Don’t Forget the Species Pages

If you ever want basic facts about our native wildflowers – like when they bloom – don’t forget to check the species pages here on this blog. Scroll to the top of this page and click on either Plant List (binomial) or Plant List (common names). From those lists you can click on links that will take you to species pages.

A note on bloom times: “early” means the first of the month to the 10th; “mid” means the 11th to the 20th; “late” means the 21st to the end. Bloom times vary, especially for plants that bloom early in the year, so if you want to see a species blooming, start looking for it at the earliest reported time, or even before.

Be cautious: “observed blooming” means exactly that. No more, no less. If I only saw it blooming in early May one year, that doesn’t mean it wasn’t blooming in mid May or late April. It could mean that I wasn’t around at other times to see if it was blooming or not.

For most of these species, the recorded bloom times were for plants found in the Potomac gorge. Plants may be blooming sooner to the south or in the coastal plain, or later to the north in the Piedmont and in the Blue Ridge.

The pages are within a few days of being up-to-date for 2017.

pictured: one of our native irises, soon to be the subject of an extensive analysis; stay tuned!

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”.

Yam, Sweet Potato, Potato… Common Name Confusion

Wild yam (Dioscorea villosa) is a vining plant that can grow to thirty feet long. The leaves are arranged in whorls, with varying numbers of leaves at each node. They’re rather handsome: large and cordate (heart-shaped), with distinctive palmate venation.


Few people notice the flowers, which are only a few millimeters wide. They’re borne in panicles in the leaf axils. The plants are dioecious, bearing either male or female flowers. Honestly, I can’t tell which these are, as the flowers are almost identical.


Is this native wildflower related to the culinary yam? Yes and no. There are several cultivated species of yam, and all are in the same genus as this plant. However, the vegetable Americans eat candied on Thanksgiving Day is not actually a yam. It’s a sweet potato, Ipomoea batata, which looks a lot like the various African yams. So common name confusion isn’t limited to wildflowers; it happens in the kitchen, too.

To add to the confusion, there’s a native wildflower that goes by the name wild potato vine, or Ipomoea pandurata. It’s also a vine with cordate leaves, but the leaves have pinnate venation. And anyway, the two flowers could hardly be more different.


As you can see from the genus name, it’s closely related to culinary sweet potatoes, but more distantly related to culinary potatoes, which are Solanum tuberosum.

I tried to make a tree to show the taxonomic relationships, but the WordPress HTML would have none of it, so here’s a chart instead.

flowering plants
monocots dicots
Dioscoreales Solanales Solanales (order)
Dioscoreaceae Solanaceae Convolvulaceae (family)
Dioscorea Solanum Ipomoea (genus)
D. villosa  S. tuberosum I. batata,  I. pandurata (species)

Hopefully it makes the point that yams and sweet potatoes are only very distantly related.

Dioscorea villosa is blooming now. Look for it twining about other plants in deep woodland shade. Ipomoea pandurata should be blooming in another month or so. Look for it twining about plants or crawling up rock faces in open, sunny areas.


partridgeberry sharing a rock with common polypody

I don’t like to play favorites. I can’t tell you my favorite food or make of car or anything like that. Often favorite is a function of context. Still, if I had to choose a favorite wildflower, partidgeberry (Mitchella repens, Rubiaceae) would be a strong contender.

So on May 16, when I went to Carderock with the one goal of photographing mountain laurel in bloom, I decided to go first to the place I call Partridgeberry Rock. Just in case. Because everything has been blooming early this year.

And so it was with partridgeberry. It was blooming at least a week earlier then I’d ever seen it bloom in past years. My mountain laurel photoshoot was on hold for at least an hour while I got out the tripod and macro lens for this tiny plant.


Partridgeberry can be described as an evergreen perennial or even an evergreen subshrub, since the stems of mature plants do lignify (turn woody) to some extent. And the plants can grow a foot or more long. (It’s a little hard to say how long an individual plant can get, since they will root at the nodes to form new plants.) However, they don’t grow taller than about two inches. They just trail along over the ground and rocks. The dark, glossy leaves measure about half an inch across.

The plants always flower in pairs, usually at the ends of them stems, but sometimes in the leaf axils as well. The dark pink buds open to reveal hairy white flowers, the four petals fusing to form a single tube with four flaring lobes. (In this particular stand several of the flowers were five-lobed.) The petals aren’t the only things that fuse: once both flowers of a pair are pollinated, their ovaries fuse to form a single fruit, which despite the common name is not a berry. It’s a drupe (stone fruit, like peach and cherry). The drupe is oval-shaped and has two dark spots on it, like little eyes.

Partridgeberry ranges from eastern Texas to Florida and Maine, and north into Minnesota (although it’s almost missing from a few of the mid-west states). It’s threatened in Iowa. The Maryland Biodiversity Project now has records for it in every county in Maryland.