Eupatorium perfoliatum

I’m not sure what compelled me to look closely at this particular cluster of tiny white fuzzy flowers.  They’re all over the place at this time of year, in the form of late-flowering thoroughwort and white snakeroot.  But for some reason I pulled the kayak up close to this one islet near Fletcher’s Cove, and there it was.


This was a big deal because I’ve never actually seen this plant, despite it being fairly common.  What sets it apart from the other Eupatoriums is the paired, clasping, opposite leaves that make it look like the stem is piercing a single leaf.

There’s nothing about the flowers to distinguish them from other bonesets or thoroughworts.

Boneset likes sun or a bit of shade and wet soils and is tolerant of flooding, so the rock outcrops near the banks of the Potomac are perfect habitat for it.  The native range is from Texas north into Manitoba and all the way east to the Atlantic.

The genus Eupatorium once contained hundreds or species, including (in this area) the various bonesets/thoroughworts, mistflowers, snakeroots, and joe-pye weeds.  Those last three have been moved to other genera, but that is a subject for another day.


…hey, what about the other white flowers in that picture?  Stay tuned!

Dewdrops, Part Deux

After the Franey Mountain hike, I started watching for dewdrops everywhere, every time I went out.  Here are a few I found on late-flowering thoroughwort near Carderock in the C&O Canal NHP in mid-October.



Each of these seed/filament thingies is about pinky-nail size.

I did pull out the macro lens and tripod for this shoot, but everything was drying quickly.



Flower of the Day: Late-Flowering Thoroughwort

Eupatorium serotinum; Asteraceae (aster family)


This FOTD is a little premature, as it’s still in bud, but I’m on a roll here with the Eupatoriums.  This one can grow up to five feet tall, and has longer, narrow leaves than the other species I’ve written about the past few days. The inflorescence is rather flat.


This plant, also known as late boneset, is endangered in New York.  Like most of its relatives, it can be found across the eastern US and into Canada.

Tomorrow, I’ll take a break from plants in the aster family – but not for long, because this is the time of year when they really dominate.  As of August 13, 13% of the plants I’ve catalogued this year have been in the Asteraceae.  By October that figure might be as high as 25%.  Of all the plants families on this earth, only the Orchidaceae has as many species.

Flower of the Day: Hairy Boneset

UPDATE 1/11/17: I now believe these pictures to be of Godfrey’s thoroughwort, Eupatorium godfreyanum

Eupatorium pubescens; Asteraceae (aster family)


This species is still in the genus Eupatorium (for now), and is also known as E. rotundifolium, and by the common name roundleaf thoroughwort.  Notice that the flowers are very similar in shape and size to yesterday’s FOTD.  The inflorescence is flatter, though, and in most other ways the plant looks completely different:20140731-DSC_0045The leaves are much smaller, rounder, and sessile (joy-pye leaves have long petioles at the center and lower portions of the stem).  And, the leaves are arranged in pairs on the stem instead of whorls of four.  Also, as you can see from the picture above, hairy boneset likes a drier habitat, preferring rocky upland soils.

Hairy boneset is endangered in New Hampshire and New York, and possibly extirpated in Maine.  Its native range is from Maine south to Florida and west to Louisiana and Arkansas.

By the way, the common name “boneset” supposedly derives from the plant’s use in treaing dengue fever (also known as breakbone fever).  “Thoroughwort” comes from the perfoliate characteristic of the leaves of several of these species.  (A perfoliate leaf is one in which the stem appears to pierce, or go through, the leaf.)  Later this week I’ll feature a thoroughwort.