I love photographing bees. Wingstem (Verbesina alternifolia) attracts them like crazy. No tutorial on bees in this post; I just wanted to share these pictures.
The five pictures below are time-stamped 10:08:29; in other words, this is how the bee moved in the course of one second. 
If you want to shoot bees, now’s a great time of year. Look for Verbesina species.
Lining the highways this time of year are lots of tall white-flowering and yellow-flowering forbs. Various species of goldenrod are among the latter, and so are two other members of the Asteraceae: wingstem and yellow crownbeard, the only species of Verbesina present in Maryland (probably).
At first glance (or at 60 miles per hour), the two look a lot alike. Each can get quite tall, up to two meters, and each has large leaves, thick-looking stems, and dense arrays of composite flowers.
But it’s easy to distinguish between them. Have a look at the similarities and differences. [In the following pairs of photos, V. alternifolia (wingstem) is on the left, and V. occidentalis (yellow crownbeard) is on the right.]
Overall form: tall plants, multi-branched, with thick stems, topped with yellow flowers.
Both have leaf-like tissue running along the stems (hence “wingstem”).
Here’s the most obvious difference: V. alternifolia leaves are mostly alternate along the stems, while the leaves of V. occidentalis are mostly in pairs along the stems.
Note my frequent use of the word “mostly”. There is a lot of morphological variation in these species. In general – and this applies to Symphyotrichum, Helianthus and many other aster family species as well – the leaves tend to get smaller as they ascend the stem, and they start to alternate at the top. You need to consider the entire plant – observe the leaf arrangement at every node, especially lower on the plant – in order to decide what the overall arrangement is.
Speaking of morphological variation, have a look at this. The flowers say wingstem, but how about those whorled leaves? I’m not sure what to think. This one plant was found in an area where both species were growing. Could it be a hybrid?
Now look at the flowers. V. alternifolia often has fewer heads per array than V. occidentalis. However, this should not be considered an identifying characteristic, especially since it’s hard to define exactly what constitutes an array. And, V. alternifolia might have a larger number of arrays (instead of the single one pictured here).
Look at the individual heads. V. alternifolia has more ray florets, generally about six; V. occidentalis has one to three. Also, it seems to me that the rays of V. alternifolia are straight and often reflexed, but the rays of V. occidentalis are somewhat twisted and stick straight out.
These two species grow in the same habitats. I find them on moist soils at the margins of the woods, the river, the canal, and roadways. If you want to get a really good look at them side by side, take a trip to the C&O Canal Lock 6 parking lot on the Clara Barton Parkway. Right between the lawn and the trees, you can find both. You can also find two other closely related astery things, but that’s the subject of my next post.
Now, about my claim that these are the only two Verbesina species present in Maryland… BONAP and USDA PLANTS both show two other species present, but neither source gives county-level data. Look at the BONAP map for V. virginica. 
It doesn’t look like this species would be present here in Maryland, does it? If it is, it’s on the lower Eastern Shore. The Maryland Biodiversity Project has no records for it, though, and classifies the other species (V. encelioides) a waif, with only four records, all in Baltimore city.
ps the top photo shows wingstem blooming above the Potomac River near Great Falls.
When an unknown plant appears in my garden, I’ll watch it grow for a season before deciding if it’s a weed.
What is a weed, anyway? My favorite definition is “a plant growing where it isn’t wanted”.
Despite this practical concept, I’ve had a hard time deciding if the Elephantopus carolinianus that appeared as a volunteer in my garden deserves weed status. It’s an interesting plant that stands about a foot and a half tall, with thick but sparse leaves that result in an open, somewhat coarse texture, and it has appealingly unusual flowers. However, it’s deep-rooted and seeds itself freely, which means high weed potential.
Unlike the other species in this series of posts, whose flower heads contain only disk florets, Carolina elephant’s-foot consists only of ray florets. You have to look very closely to see it, but each flower head contains from one to five individual flowers (usually four); each one of those flowers has a single petal that’s so deeply lobed, it appears to be five separate petals.
Look for E. carolinianus in dry soils in sunny or partly sunny areas, for example near rock outcroppings in a woodland, or in disturbed, open areas. It ranges from southern Pennsylvania (where it’s endangered) to eastern Texas. Three other species of Elephantopus are native to the US, all with smaller ranges centered on the southern states. 
Enough has been written about Danaus plexippus on the internet (including here on my blog in previous years). Here are a few pictures I really like.
sipping whilst upside-down
backlit
Next in the series of posts on composite flowers lacking ray florets is blue mistflower. Like the joe-pye weeds, blue mistflower was once placed in the genus Eupatorium, but nowadays it’s known as Conoclinium coelestinum. The flowers are somewhat similar in appearance to joe-pyes, the heads of tightly clustered disk florets with long protruding styles giving the inflorescences a fine, feathery, misty look.
click on this one to zoom in and see the minute flowers opening on the outside of the heads
Also like joe-pye weeds, blue mistflower likes wet soils; along the banks of the Potomac River, if I see joe-pyes, I’m almost certain to find blue mistflower nearby. Unlike joe-pyes, the plants are short, getting to about two feet tall in ideal conditions.
Speaking of the Potomac, I went back out to check on the spot I reported on last week, a place where in other years I would definitely find mistflower. It was all underwater again. Lots of rain upstream.
Blue mistflower ranges mostly along the Mississippi River basin and its tributaries, from southern Illinois south, and also in the eastern mid-Atlantic and the Carolinas. It’s found in most of Maryland except for the westernmost and easternmost parts of the state.
eastern tailed-blue butterfly (Cupido comyntas) sipping from mistflower
Apparently these flowers are a great nectar source for a variety of butterflies, but I haven’t seen many on it. Three years ago I wrote that I was worried that the blue mistflowers in my garden would become weedy*. “Weedy” is, of course, in the eye of the gardener. They certainly have spread, somewhat aggressively, and I’ve had to pull some out, but they haven’t reached weed status yet.
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