Monday, August 3, 2015

Prairie Grass

                                              photo by Glen Larson

Several years ago when we began planting prairie grasses on low lying, frequently wet  parts of our hay field, I recognized two different prairie grasses - Big Blue Stem with tall purplish and three flower stalks (the reason for its common name, Turkey Foot), and Side Oats Gramma, a distinctive shorter grass with all its seeds dangling from one side of the stem. I was ecstatic when I first saw the tall purplish grasses in our fields.

As that first summer progressed, I keyed out the flowers expecting to find the prairie forbs I knew we had planted - Black-eyed Susan, Purple Prairie Clover,  and Yarrow. I found the Yarrow, but all the other flowers were volunteers, not the species we had planted, and most of the blooms were thistles. This summer was completely different. Not only did we have prairie flowers, but I could identify them all, and hardly any were thistles

So, I decided to key out the grasses, hoping to find more than Big Blue Stem. My books were unhelpful. One key differentiated between reeds, sedges and grasses. Sedges had triangular stems. Grasses had round stems. That was as far as the key went. After a collecting walk, I had ten kinds of round stemmed grasses, all very different.

Photographs are really useless in a grass guide except for Big Blue Stem and Side Oats Gramma - perhaps the reason I can recognize them. Line drawings turned out to be much better for identification. I tentatively labeled one specimen Switch Grass because of the airy spray of tiny, delicate pinkish flowers at the end of each stem. Fantastic. Now I had nine unidentified samples labeled "grass."

Then I found University of California -  Davis' guide to grasses online. It was a real field guide with a real key. I got out my magnifying glass and began:
1) seed heads close to stem or standing away from stem
2) leaves clasping stem with a slit, overlapped, or continuous overlapped
3) nodes or no nodes on stem
4) shape of leaf as it meets stem
5) shape of flowers - tube-like or not
6) root structure

It was a new world. Differences I had never noticed jumped into view when I looked carefully. Switch Grass turned out to be actually Reed Canary Grass,  just as  the yellow daisy like flowers with dark centers which I had identified as Black-eyed Susans  differentiated into both Black-eyed Susans and Grey headed Cone flower when I studied them up close.

From a distance, the prairie is a beautiful sea of waving, undifferentiated flowers and grasses like something nebulous from a poem or a landscape painting. But up close,  each grass is a little miracle, flowers designed to release pollen to the winds and shoots sinking deep into the earth to ensure survival during droughts and prairie fires. Beautiful in form, function and utility.  I'll never look at grasses in the same way again.


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