Stumbling to an Identification

by Carl Strang

Always the glutton for punishment, I had decided that this year I will attempt to identify Mayslake Forest Preserve’s sedges, grasses, rushes and the like. Carex sedges in particular represent an intimidating barricade to botanical self-assurance. The latest edition of Swink & Wilhelm lists 150 Carex varieties in the Chicago region. Recently I got the opportunity to begin this quest when I found a sedge blooming in the preserve’s south savanna.

They were growing in little tufts.

Ever the dutiful would-be botanist, I started out with the key. The first few characteristics seemed straightforward, narrowing the possibilities down to 100 species or so. But then I started running into the inevitable ambiguities. Botanical keys have a circular logic to them, from a novice’s standpoint. They often describe characteristics in relative terms, or refer to things that one may or may not be seeing. With experience, you know where to go. But with experience, you likely would not have needed the key in the first place.

So, I fell to my first backup plan. Earlier I had made a list of sedge species that, according to Swink & Wilhelm, occur in DuPage County, along with flowering dates and habitats. Focusing on the species still in the running after my first assault with the key, and tossing those whose range, phenology or habitat didn’t fit, I found I was left with 8 or so candidates. Returning to the key, I could cut out half of these. Time to cheat. I went to the Internet, plugging the remaining names into a search engine and looking at photos. Justice was served. Nothing matched. The leaves were too wide, or the clusters of flowers just looked too different.

I concluded that I must have made a mistake in one of the early pairings in the key. One of these in particular was tricky, referring as it did to pubescence or hairiness. This seems to be one of the most ambiguous categories of plant characters. Taking the other fork in the fuzziness road, I found the key leading to a couple other possibilities. One of these, when I returned to the Internet, looked like an exact match in photos on several botanical websites. Looking at the description in Swink & Wilhelm, I felt that I had found success at last: common oak sedge, Carex pensylvanica. It is a common species, matches the habitat, is one of the earliest sedges to flower in the year, is small, and the flowers extend above the tuft of narrow leaves.

There also is a terminal spike of male flowers with a sessile spike of female flowers just below, both covered with brown scales.

So, success of sorts. A purist would condemn my method, especially the reliance on photos, but I am not a botanist and so my standard has to be results. I trust that as I work more with these groups of plants I will need to cheat less and less. In any case, I feel satisfaction with this successful, if stumbling, road to identification.

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2 Comments

  1. jomegat said,

    May 4, 2011 at 8:52 am

    It’s comforting to know that a trained biologist such as yourself has the same trouble with keys that I do. My identification methods are quite similar to yours, though I tend to rely heavily on field guides.

  2. Ben Hess said,

    May 23, 2011 at 2:02 pm

    Ha, sounds very similar to my identification methods.


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