Friday, October 21, 2011

Lavender Aster

Fall is a time of asters. Most are tolerant of a few frosts, so it’s not uncommon for them to dominate the October fields. Some species are so easy to identify that they shout their names from across the field. Others maddingly share common characteristics that sometimes make them almost impossible to sort.

Blue Jay Barrens has a lavender colored aster that thrives in the dry prairie openings. I visited this particular plant several times when I first began teaching myself plant identification. Each visit left me frustrated. It seemed that I could run the plant through the keys six different times and come up with 6 different answers. This cluster of species all showed a wide variation in characters and those variations broadly overlapped across multiple species. I got so I would hurry past these plants just so I wasn’t tempted to waste more time on fruitless identification efforts.

Two things happened to improve the situation. One – I began to learn plant identification techniques and terminology. Two – Improved identification texts became available. My frustration level decreased as I was able to identify more plant species. That doesn’t mean I’m not still baffled by some descriptions of plant parts. The green shape shown here at the tip of the phyllary is one that I’m still not comfortable with. In some species it’s referred to as a diamond shape and in other species it’s referred to as rhombic in shape. If you check the definition of rhombic, you find that it means diamond shaped. So how does this help in sorting out the species?

One thing I learned early on was the fact that you seldom identify a plant on the basis of a single characteristic. Someone took the time to create a short paragraph describing the various features of a particular species, so it pays to check all of the features, including habitat requirements, before coming to a final conclusion. When I saw this aster for the first time, I remember thinking that these leaves alone should be all I needed to tack a name to the plant. A thick, rough leaf with a winged petiole couldn’t be a common occurrence. What I didn’t pay attention to was the fact that the leaves growing from the lower part of the stem were heart shaped and did not have a winged petiole. Now, that’s something I should have paid attention to.

Then there’s the stem itself. I was so fixated on what I thought had to be the key characteristic that I overlooked other vital clues. Plant identification is like solving a mystery. You have to keep adding pieces to the puzzle until the picture becomes clear. In this case the hairy stem helped to separate this aster from others with winged petioles.

Finally we have a third type of leaf growing from the upper portion of the stem. The clues eventually lead to Aster undulatus, an aster that typically grows in dry soil of open woods and clearings. One last source of aggravation is the frequency with which plant names seem to change. The genus name Aster is no longer used for this plant that took me so long to identify. I guess you have the choice of learning the new names, or doing what I’ve done and stop buying any more new botany texts.

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