Please Rain; More Spring Ephemerals

River levels have been pretty high, and the vernal ponds are more full than I’ve seen them in several years, but I suspect the groundwater level is still pretty low. We need rain.

Or it may be that I need rain. With this compressed season, I’ve been out almost every day shooting, which means I have a backlog of several hundred photos to process and many ideas for blog posts to write. But those things won’t happen until the weather forces me to stay inside.

Micranthes virginiana (early saxifrage)

The initial tide of spring ephemerals is ebbing: while early saxifrage, golden ragwort, and toadshade are near their peak, Virginia bluebells, toothworts, Dutchman’s breeches and squirrel corn are all past theirs, and it looks like bloodroot, trout lily, and harbinger of spring are done. Round-lobe hepatica seems to be done near the Potomac, but is still going strong up at Rachel Carson Conservation Park.

Obolaria virginica (pennywort)

And speaking of RCCP, pennywort is blooming there now, and the pinxter azaleas are well in bud.

 

 

The second wave of spring flowers is well under way in the greater Carderock area.

Houstonia caerulea (azure bluets)

Recently I’ve spotted blue, yellow, and white violet species, sessile bellwort, yellow corydalis, azure bluets, and wild pinks.

 

 

Phlox divaricata (wild blue phlox)

 

 

Wild blue phlox is close to peak, and so is rue anemone.

 

 

 

 

Geranium maculatum (wild geranium)

Dwarf cinquefoil, plantain-leaved pussytoes, wild geranium, and jack-in-the-pulpit are blooming.

 

 

 

 

Cercis canadensis (redbud)

Trees are blooming, too. Redbud flowers are open, pawpaw buds are swelling.

 

 

Dogwood is just getting started.

 

Cornus florida (flowering dogwood)

Other species to watch for: early meadow rue, star chickweed, lyre-leaved rockcress, smooth rockcress…

 

 

 

…and always spring beauties.

Claytonia virginica (spring beauty) growing in an exposed tree root

Two Leaves

Thursday, May 18: one more trip to Rachel Carson Conservation Park to find and photograph the elusive large twayblade. Thanks to detailed directions from a friend, I found a nice group of the plants, about half of which were in bloom.

Also know as purple twayblade, brown wide-lip orchid, and mauve sleekwort, Liparis liliifolia is one of our native orchids. The two large basal leaves stand a few inches tall, while the flowering stem (a raceme) stands up to about a foot tall and produces as many as thirty flowers.

The lowest flowers open first. A colony of large twayblade will bloom for about two to three weeks.

 

All orchid flowers have three sepals and three petals, although in some species these parts are so highly modified they may not be recognizable as such. In large twayblade, the lowest petal is modified into a wide labellum (lip); the two lateral petals are very narrow and droop down inconspicuously.


You can see the two lower sepals through the labellum, which is so thin it’s actually translucent.

Large twayblade can be found in the Mid-West, Mid-Atlantic, New England, and northernmost parts of the South. It’s threatened in Massachusetts and Vermont, and endangered in Connecticut, New York, and Rhode Island. In Maryland it’s listed as S2S3/state rare.

Look for it in rich, moist woodlands. It should still be blooming in the Maryland piedmont. The purple/brown colors of the petals and pedicels make for good camouflage against the leaf litter, but the distinctive pair of basal leaves stands out.

 

“Tway” is an obsolete word meaning “two”.

Crowning Glory

Wednesday, May 10. Headed to Sugarloaf Mountain with two goals: get good pictures of pink lady’s slipper and mountain laurel. Failed both. Too late for the former, too early for the latter.

 

 

Monday, May 15. Headed to Rachel Carson Conservation Park with three goals: locate and photograph large twayblade; get good pictures of spotted wintergreen and mountain laurel. Failed to find the twayblade, too early for the spotted wintergreen, and the mountain laurels were still in bud, with only a few individual flowers open.

 

Tuesday, May 16. Headed to Carderock with one goal: photograph mountain laurel. Success! Here they were actually a little past peak bloom, but still flowering profusely.

 

There’s something about the flowers of plants in the Ericaceae (heath family) that I find especially compelling, but I can’t quite put my finger on it. Actually it isn’t just the flowers, because I find the plants themselves intriguing and lovely.

 

Mountain laurel (Kalmia latifolia) is a multi-stemmed shrub that grows to 15 feet tall, maybe taller in the right conditions, but it doesn’t grow straight. The stems twist and curve, and you can see that habit in the patterns of the bark. It has a tendency to drop all but the uppermost leaves. When in bloom it looks to me like the plant is crowned in flowers.

Like our garden azaleas and rhododendrons, mountain laurel flowers on old growth (which you can see in the first photo). New growth is pictured here (with spent oak catkins drooped on the petioles).

 

 

Identifying mountain laurel is easy, because little else has that open, gnarled habit. The leaves are evergreen. Flowers are borne in crowded corymbs, and each flower has five petals fused into a tube, with ten stamens that initially stick in little folds in the petals. The color ranges from nearly white to deep pink, with a red ring in the throat.

Like other ericaceous plants, mountain laurel loves moist but well-drained, acidic soils. When you see it, you’ll often see other plants in the same family nearby. In Rachel Carson Conservation Park, it grows on a bald knob with pinxter azaleas, blueberries and deerberries (Vaccinium species), and spotted wintergreen (Chimaphila maculata). It’s also abundant on Sugarloaf Mountain, and on a few of the ridges near Carderock. There’s a section of the Cabin John Trail that I call Erica Alley, a rocky area with plenty of ericaceous species (and other neat plants, like rock polypody, ground pine, and firmosses), including dozens and dozens of mountain laurels, too, but in all the years I’ve been hiking there, I’ve never seen them bloom. I’ve never even seen buds on them.

Mountain laurel ranges from Louisiana to Maine; it’s threatened in Florida, special concern in Maine, and exploitably vulnerable in New York. In Maryland it’s found in every county except Somerset.

 

A Vexing Violet, or, How to Overthink Identification

Ah, violets. How can something so small, delicate, and beautiful be so vexing?

Last year I wrote about Viola blanda (sweet white violet), then updated my post to say that the plant pictured might be Viola primulifolia (primrose-leaved violet). When I went back to Rachel Carson Conservation Park last week, my third goal was to find these plants and get a definitive ID.

I’m so naive.

I did find a nice stand of them, in the same place where I saw a single plant last year. With Weakley’s Flora* downloaded to iBooks on my iPhone, I perched on a rock near the trail, took out my hand lens and measuring tape, and got to work.

First step: read about the genus.

Identification notes: Viola has presented numerous problems in taxonomy, distribution, and identification…

Oh, yay. But, I knew this.

Particularly troublesome are the so- called “acaulescent blue violets”, including V. sororia, V. sagittata, V. palmata, V. septemloba, etc. They may be difficult to identify due to morphological overlap, or trying to key plants without mature leaves; in some instances hybridization may be suspect. Leaf maturity is an important feature to recognize–the earliest 1-2 leaves produced in most of these taxa are generally ovate-cordate in outline and may not display characteristic lobing, toothing, or pubescence until more mature leaves are produced, 1-2 weeks later. Specimens thus collected early in the flowering period can present the botanist with a perplexing series of plants that do not key cleanly. [emphasis mine]

Interesting, and worth keeping in mind about leaf morphology and maturity, but I was looking at white violets, not blue. So continuing…

A second troublesome group contains the small white violets, including V. blanda, V. incognita, and V. macloskeyi. These taxa have been dealt with in various ways, but resist a wholly satisfactory treatment, due to apparent hybridization…

So now what? Soldier on, use the keys. There are four of them. Four keys for a single genus.

Key C – Acaulescent Violets with stolons and white (or rarely blue) flowers

That’s the one. “Acaulescent” means “without stem”. This amuses me, because violets have stems. A major distinguishing feature among violets is that some have only basal leaves, while others have caulescent leaves (leaves on the flowering stems). I’m not sure why basal-only is termed “acaulescent”, but whatever. These plants had white flowers and no stem leaves, so Key C it was.

First couplet:

1. Flowers generally blue…
1. Flowers white…

Hey, this is easy! Second couplet:

2. Leaf blades > 1.5× as long as broad.
2. Leaf blades < 1.5× as long as broad.

Got the measuring tape, checked a few leaves… uh oh. Which leaves to measure? Each plant had several low leaves and a single larger, more upright leaf. Is that the mature leaf I should be measuring? “Leaf maturity is an important feature to recognize…” Oh, right. So I measured a few mature leaves and found that on average, they are exactly one and a half times as long as they are broad. (A few are very slightly more, and a few are very slightly less.)

The thing about nature is that it refuses to be put into neat categories. Keys are great, but they can never account for every variation. When using keys the rule is: examine multiple specimens and go with the best fit, even if it isn’t a precise fit. But I really didn’t know where to go here, so I decided to follow both leads to see what happens.

The first line of the couplet above leads to

3. Leaf blades ovate-lanceolate to ovate-triangular, 1.5-2× as long as broad, the base broadly rounded to subtruncate…  V. primulifolia 
3. Leaf blades lanceolate to linear-lanceolate, 3-15× as long as broad, base narrowly cuneate and somewhat decurrent onto petiole.

This had me scratching my head. For the most part the leaves were more ovate-triangular (first line), but the bases were more often cuneate and decurrent (second line). Since neither of these descriptions quite fit, but the first one was closer, I kept it in mind as a possibility and went back to the second line of couplet two (leaf blades less than one and a half times long as broad):

5. Leaf blades completely glabrous (petioles may be villous); [of wet, acidic seepage or swampy woods, often with Sphagnum]…   V. pallens
5. Leaf blades pubescent, at least on the upper surface of the basal lobes; [of wet to more mesic situations]

Most of the leaves were slightly to very pubescent. Also, these plants were found in a wet area, so the habitat description works, too. I chose the second line, which led to:

6. Lateral petals glabrous within; petioles and peduncles usually reddish-tinged; leaf apex acute; basal lobes of the leaf often overlapping; pubescence of the upper leaf surface often restricted to the basal lobes; [of mesic, often nutrient-rich forests]… V. blanda
6. Lateral petals bearded within; petioles and reduncles [sic] green; leaf apex obtuse to rounded; basal lobes of the leaf not overlapping; pubescence of the upper leaf surface usually widespread; [of mesic to wet situations]… V. incognita

The lateral petals were very slightly bearded, not glabrous, but the petioles and peduncles were reddish-tinged; the leaf tips were acute, but the basal lobes of the leaves were not overlapping. The pubescence was more widespread on some plants than others.

At this point I didn’t know what to think, so I turned to the internet and a few books to get descriptions of V. primulifolia and V. blanda. I’ll spare you the details, other than to say that according to Illinois Wildflowers, V. primulifolia sometimes has slightly bearded petals.

In the end it came down to looking at pictures. From all that I saw, the mature leaves of these plants look a lot more like V. primulifolia. The final check was location: are the two species found in Montgomery County? V. primulifolia is, V. blanda is not.

So with the information available and my understanding of the terminology, I’ve reached the conclusion that these are primrose-leaved violet.

Going through an exercise like this is tedious, but I do it in part to teach myself botany. How else can we learn but to question everything? I welcome discussion in the comments section, especially if you think I got something wrong.


*Weakley’s Flora can be downloaded from the University of North Carolina Herbarium website

A Mystery Shrub Identified

On April 19 I finally made it out to Rachel Carson Conservation Park for the first time this year. I had three goals, one of which was to see the stunning pinxter azaleas in bloom. I was a bit early for that.

I was almost too early for the second goal, which was to solve a mystery from the spring of 2016. One of the places where the pinxters bloom is a little hilltop of exposed rock. It must be acidic soil, because there’s a profusion of other ericaceous species: mountain laurel, blueberry, spotted wintergreen. And a spindly shrub that was in bud, but I never saw it in flower.

Until this year. Just a few buds were open on the 19th. I knew it right away for something in the rose family, and from there it was quick work to determine that it’s chokeberry (Aronia species). But I wasn’t able to determine which chokeberry until I went back on the 27th, when the pinxters were in their glory; the mystery plant was blooming, too.

This is Aronia melanocarpa, black chokeberry, a small shrub (about six feet tall) that ranges from New England and the mid-Atlantic south in the Appalachians and into parts of the Midwest. In Maryland it grows in the piedmont and areas to the west. Like the other plants I found nearby, black chokeberry prefers well-drained, moist to dry acidic soils in the woodland understory.

There are only two other chokeberry species in Maryland, A. arbutifolia (red chokeberry) and A. prunifolia (purple chokeberry). Some authorities consider the latter a hybrid of the other two species; in their texts you’ll see it written as Aronia x prunifolia. As with other members of the Rosaceae, the taxonomy of this genus is unsettled: some authors place the species in the genus Photinia, and in the past authors have placed them in Pyrus (pear) or Sorbus (mountain ash).

Whether or not you call them Aronias, the genus is easily distinguished from other similar rosaceous shrubs (like Amelanchier species). The clue is the presence of dark spots (called trichomes) found on the top surface of the leaves, along the lower part of the midrib. No other rosaceous shrubs have these. The best way to determine the species is to examine the fruit, which are colored as the common names suggest. In the absence of fruit, look at the undersides of the leaves. A. melanocarpa is glabrous (smooth), A. prunifolia is slightly pubescent (short hairy), and A. arbutifolia is densely pubescent.

As luck would have it, I have one of the latter in my yard, so here’s a look at a densely pubescent leaf.

The third goal I referred to was to make sense of a particularly vexing violet I had found the previous spring. More on that in an upcoming post.

 

So Very…

 

 

…Pink.

 

 

 

Not my favorite color.

 

 

 

 

But how can I not love this plant?

 

 

 

 

I wrote about pinxter azalea last year and don’t have anything to add.

 

 

 

 

I just wanted to post more pictures.

 

 

 

Rhododendron periclymenoides (Ericaceae) in Rachel Carson Conservation Park, April 27. Also look for them on the lower slopes of Sugarloaf Mountain.

Mid-April Update

rue anemone blooming in a patch of violet wood sorrel leaves (no flowers yet) at Rachel Carson Conservation Park

Along the Billy Goat B trail on Tuesday, there were still plenty of spring beauties, star chickweed, and field chickweed. While Virginia bluebells are waning fast, wild blue phlox is past its peak but still going strong. Plenty of Coville’s phacelia, but I wasn’t able to find any Miami mist. In a few places along footpaths between the trail and the towpath you can find wild geranium in full bloom, too. Close to the river a few stands of golden Alexanders are open.

azure bluets, violet wood sorrel, and wild pinks in dappled shade near Carderock

Small patches of violet wood sorrel are blooming along the trail and in the greater Carderock area, which is looking great, with plenty of azure bluets and wild pinks in the rocky areas. Plantain-leaved pussytoes are blooming, too, and dwarf cinquefoil is just starting. Bastard toadflax is budding up and a few days from opening. A few days behind it, perhaps, will be rattlesnake weed, also budding up. Sessile bellwort is done already, and the yellow violets are mostly done, but there’s plenty of creamy violet still. Toadshade is hanging on, but most of the other ephemerals there are done (except spring beauty, of course).

Look up: flowering dogwood and pawpaw are in full bloom.

flower buds on pinxter azalea

Over at Rachel Carson Conservation Park, the pinxter azaleas and showy orchis are in bud; the former will be open within a few days, the orchis in maybe a week. There are a few stands of azure bluets by the river, and gobs of rue anemone and spring beauty everywhere. Look for mayapples and jack-in-the-pulpit, too. There are several nice stands of perfoliate bellwort along the Fern Valley trail.

I also found a new-to-me shrub that I haven’t identified yet. Hopefully it’s something good and interesting and I can write about it in a few days.

perfoliate bellwort at RCCP