Thursday, September 30, 2010
Aster Analysis With Ed
Ed Miller leads the way to the aster field at the Tanner Road Preserve near Jonesville, N.Y.
Imagine a garage-band guitarist being offered a private lesson by Eric Clapton. That's about how I felt when Ed Miller offered me a one-on-one tutorial in small white asters. Ed's a noted plant expert, and I'm a rank amateur botanizer who has struggled for years to parse out these little white flowers that all look frustratingly alike, so of course I jumped at the chance. Plus, I also got to explore another natural area preserved by Saratoga P.L.A.N. (Preserving Land And Nature), the Tanner Road Preserve, a very pretty tract of meadow, woods, and swamp in southern Saratoga County.
Our examinations were mostly confined to the open sunny areas where four species of small white asters were beautifully in bloom: Aster lanceolatus (Tall White Aster), A. ericoides (Heath or Wreath Aster), A. lateriflorus (Calico Aster), and A. pilosus (Heath or Small White Aster). There were also brilliant purple sprays of New England Aster, a species that needs no close examination to identify, since no other aster that grows around here displays that vivid a color.
But the little white ones sure do need looking at closely to tell them apart. Here, Ed uses his magnifier to peer at the bracts of a flower head. Because this flower lacked the spine-tipped bracts of A. pilosus, he determined that this one was A. lanceolatus.
In many cases, the bracts will be diagnostic. Here, for example, are the distinctive out-curving bracts of A. ericoides.
Sometimes, just a glance will be enough to tell the species apart. Here, the densely-packed floral arrangement of A. ericoides sets it distinctly apart from the surrounding A. pilosus, which has a much more open habit of bloom, as well as a larger flower.
The relative size of flower heads and the number of ray flowers can also offer clues, as this comparison of A. ericoides and A. lanceolatus reveals. Those eyelash-fine petals (actually, ray flowers) of lanceolatus are distinctive for this species. It also grows much, much taller than the other small-white-flowered ones, earning its common name of Tall White Aster.
In the case of A. lateriflorus, the angle at which the stems meet the stalk is one of the features that sets this aster apart from similar ones. Note how the stems stick out at sharp right angles. In most other aster species, that angle is more acute. Note also the preponderance of purple disks among the yellow ones. This multi-color look is what suggested the common name of Calico Aster for this species.
Now, if I can just keep all this information in my head. But sometimes it's fine to let go of the need to put a name to a flower and just stand back and marvel at its beauty. Especially when that beauty's enhanced by a visit from a Monarch butterfly.
Having resolved the matter of asters, Ed and I went for a walk through the woods that are also a wonderful feature of this nature preserve. The day was fine and the woods were lovely, and they also contained some plants I had never seen. Small-flowered Agrimony was one of them (no photo today) and Bur Oak was another. We had to hunt quite a long time to find a Bur Oak acorn, since this tree belongs to the white oak group whose sweet tannin-free nuts are much prized by squirrels. But find one we did, with its distinctive burry cap that nearly covers the nut.
I wouldn't want to step on one of these in bare feet!
We also found a few leaves that were left from last year. They look quite a bit like standard White Oak leaves with rounded lobes, except that they are distinctly top-heavy, much broader at the top than at the narrowing bottom.
While scrounging around on the forest floor looking for one of those acorns, I disturbed this tiny spider, who was hiding under the leaves. No bigger than a baby pea, it scurried away as fast as its candy-striped legs could carry it. It's only by some miracle I managed to get its picture.