August Phenology

by Carl Strang

Comparison of August first flower dates and first appearances by insect species continued to show the same trends that have been consistent through the season at Mayslake Forest Preserve. The 26 plant species that I could compare among years bloomed a median of 3.5 days later than 2009 and 5.5 days later than 2010.

The first hairy aster flowers on August 24 were one day later than in 2009, 6 days later than in 2010.

As was the case in July, insect first appearances were earlier in 2010 than in 2009 (by a median 7 days), and later than in 2010 (median difference 12 days). The sample size was only 10 in each case, though.

Asters! Aargh!

by Carl Strang

Recently I tackled the identification of winter asters at Mayslake Forest Preserve. As I mentioned in the last of those two posts, I had some reservations about my conclusions. Fortunately my good friend, Indiana botanist Scott Namestnik, sent me a back-channel e-mail with some helpful comments about my admittedly shakiest ID’s. Thanks to the combination of a healing calf muscle and melting snow, I was able to get back to all the plants in question yesterday. I grabbed some chunks of plants and took them back to the office for close, bleeding-eyeballs study. (That image comes from Tom Brown, such language being one of his ways of passionately encouraging his students to push the envelope in tracking and other natural history studies). I conclude that the aster I called “hairy aster” in fact is another New England aster.

Not a hairy aster after all, this photo in fact showed a New England aster as Scott suspected. When I looked at the lower leaves I saw what I missed before, the characteristic wrap-around ears at the bases of the stalkless leaves.

The other species in question is the one I called panicled aster, the most abundant species on the preserve. I studied pieces of 8 or so different plants, and found that despite their superficial similarity there is enough variation to suggest they fall into at least two different species. Here is the photo I showed in the recent post.

This one remains puzzling.

Some of these asters are hairier than others. They also show a range of variation in the hyaline (translucent) edges of their phyllaries (flower head bracts). Though I would say that in none of them are the phyllary tips truly hyaline, as those of hairy asters should be, that may be a judgment call I am missing due to lack of experience. On the other hand, it is true that the hairier ones have more extensive hyaline edges to their phyllaries, and those edges come closer to the tips. Therefore I suspect that some may in fact be hairy asters. Others may be panicled asters. Still other species may be involved. This problem will have to wait until the next flowering season.

So, I am coming out of this experience feeling I got two-thirds of the species right, not bad for such a difficult group. More importantly, I know more than I did coming in.

Winter Asters 2

by Carl Strang

Yesterday I shared the three species of asters common at Mayslake Forest Preserve that were relatively easy to identify in their winter form. Today’s conclusion focuses on the remaining three species that are relatively common at Mayslake. These were a little trickier. First, I remembered the location of a cluster of a woodland species, the side-flowering aster.

Side-flowering aster in winter.

Side-flowering aster is a woodland species, which helps limit the possibilities as most asters grow in open habitats. I am tempted here to call in a birder’s term, “jizz,” the overall intuitive impression given by a species. This aster has a delicate sprawling appearance. Up close, you can see the feature that gives the species its name.

Side-flowering aster heads are arrayed along the top of the stem.

The heads are oriented upward along the horizontal arrays, so that they are all on one side of the supporting stem.

Side-flowering aster in bloom.

Hm. This photo doesn’t show the array very well. At least you can confirm it’s an aster. Let’s move on. The most challenging identifications were those of panicled and hairy aster. Both have linear or strap-like, stemless leaves, and array their flowers in similar ways. But would the latter’s hairiness persist into winter? After scrutinizing a lot of plants without satisfaction, I went to a place where I remembered seeing hairy asters in bloom. I was relieved to find them distinctive.

I didn’t compress this photo as much as I usually do, so you should be able to see how hairy the stems are.

The stems were hairy indeed. They also were thicker than those of most other aster species, and more of their leaves were holding on among the seed heads. Much more common were the asters I concluded were panicled asters. Like the hairy aster, at least some of their leaves hang onto the stem, mainly among the flowers.

This panicled aster was exceptional in retaining several of its lower leaves. Most have fallen off by mid-winter.

I find myself less confident with this one because I am identifying it mainly by process of elimination. It lacks the distinctive leaves of New England, Drummond’s and heath aster. It grows in open areas and is much more robust than the side-flowering aster. Finally, its stems are smooth to rough but not hairy.

Panicled aster is distinguished mainly by its middle-of-the-road appearance.

Finally, here is a panicled aster as it looks when flowering.

White flowers are common with panicled aster.

In these two posts I have shared the results of my attempts to identify winter asters. I am confident that some of the information is good, but the standard caution that should be applied to information you encounter on the Internet goes double here. If you find this topic interesting, I encourage you to try your own hand at winter plant identification.

Early Autumn Prairie Flowers

by Carl Strang

A couple days ago I updated the newly flowering woodland plants at Mayslake Forest Preserve. Today we’ll shift to the prairies and meadows. I’ll begin with a plant that in some ways is simple and plain in its structure and color, but has an eye-catching effect and is highly photogenic: yellowish gentian.

Yellowish gentian 1b

The closed flowers of the gentians are classic bumblebee blooms: it takes a powerful bug to get inside one.

Yellowish gentian 2b

Earlier I mentioned the late boneset of Mayslake’s savannas. A similar looking denizen of the prairies is the tall boneset.

Tall boneset b

Autumn is the season when the asters come into their own. Earlier I mentioned the New England aster. More recent additions are Drummond’s aster, an open-area variety of the arrow-leaved aster;

Drummond's aster b

panicled aster, which likes wetter places;

Panicled aster 1b

and hairy aster, which prefers drier soils.

Hairy aster b

Common beggar’s ticks has begun to bloom, and later I will need to be alert to avoid its grabby seeds.

Common beggar's ticks b

Partridge pea is an interesting looking herbaceous legume. I remember seeing tropical trees in its genus, Cassia, when traveling in Central America.

Partridge pea b

A final entry this time is the cinnamon willow herb, which grows in wet prairies.

Cinnamon willow herb b

There is not much more room in the season for new species to enter the scene.