Monthly Archives: April 2017

Miterwort and Dwarf Ginseng

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The problem with writing blog posts at this time of year is that there’s so much to write about. By the time I photograph a flower and research it and publish the piece, it may very well be done for the year.

That’s probably the case with these two species, which I group together because they bloom at about the same time, and because the only place I know where to find them is about a five-minute walk from my house.

Two-leaf miterwort, also called bishop’s cap, (Mitella diphylla, Saxifragaceae) is a perennial clump-forming forb that stands about two feet tall. It’s a simple plant, with a basal rosette and one pair of leaves on the flowering stem (hence the specific epithet). The individual flowers on the raceme look like tiny snowflakes. The whole plant is so wispy that it’s easily passed by.

There are five species of Mitella native to North America, but this is the only one found in the mid-Atlantic. It’s also found in the Appalachian South, the Midwest, and New England. In Maryland it grows from the western coastal plain west to the Appalachian plateau.

A much shorter plant, also easily overlooked, Panax trifolius (Araliaceae) is somewhat misleadingly named: the leaves often have five leaflets, though two of them are quite small. Dwarf ginseng is not the ginseng of commerce: that’s Panax quinquefolius, which also has five leaflets, but the leaflets have short stalks (petiolules), which is one way to tell the plants apart.

Dwarf ginseng grows in similar habitats to miterwort, with a similar but more northern range in North America. Fun fact: according to the Illinois Wildflowers site, not only is dwarf ginseng polygamo-dioecious (with plants bearing either staminate or perfect flowers) but “individual plants are capable of changing their gender from year-to-year”.*

Plants are so cool.

*Illinois Wildflowers Panax trifolius page

Cinquefoils and False Strawberry

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The other leaves in yesterday’s photo of great yellow woodsorrel belong to another five-petalled, yellow-flowering species, Potentilla canadensis (dwarf cinquefoil). This is a low-growing vine in the Rosaceae. It favors drier, rocky soils, like wild pinks and bluets do, and can be found growing near them in the Carderock area.

This is a good example of a rosaceous flower. The five distinct petals with the sepals peeping out between them are typical of the rose family. The leaf is atypical, being palmately compound with five lobes, but somehow it still looks characteristically rose-like to me, maybe because of the toothed margins.

Dwarf cinquefoil is found in much of the eastern US, especially from South Carolina to New Hampshire and the eastern parts of Ohio, Kentucky, and Tennessee.

Much more common and widespread is a near look-alike, Potentilla simplex, common cinquefoil. Note that the flowers are almost identical, and the leaves are very similar. To distinguish between the two species, consider these characteristics:

  P. canadensis P. simplex
vines generally short, hugging the ground generally long and sprawling
leaflets toothed more or less halfway along the margins toothed most of the way along the margins
middle leaflet much wider at the end (obovate) a little wider at the end (narrowly oval)
flowers generally start at the first node on the vine generally start at the second node on the vine

Another look-alike is in the same family but a different genus… for now. Recent research suggests that Duchesnea indica, false or mock strawberry, should be considered a Potentilla*. A very common lawn and garden weed, and a weed of natural areas as well, it produces fruit that isn’t edible. Well, technically it is edible- it’s not poisonous – but the strawberry-like fruits are flavorless.

These pictures show an obvious difference between the Potentillas and Duchesnea: the former have five leaflets (hence the common name cinquefoil), while the latter have three leaflets.

*Flora of the Southern and Mid-Atlantic States, Alan S. Weakley; p. 585

Two Woodsorrels

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Reviled by gardeners, yellow woodsorrel seems to show up everywhere. I’m not sure I’ve ever purchased a gallon-size or larger plant of any sort from a nursery that didn’t have the darned thing tagging along.

I’ve never bothered to key out a sample (maybe I will soon, when it isn’t raining; it won’t be hard to find), but the little plants that some people mistake for some sort of yellow clover are likely Oxalis stricta or O. corniculata, both of which are listed as weedy or invasive by several authorities. Oxalis species have leaves that resemble clover’s, with three heart-shaped leaflets, but clover is in the Fabaceae while Oxalis is in its own family, Oxalidaceae.

But this post isn’t about the weeds. It’s about two other woodsorrels, both with lovely flowers. Both form colonies from runners along the ground, but they aren’t weedy. If I found these in my garden, I wouldn’t pull them out.

The purple flower photobombing the first picture in yesterday’s post is Oxalis violacea, violet woodsorrel. It’s a perennial forb found from the Great Plains east to the Atlantic, as far north as Vermont and south into Florida. It’s listed as endangered in Massachusetts and Rhode Island, threatened in Michigan and New York, and special concern in Connecticut. The leaves are typical for this genus except for the purple markings, which may be very faint but at this time of year are usually quite distinct. Like many oxalis species, the leaflets fold together when there is little light (including overcast days). The flowers are about half an inch wide.

The flowers of the other species, Oxalis grandis (great wood sorrel), can get even larger, up to an inch across. Note the orange-red markings in the throat (click on the picture for a larger view). There are several species with this characteristic, but none of them are found in Maryland, making this an easy plant to identify when found here. This species is somewhat more upright than other Oxalis species.

Great yellow woodsorrel has a much smaller range than violet woodsorrel: it’s found from Pennsylvania south to Alabama and west to the Mississippi River.

See the larger, deeply lobed and serrated leaves in this picture? They belong to a different yellow flower. More on that, and a closely related alien, next time.

Pinks and Blues

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Up near the Carderock climbing wall there’s a little rocky meadow area that has a delightful variety of wildflowers, usually starting about mid April with wild pinks and azure bluets.

Although the colors range from white through pale pink to bright, dark pink, wild pink (Silene caroliniana ssp. pensylvanica, Caryophyllaceae) is not named for the color, but for the shape of the petals (as if they been cut with pinking shears). Another common name for it is sticky catchfly.

This is a clump-forming semi-evergreen perennial that only grows about a foot tall at the most. It prefers dry to moist well-drained soils in rocky areas, with a bit of shade. It makes a great addition to the rock garden if these conditions are met, but in my garden the rabbits keep sampling it, so I have to use repellent. I don’t think the little beasts favor it, but when competition for food is high, wild pinks are vulnerable.

This subspecies of S. caroliniana is found mostly in the mid-Atlantic states and southern New England, with a few pockets in Ohio, Kentucky, Tennessee, and North Carolina. In Maryland look for it in the ridge and valley, Blue Ridge, and piedmont physiographic provinces, and parts of the coastal plain.

There are two other subspecies of wild pink. S. caroliniana ssp. caroliniana occurs mostly in South Carolina and surrounding areas, while subspecies wherryi is more Midwestern. S. caroliniana (subspecies not specified) is endangered in Florida, threatened in Ohio and Tennessee, and exploitably vulnerable in New York

Azure bluets (Houstonia caerulea, Rubiaceae) is one of four bluet species found in the Maryland piedmont, and can be found in most of the rest of the state, too (it’s missing from a few coastal plain areas). It’s widespread from Maine to Alabama and a few parts of the midwest.

This is a very small plant, consisting of a basal rosette of leaves and a few threadlike stems only a few inches tall, with a flower atop each. The flowers are usually light blue with a yellow throat, though they can range from almost white to moderate lavender blue. Since there can be many stems per plant and it grows en masse, it can be quite eye-catching. Other common names include little bluet, innocence, and Quaker ladies.

I have to admit, this is one of my absolute favorites. I have spent literally hours photographing azure bluets, every spring for the last few years. I can’t get enough of them.

See in the top photo the third type of flower, somewhat taller than the others? More on that next time.

Never Assume

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Every year I see this garden escapee along the Billy Goat C trail, and every year I think “yep – Muscari armeniacum“, because I know that plant from many years of gardening.

But, I’m always fact-checking (or second-guessing) myself, so I looked up M. armeniacum, just to be sure. Imagine my surprise when multiple authorities show it present in North America, but nowhere near the Mid-Atlantic.

Huh.

The same authorities show two other Muscari species, M. botryoides and M. neglectum, in the Maryland piedmont, so I checked Weakley’s Flora, and believe this to be M. neglectum. Unless it’s one of the cultivars. I think for the purposes of this blog, it’s good enough to say it’s a Muscari.

There are numerous Muscari species and cultivars in the nursery trade, all of which go by variants of the common name grape hyacinth. Previously placed in the Liliaceae, they’re now listed in the Asparagaceae. They’re easily grown bulb-forming perennials that bloom early and spread nicely in the garden, which is why they’re a problem: they naturalize a little too well.

Populations of the various Muscari are now established in much of the US, excluding the Great Plains and the mountainous and desert regions of the West. I haven’t found any official listing of it as invasive other than in Tennessee, but that may be a matter of time.

The long, grass-like leaves in these pictures belong to the grape hyacinth; it’s growing in a patch of golden ragwort, which has the heart-shaped leaves.