Friday, May 22, 2009

Identifying tiny prairie plants

This is the time of year when lots of prairie (and savanna) plants are just showing above ground. An important skill of the restoration ecologist is the identification of prairie plants at this stage, whether in a newly planted prairie or a well established site. How do you identify plants when they aren't flowering?

After a few years of experience, you'll be amazed at how easy identifying some plants at the vegetative stage is. But how do you get that experience?

The most secure way to identify a plant at this stage is to mark it with a flag and watch it periodically until it flowers. Take a few photos at the same time you mark the plant, so that you still have the image of the vegetative plant for comparison. (The early vegetative growth pattern of some species is quite different than that of the more mature plant.) Of course, this may take weeks (or months), which isn't very helpful if it's a weed and you need to pull it now.

Another way, which works fairly well for a lot of species, is to look for last year's seed heads and then follow them back to the base. The photos here and the one above show an example for great St. John's wort (Hypericum pyramidatum). Its distinctive seed heads are easy to spot in the field. Once you find the seed heads, simply follow the stem down to the ground and there is this year's growth, green and lush.













Lots of other species can also be spotted this way, such as stiff goldenrod, rosin weed, compass plant, prairie dock, pale purple coneflower, yellow coneflower, pale Indian plantain, etc. etc. The main problem with this technique is if the prairie has been burned, last year's seed heads may no longer be present, although a surprising number of species do retain their seed heads through a regular burn.



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