Tom's Blog

Wednesday, September 21, 2011

Collecting rye grasses in the East Basin

Yesterday was a great day for seed collecting (until the rain started at 3 PM!). My job was to collect Virginia wild rye (Elymus virginicus), a nice rye grass that is relatively well behaved in a restoration. It is more of a savanna than a prairie grass, although it is sometimes found in prairies. It is relatively short lived, and at Pleasant Valley Conservancy it is now completely absent from several areas where it was once widespread (e.g. the Crane Prairie).

The East Basin is our newest planted prairie, and is now in its second growing season. Virginia wild rye was included in the seed mix for the more mesic parts of the site, and it has done very well. It grows as a bunch grass and this year is sending up dozens of erect flowering stems, each of which produces seeds. Because the stems are erect, it is easy to bring together 3, 4, or more flower stalks and cut the heads off all at once. I was able to fill a bucket in a relatively short time.

In addition to Virginia wild rye, the East Basin has a lot of another rye, Elymus riparius, which we did not plant. We call it woodland rye (it grows in partial shade in our savannas), although it is more commonly called riverbank rye. How did this species get in the East Basin since we did not plant it? Here is my explanation.

Before we restored it, the East Basin had become fairly wooded, although in earlier years it had been a savanna or open woodland. E. riparius had probably been common at that time, but by the time we started restoration the habitat had become quite shady, so this rye grass was suppressed. It would have been growing vegetatively but not flowering, so we would not have noticed it. But once we brought the sunlight back in, it started to flourish again, as the photo below shows.

When seed collecting, how do you tell virginicus from riparius? The seeds themselves are quite different since riparius seeds have lots of short hairs and have quite long awns, whereas virginicus seeds are hairless with short awns. However, when seed collecting you need a simpler way of distinguishing them. As the photos show, the flower heads of virginicus are fairly small and stand quite erect, whereas those of riparius are large and bend over.

Once you have the hang of it, you can move through an area and focus only on your target species. Even if two bunches are side by side, there is no chance of making a mistake. Can you tell which is which in the photo below?


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