Astery Things #1: New England Aster

Symphyotrichum novae-angliae is a typical aster, with flower heads consisting of roughly 50 to 75 dark rose to deep purple ray florets ringing a button of 50 to 110 disc florets that are initially yellow but become purple with age.

upper stem leaves

There are quite a few other blue-purple flowering aster species in Maryland, but distinguishing them is a topic for an upcoming post.

flower heads forming

This species is found mostly in New England, of course, and in the upper mid-west and mid-Atlantic, but also ranges south through the Appalachians and into the Great Plains. In scattered areas of the West it’s found as a garden escapee. In Maryland, New England aster is found almost entirely from the Piedmont west, with just a few occurrences in the Coastal Plain.

pruned by rabbits!

The flowers pictured here are typical, but this particular plant is not. Usually New England aster sports one stem (or just a few) standing up to four feel tall; there may be some branching near the top. The plant shown here was pruned several times by rabbits before I got ’round to spraying repellent on it, hence the short, bushy appearance. New England aster grows in a variety of habitats, sunny to partly shady, almost always in moist to wet soils.


Clearly it makes a lovely garden plant if you can protect it from herbivory while it’s still small.



October Report

I can hardly believe it’s been more than a month since my last post. Sadly, I’ve only been out hiking three times since then. In mid-October, there isn’t a whole lot of variety to see.

Serpentine Barrens Conservation Park, October 17:

  • asters, blue and white, unknown species
  • silver rod (Solidago bicolor)
  • tickseed sunflower (Bidens polylepis)
  • hyssop-leaved thoroughwort (Eupatorium hyssopifolium)
  • goldenrod (unknown species)

Carderock, October 17:

  • white snakeroot (Ageratina altissima)
  • flax-leaved aster (Ionactis linariifolia)
  • calico aster (Symphyotrichum lateriflorum)
  • blue stem goldenrod (Solidago caesia)
  • zigzag goldenrod (Solidago flexicaulis)
  • silver rod (Solidago bicolor)

Cabin John Trail, October 14:

  • beech drops (Epifagus virginiana)
  • seedpods on downy rattlesnake plantain (Goodyera pubescens)
  • common blue wood aster (Symphyotrichum cordifolium)
  • white wood aster (Eurybia divaricata)
  • other white aster (unknown species)


common blue wood aster
Symphyotrichum cordifolium

Common blue wood aster, aka heart-leaved aster, is found all over the eastern US and Canada, with some occurences in the midwest, mostly between the Missouri and Mississippi Rivers, and also in British Columbia. The taxonomy of several species closely related to this one is in flux*, so beware if you’re using an older guidebook to try to identify asters that you find. You might not be able to say for certain which species is is, only which genus. For that matter, the older guidebooks will still give the genus as Aster rather than Symphyotrichum.




white wood aster
Eurybia divaricata

White wood aster has similar leaves to common blue aster, but obviously different flowers. This species is not as widespread, occurring mostly in the greater Appalachian region, from New Hampshire to Alabama (and possibly in Quebec and Ontario).

BONAP and the Maryland Biodiversity Project agree that common blue wood aster can be found in Montgomery and Frederick Counties in Maryland, but disagree where else in the state it grows. Both sources show white wood aster growing in more counties in Maryland. Each of these species grows one to three feet tall, common blue in moist to dry woodlands, white wood in drier areas.  The patch of common blue pictured below is along the Cabin John Trail, near the southern end. It really just lights up the whole area.


*see my post last year on the subject: Are Asters Really Asters?

Mystery Aster


As I wrote earlier this month, identifying asters can be somewhat tricky. I still haven’t tried getting on the internet and finding a dichotomous key while in the field. But one day last week, while testing a rented wide angle lens, I stumbled on these late-bloomers near Harper’s Ferry, WV. I tried to key them out using my pictures, but couldn’t quite manage – there was always one detail that was not quite right.

So I cheated and asked on an internet forum. The experts there weren’t sure, either, but the best fit to the available information seems to be that this is aromatic aster, Symphyotrichum oblongifolium. Other people keyed it out and got S. pratense (barrens silky aster), which doesn’t grow in that area, and S. novae-angliae (New England aster), which is still a possibility.

Aromatic aster grows in Frederick, Montgomery, and Prince George’s county in Maryland (per the Maryland Biodiversity Project). Otherwise in the mid-Atlantic it looks to be western, occurring in the Blue Ridge, Ridge and Valley, and Appalachian Plateau physiographic regions more than the Piedmont. It ranges west to the Rocky Mountain states, north to New York, and south to Alabama. It’s listed as rare in Indiana and is threatened in Ohio.


The asters are the latest blooming plants in this area, except for witch hazel, so it might be time to put this blog to bed for the winter soon.

By the way, the lens I rented was a Nikon 16-35mm f/4, not exactly a great choice for the close-up work that I like to do with plants, but just look at the clarity in the top photo! And at ISO 640! And that’s zoomed way in with Lightroom. Now I really want to buy this lens.


Are Asters Really Asters?


The plants we commonly think of as asters are all over the Potomac Gorge and the mid-Atlantic Piedmont at this time of year. But, botanically speaking, they aren’t actually asters. Or perhaps it would be more correct to say that they aren’t actually Asters.

20151014-_DSC0088 20151014-_DSC0089

the two photos above show adjacent leaves on the same plant

At one time the genus Aster comprised about six hundred different species in Asia, Europe, and North America, but molecular phylogeny research led to a major reclassification. As a result, only one species native to North America is left in the genus Aster. Other than that one (A. alpinus), Aster is reserved for Eurasian species. The North American aster species were placed into ten new genera.

Species in five of those genera, Doellingeria, Eurybia, Ionactis, Sericocarpus, and Symphyotrichum, are found in my geographic area of interest.


Newer guidebooks, like Clemants and Gracie’s Wildflowers in the Field and Forest, reflect these changes.

In many cases, the name change is straightforward: Aster ericoides is now known as Symphyotrichum ericoides, for example.  But in some cases – like with the flowers pictured in this post – it’s anything but straightforward.


I was studying these pictures and using the venerable Newcomb’s and Peterson’s guides to try to figure out whether they’re Aster sagittifolius, Aster lowrieanus, or Aster cordifolius (and expecting that they would likely be the Symphyotrichum equivalent). Not making much progress, I turned to the internet, and found the following:

According to USDA Plants, Aster cordifolius is now Symphyotrichum cordifolium, a name accepted by ITIS.

According to USDA Plants, Aster lowrieanus is Symphyotrichum lowrieanum, a name not accepted by ITIS, which considers S. lowrieanum to be a synonym for S. cordifolium.

And Aster sagittifolius seems not to have made the cut. Searching for it in USDA Plants leads to S. cordifolium. Searching for it in ITIS leads to both S. cordifolium and S. urophyllum.

Confused yet? So am I. And without a sample at hand I can’t really narrow them down. In order to correctly identify them, I’m going to have to either collect samples (which I won’t do, for both ethical and legal reasons), or try to use my iPhone to access a good dichotomous key on the internet while in the field. It doesn’t help that by the time I found these plants, they had lost their lowest stem leaves.  By now they might be pretty ragged.

In the meantime, I’ve decided that both common blue wood aster (Symphyotrichum cordifolium) and arrow-leaf aster (Symphyotrichum urophyllum) are pictured here. As always, I welcome correction. Including corrections of typos.  I’ve proofread this so many times I can no longer see straight.


Postscript: Just for fun, here’s an excerpt from the Astereae Lab overview of asters:
“…However, during the last decade analyses of morphology, chloroplast DNA restriction fragment length polymorphisms and ITS sequence data, and on going karyotype studies have all demonstrated that asters are polyphyletic and members of a number of very distinct phylads within the tribe…”
I researched the hell out of this subject, and used the following sources extensively:
USDA Plants database
Maryland Biodiversity Project
University of Waterloo Astereae Lab
Illinois Wildflowers

Flower of the Day: Short’s Aster

Symphyotrichum shortii; Asteraceae (aster family)


Some things to consider when trying to identify asters:

  • size of flower head
  • number of ray flowers
  • number of disk flowers
  • color of flowers (not as important as you may think)
  • shape and size of leaf, including the leaf base and leaf tip
  • leaf margin
  • arrangement of leaves on the stem and whether they’re more or less consistently sized
  • shape, size, color, and number of rows of phyllaries (bracts)
  • presence of glands
  • smoothness (or not) and color of stems

…you get the idea.  Actually this is a pretty general list, but with almost 90 species of Symphyotrichum found in the US (about two dozen in this area), you really have to pay attention to details.

All of which is to say, I’m not always sure I’ve correctly id’d all the asters I’ve been posting about.  But they sure are pretty.