small flowers in the second year. The flowers don’t open up much, making them inconspicuous. Mostly you’ll see the green sepals, with the tips of the white petals just peeking through.


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Arabidopsis lyrata
(formerly Arabis lyrata)
Lyre-leaved rock cress or sand cress is biennial or perennial with a wide range, including the Appalachians, New England except New Hampshire and Maine, the upper Midwest, much of Canada except Maritime Provinces, and Alaska. It’s endangered in Massachusetts and threatened in Ohio and Vermont. Look for it in sandy or rocky, dry to moist soils. The basal rosette of leaves is small, and the raceme slender, giving the impression of dainty white blossoms hovering over the ground. In the Potomac gorge, I see them growing right on top of rocks.

 


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Cardamine concatenata (formerly Dentaria laciniata)
I think for many people in this area cut-leaved toothwort, also known as pepper root, is one of the highlights of spring. This species is a spring ephemeral, emerging from the ground, leafing out, flowering and dying back all in the space of four or five weeks. It’s found in the eastern half of the US and Canada, mostly in the midwest, mid-Atlantic, and New England; it’s endangered in New Hampshire and Maine. There are many species of toothwort, but this one is easily identified by the whorl of three palmately compound leaves on the flowering stem. The flowers can be pure white or have some pink or purple blush to them. Look for them in rich moist woodlands in April.


slender toothwort closeup

Cardamine angustata (formerly Dentaria heterophylla)
About the time cut-leaved toothwort is fading, slender toothwort will be starting to bloom. The flowers are almost identical to cut-leaved toothwort, but the two species are easily distinguished by the leaves. Slender toothwort will have two leaves at the node rather than three; these leaves are palmately compound with exceedingly narrow leaflets. The plant also puts out a wide basal leaf whose petiole is so long, you might not realize it’s part of the same plant. Slender toothwort’s range is fairly limited: it’s found mostly in parts of the south, midwest, and mid Atlantic. There are no conservation issues. Another note about trying to distinguish these two species: I’ve found many cut-leaved toothworts with only two leaves instead of three. Whether this is a response to environmental stress, or genetic, or whatever, I don’t know, but the shape and cut of the leaf doesn’t change. So if you see a plant with only one or two leaves any they look like they belong to cut-leaved toothwort, that’s what it is.


Cardamine bulbosa
Spring cress, aka bulbous toothwort, has a very similar inflorescence to the previous two species, but the basal lives are simple rather than compound and tend to be round, while the stem leaves are simple and oblong. Also, spring cress grows in moist to wet soils in some sunlight (eg, open woodlands), a slightly different habitat. It ranges from the midwest to the mid-Atlantic and somewhat into new England. It’s endangered in New Hampshire.


 

Cardamine pratensis
This circumboreal species is known as both cuckoo flower and lady’s smock. And in some areas, meadow cress and bitter cress. Maryland Biodiversity Project has records for it in a few counties, but as I wrote a few months ago the taxonomy of this group of plants is still unsettled. At any rate, the flowers shown here were photographed in Iceland. My ID could be wrong, and I regret not having good pictures of the leaves, but this is what the flowers look like. I’ve never come across it in Maryland, where it’s listed as S1, highly state rare. It likes moist to wet soils in shady areas.

Hrafnaklukka: Cuckoo Flower, Indeed!

Cardamine species
Icelandic: hrafnaklukka
Brassicaceae

 

The flowers pictured here are easily identifiable as a Cardamine species. In the Maryland Piedmont, we have about 10 species of Cardamine, a handful of which have flowers very similar to what’s pictured. We call them “toothwort”, and the various species are readily identified by differences in their leaves.

Not so with this one. Almost as soon as I started trying to identify these I ended up in a taxonomic whirlpool.

A Guide to the Flowering Plants and Ferns of Iceland shows one species with flowers like this, and calls it Cardamine pratensis ssp. angustifolia. The listing Cardamine nymanii in the index goes to the same plant. Are the names synonyms? The book doesn’t say.

The Integrated Taxonomic Information Service accepts both C. pratensis and C. nymanii, but does not accept C. pratensis ssp. angustifolia, which it considers a synonym for C. nymanii.

The Botanical Map of Iceland shows a similar-looking plant and labels it C. nymanni.

The Natural History of Iceland website shows only C. nymanii.

In English one of these is called cuckoo flower, and the other is lady’s smock. Both have the same common name in Icelandic: hrafnaklukka.

I had to go to Svalbard to get an answer. Not literally, of course (I wish!), and only an answer, not the answer. The comments section of the listing for C. pratensis ssp. angustifolia on the svalbardflora.no website says “The Cardamine pratensis group is unusually complicated taxonomically.” It goes into a rather interesting discussion (interesting if you’re into that sort of thing) about the taxonomic difficulties and distribution of the similar species.

But hey, useful ID tips from the same site:

Cardamine nymanii is distinguished by, e.g., the glabrous, entire, fleshy leaflets with impressed veins. In the two others, the leaflets are often hairy, dentate, thin, and with protruding veins. Cardamine nymanii is distinguished from C. pratensisalso by the often distinct petiolules of leaflets on stem leaves (in common with C. dentata but absent from C. pratensis).

Well, guess what? I don’t have good enough pictures of the leaves. The ones I do have definitely show glabrous (smooth), entire (not toothed or lobed), fleshy leaflets, but they don’t have distinct petiolules (leaflet stems).

Gah! So what species did I find? I really can’t say.

Maybe I should just dub them “Icelandic toothwort” and add to the confusion.

Whatever species they end up being, they’re fairly common throughout Iceland, found almost everywhere except in parts of the highlands. I saw them blooming on Mt. Esja and in several places around Ísafjörður in the Westfjords.

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Variations on a Theme: Rockcresses

The taxonomists are at it again.  Most of the guide books still classify the rock cresses in the genus Arabis, but recently most New World species have been moved to either Boechera or Arabidopsis.

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lyre-leaved rockcress, aka sandcress (Arabidopsis lyrata, formerly Arabis lyrata)

 

 

 

Lyre-leaved rockcress is a mostly northern species, found across Canada and the northeastern US, with small, isolated populations found further to the south. It’s endangered in Massachusetts, and threatened in Ohio and Vermont

Needing very little soil, it doesn’t tolerate competition from other plants, but will grow happily by itself right out of rocks.

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smooth rockcress (Boechera laevigata, formerly Arabis laevigata)

 

 

 

Smooth rockcress seems to enjoy a little more soil than lyre-leaved; it can be found in rocky woods and ledges, but seldom growing right out of the rock.  It ranges from Quebec south to Georgia, and west into some of the Great Plains states, and is threatened in Maine and Massachusetts.

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The rockcresses are in the Brassicaceae (mustard family).