Thursday, October 22, 2009

Number 523

I keep lists of the plants and animals found at Blue Jay Barrens. Like most lists of this type, there was a period when species were added at a fairly rapid rate. Soon it became harder to find new additions to the list. I just added the Broad Beech Fern, Thelypteris hexagonoptera, as number 523 to my list of plants.

I was once asked how I could spend 24 years studying a property and still be finding new plants. Even though plants are pretty well anchored to the ground and can’t flee at your approach, finding them is still a matter of being in the right place at the right time. I’ve found several plants that I haven’t identified because I haven’t seen them at the time of year they display the key character I need to examine. This fern wasn’t a problem, because it showed everything I needed to see in order to make a positive ID.

This winged section of stem between the two lowest pairs of leaflets separates the Broad Beech Fern from the similar Long Beech Fern. If this is such an easy plant to identify, why haven’t I seen it before? Because, I’ve never walked at this particular spot before. These ferns are in a small cluster just a few feet across and are partially hidden by a bunch of shrubs and saplings. Assuming that a ten foot wide swath is about all I could adequately scan while walking, I would have to walk 88 miles along a rigid grid pattern to be able to say I had looked everything over once.

You should never depend on just one character when making an identification. The first thing I noticed when I found this plant was downward pointing orientation of the lowest set of leaflets. That’s an indicator of the Long Beech Fern. So why am I calling it a Broad Beech Fern?

Let’s look at some more characteristics. Subleaflets have lobed margins. That’s Broad Beech. Little hairs along the leaf margin. Long Beech again. So what do we do? Sometimes you just have to put it in your questions to ponder later pile.

Remember that individual plants within a population may exhibit some natural variation. Also remember to read the part of the description that tells you what type of growing conditions that species requires. The Long Beech Fern is to be found on wet cliff faces or steep ravines near streams. The Broad Beech Fern grows on the well drained hillsides found at Blue Jay Barrens. If I were to see a population of the Long Beech Fern, I expect I would find that the similarity between species was less than my imagination led me to believe.

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