Spring Cress

Thanks to LW’s comment on my recent post about toothworts, I was finally able to see a good-sized stand of Cardamine bulbosa, also known as spring cress, bulbous bittercress, or bulbous toothwort.

This species is a wetland obligate; here you can see it almost standing in the water of a vernal pond.

 

The cauline (stem) leaves are entirely different from the slender and cut-leaved toothworts’.

 

 

The basal leaves are, too.

 

 

 

The flowers and inflorescence look much like the toothworts, though. Another Cardamine species found in Maryland, limestone bittercress (C. douglassii), is almost identical to spring cress, but it species has hairy, dark purple sepals rather than the smooth, green sepals seen here.

 

Spring cress is native to the eastern US, where it ranges from Florida to New Hampshire (where it’s endangered) and into the Great Plains from Texas to Minnesota.

Toothworts

Forest floors in the Maryland piedmont are carpeted now in spring ephemerals. Spring beauties are everywhere, Virginia bluebells and Dutchman’s breeches seem to be confined to wetter areas, and in drier areas, you’ll see toothworts.

Formerly placed in the genus Dentaria, toothworts are now lumped with the bittercresses in the genus Cardamine. The flowers are similar on close inspection but the overall difference in appearance between toothwort and bittercress plants is pretty obvious.

Older guidebooks frequently list two to five species of toothworts in the eastern US. Here’s a quick look at the names (it’s not my intent to provide a complete synonymy):

current name older name(s) common name(s)
Cardamine angustata Dentaria heterophylla slender toothwort

Cardamine concatenata

Dentaria laciniata
Dentaria concatenata
cut-leaf toothwort

Cardamine diphylla

Dentaria diphylla toothwort
broad-leaved toothwort crinkleroot

Cardamine dissecta

Dentaria dissecta
Dentaria multifida
fine-leaved toothwort
dissected toothwort
Cardamine maxima Dentaria maxima large toothwort

C. dissecta has a limited range, from Alabama northeast into West Virginia, and is endangered in Indiana. C. maxima seems to have disjunct populations in Kentucky, Wisconsin, Michigan, Pennsylvania, and a few parts of New England; it’s threatened in Michigan, endangered in New Jersey, and possibly extirpated in Maine. Neither of these species has been reported in Maryland.

C. diphylla is found in the Appalachian South, the mid-Atlantic, New England, and upper midwest, possibly with a few occurrences farther west, from Arkansas to Minnesota. MBP has only a few records in the piedmont, and a few more in the Appalachian Plateau. One of the records is of a sample in the Norton-Brown Herbarium; it was collected in 1974 “[o]ff beltway exit to Great Falls near Seno [sic] Canal”, which is right along the Potomac gorge and my usual hunting grounds. Maybe I have a new quarry to track?

C. angustata is a southeastern species, ranging from south-central Alabama north to central Indiana and northeast into Pennsylvania. In Maryland it seems to be found mostly in the piedmont.

C. concatenata is found mostly in the mid-Atlantic and mid-west and New England, though it does range into the South and the eastern Great Plains. It’s endangered in Maine and New Hampshire. It seems to be in most of Maryland except the far west and southern Eastern Shore.

The flowers of all of these toothworts are very similar in size, shape, and color, and can’t easily be used to distinguish between the species. It’s best to look at the leaves.

C. concatenata has no basal leaves present at blooming; on the stem is a single whorl of three leaves, each leaf palmately divided, with serrated leaflets. It’s worth noting that there seems to be a wide range of morphological variation: on some plants the leaflets are quite narrow, while on others they’re rather broad; on some plants there are three leaves in a whorl, but on other plants they might be sub-opposite, or there might be only two leaves.

Be that as it may, C. angustata is pretty easy to distinguish from C. concatenata. It has two alternate or sub-opposite stem leaves, each with three leaflets (usually) that are quite narrow and serrated to some degree. The basal leaf (sometimes leaves) is large, with very broad leaflets, on a very long petiole.

Another species worth mentioning is Cardamine bulbosa, commonly called spring cress or bulbous toothwort. Although it was never a Dentaria and is more often referred to as a bittercress than a toothwort, the flowers look toothwort-y. The species is found in most of the eastern US (and most of Maryland), but not in Maine, and it’s endangered in New Hampshire.

Compressed (part 2)

Here are some of the showier spring ephemerals to watch for in the Potomac Gorge this week.

In the floodplain close to the river, Virginia bluebells (Mertensia virginica; left) are approaching peak bloom. Mixed in with them in a few places are Dutchman’s breeches (Dicentra cucullaria; below right), which you might also find on moist, rocky outcroppings.

Trout lilies (Erythronium americanum; above left) like moist soils, too. Generally I see them in the transition areas between floodplain and slopes.

Further upslope are cut-leaf toothworts (Cardamine concatenata; left).

 

On drier slopes watch for scattered patches of bloodroot (Sanguinaria canadensis; below).

 

 

Look for twinleaf (Jeffersonia diphylla; below) in moist, rocky areas. They like limestone soils, so aren’t as widespread as these other species, but where they do grow they they tend to grow en masse.

Spring beauties (Claytonia virginica; below) are just about everywhere.

 

 

 

 

More tomorrow.

But First, a Quick Update

I went scouting on the Billy Goat C Trail Monday. Harbinger -of-spring is still blooming. More spring beauties are blooming.

Just a few Dutchman’s breeches are open.

 

 

 

 

As are cut-leaf toothwort.

 

 

 

 

And just a few golden ragwort.

 

 

 

 

Virginia bluebells are budding up nicely. A few more days of warm weather and the ephemerals show will be underway.

On the Last Day of Winter

Today is the first day of meteorological spring* (astronomical spring is still three weeks away), but as of yesterday, the 28th of February, the wildflower show had already begun along the Potomac. Barely.

Claytonia virginica (spring beauty; Montiaceae)

Just a few dozen of these were up in sheltered locations.

This one specimen of Packera aurea (golden ragwort; Asteraceae) already had well-developed buds. Often this species will retain leaves through the winter, and many low-lying leaves were visible, but I saw none of the tall growth yet. In the same location last year just a few flowers were open on March 23, with peak bloom about April 13; in 2015, I saw the first ones March 24, with peak bloom in mid-April.

Erigenia bulbosa (harbinger-of-spring; Apiaceae)

More about this in an upcoming post. Can you see it sheltering there under the maple leaf? That’s one plant with about 14 flowers!

A few alien species are starting to bloom: Veronica hederifolia (ivy-leaved speedwell) and Cardamine hirsuta (hairy bittercress).

And, I saw one clump of Mertensia virginica (Virginia bluebells) foliage emerging, but that makes a boring photo.

*more on meteorological seasons from NOAA

Teaser

The earliest ephemerals are out and blooming a few hundred miles away, in South Carolina, but it’ll be a few more weeks before they start blooming here in the mid-Atlantic. Here’s a sneak preview of what’s to come, presented more or less in the order in which they bloom. All of these should be blooming by the end of March at the latest.

Erigenia bulbosa (harbinger-of-spring, pepper and salt; Apiaceae)

One of the first up, sometimes as early as late February. Look for it in moist woods but you have to be eagle-eyed to spot it (note the dime sitting there for scale). Just as I was finishing this post, a friend reported seeing harbinger blooming here in the Maryland Piedmont today!

Anemone americana (round-lobe hepatica; Ranunculaceae)

A hibernal plant; the leaves usually wither away by the time the flowers bloom, or soon after. If you see the leaves now, note the location and check back in a few weeks for the flowers.

 

 

Lindera benzoin (spicebush; Lauraceae)

Don’t forget to look up once in awhile! This very common understory shrub is one of the first plants to bloom in our area.

 

Arabidopsis lyrata (lyre-leaved rockcress; Brassicaceae)

This plant has a long bloom period, often starting early in the season. Look for it growing right on large rocks, as the common name suggests. The sight of a mass of these delicate blossoms dancing in even the slightest breeze fills me with joy.

Cardamine concatenata (cut-leaf toothwort; Brassicaceae)

Such a dainty thing.

 

 

 

Corydalis flavula (short-spurred corydalis and many other common names; Papaveraceae)

Another petite flower, easy to miss. You have to get very close to see all the ornate details.

 

Micranthes virginiensis (early saxifrage; Saxifragaceae)

This fine specimen is one of the largest I’ve seen. I usually find them in rocky places.

 

Dicentra canadensis (squirrel corn; Papaveraceae)

The delicate, lacy, ferny foliage is almost identical to that of Dutchman’s breeches; you have to see the plants flowering to tell them apart with confidence.

 

Dicentra cucullaria (Dutchman’s breeches; Papaveraceae)

From my limited observation, this species is usually waning when squirrel corn is just getting started. There’s a hillside on the Cabin John Trail that’s covered in these plants.

Next time, more teasers.

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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