Field & Street | Field & Street | Chicago Reader

Field & Street 

Sign up for our newsletters Subscribe

I have decided that this should be the year of the sedge. I have been bluffing my way through this family of plants for decades, nodding sagely when people told me that Carex jamesii or Carex laxiculmis was growing at this or that place, trying to cover the fact that I wouldn't know either one of these rare species if it turned up in my backyard. Trying to cover also the fact that without a quick consultation of the relevant books I wouldn't know whether either of these species qualified as rare or special.

I am not alone in my lack of knowledge of sedges. I would hazard a guess that more than 95 percent of my fellow Americans have never heard the word "sedge." Weed out--pardon the expression--the people who have read the name in a crossword puzzle clue list but have never knowingly seen a living sedge and you are left with a minuscule fraction of the population. An even smaller fraction can not only look at a plant and say, that is a sedge, but can tell you what sedge it is.

John and Jane Balaban are prominent among the elect in the Chicago region. Neither of them is a biologist--John teaches high school physics and math, Jane is a pharmacist--but they have spent enough hours in the field and picked up enough mosquito bites to earn the respect of the most highly trained botanists.

Every year in June John and Jane offer a one-day course in identifying sedges. Class convenes at 9 AM at Bunker Hill Woods at Devon and Caldwell. At noon the class breaks for lunch at the Balaban residence in Skokie. This is a working lunch, since John and Jane have various notable sedges growing in flower beds around their house and students are encouraged to figure out their identities. Afternoon is more sedges at Harms Woods in Glenview.

At this point you may be asking yourself, is he ever going to tell us what sedges are? Indeed I will. Sedges are members of the family Cyperaceae. Along with the family Gramineae, the grasses, they form the order Poales. They are herbaceous plants, which means they have no woody tissue. Some are annuals; most are perennials that sprout each spring from long-lived roots. Grasses are economically the most important family of plants. Without such grasses as corn, wheat, rice, oats, barley, and millet a substantial part of the human race would starve to death.

Sedges do not have that kind of direct importance to human life, though papyrus, the plant that provided the Egyptians with paper, is a sedge. But sedges are often major players in natural communities. In fact, one kind of local wetland community is called a sedge meadow. We have 13 genera of Cyperaceae in this region, but the big genus is Carex. Biologists refer to genera with many species as "speciose," and Carex is about as speciose as they come. Our local flora includes 147 species of Carex, and 136 are native. This represents 8 percent of the total number of native trees, shrubs, grasses, wildflowers, and ferns in the Chicago area.

And there you have the reason why would-be field botanists flee from sedges. One hundred and thirty-six species--almost exactly the number of breeding bird species in Cook County. You might think it difficult to learn to identify all those birds, but they are a wildly diverse group, ranging from great blue herons with six-foot wingspans to blue-winged warblers weighing eight grams. With the genus Carex, we have 136 variations on a very limited theme.

The details of the structure, shape, and location of the flowers are the essential traits used in most Carex identifications, although things like leaf width also are important for some species. Since most of the species flower in spring or early summer, by mid-July many of them are unidentifiable even by experts.

Sedges are wind pollinated, and the flowers are small and plain, with none of the bright colors or elaborate patterns usually seen in species pollinated by insects. The female flowers are small green pouches called perigynia. The seeds develop inside these pouches. The male flowers are usually just sets of scales that produce slender stamens that release pollen into the air. Within this general pattern the variations seem endless. The perigynia may grow in globular clusters or be tightly packed together in long slender spikes. They may be triangular or flattened in cross section. They may be shaped like footballs or have long, skinny necks.

Plants of the Chicago Region by Floyd Swink and Gerould Wilhelm, the absolute authority on matters botanical in our area, contains a key to the plants of the genus Carex written by Wilhelm. It runs to nine large pages of very small type, and it is filled with pitfalls.

You might reasonably ask why anybody who doesn't need to pass a test would want to get into all these technicalities. I would respond that we are human. Floyd Swink is fond of pointing out that, as a taxonomist, he is a member of the world's oldest profession. God's first commandment to Adam was that he name everything in the garden. Adam obeyed that one, and in the process gained a measure of control over all the things he named. God carefully forbade Adam from naming Him. We feel most at home not where everybody knows our name, but where we know everybody's name.

When you step off the pavement and into a natural area, the depth of your experience is directly correlated to the number of things you can name. If you operate with preschool categories like "tree" and "bird" and "bug" you are going to miss a whole lot. If you can reliably distinguish a two-spotted skipper from a European skipper or a monarch from a viceroy, if you can tell a white oak from a swamp white oak or recognize the call of a willow flycatcher, you are in a position to pick up on a lot more subtleties.

Mastering the subtleties of the sedges begins with learning to separate them from grasses. The most obvious difference is the shape of the culm--the flower-bearing stem. Grass culms are round; sedge culms are roughly triangular. "Sedges have edges" is the usual mnemonic. Roll the culm back and forth between your thumb and forefinger and you can feel the angles. Once you have got that far, your next step is to turn to a key.

Botanists use dichotomous keys all the time. As the adjective implies, these keys work by placing before you a series of either-or choices. You select your choice from the pair, and the key then directs you to the next set of choices. Choose 1A and you are directed to the pair of choices numbered 2. Choose 1B and you may be directed to the pair numbered 46. Some of the sedges in the genus Carex require six or eight choices before you arrive at an identification. Of course if you make the wrong choice at some point you become like a man lost in the woods: the farther you go the more lost you get.

To get the true flavor of Wilhelm's key to the genus Carex, you have to read the actual words. Consider this pair of choices:

"All or essentially all of the pistillate spikelets drooping on elongate, slender, flexuous peduncles.

"All but occasionally the lowermost pistillate spikelets ascending or erect on usually short peduncles."

Fortunately, there is a glossary where you can look up words like "peduncle" and "cuspidate" and "obconic" and all the rest of the specialized terms botanists use. There you can learn the differences among "scaberulous," "scabrid," "scabridulous," and "scabrous."

But note all the weaselly words, like "essentially" and "occasionally." The key is full of "usually" and "rarely" and "normally." If you have only a single specimen, how do you know if it is normal?

Actually I did fairly well during the class. I successfully keyed out plants of several species. However, since then I have spent a lot of time wandering through the key without reaching a positive identification. I have provisionally identified what I call the BPF, the Balaban Proximity Factor, as the major reason. My hypothesis is that if either John or Jane Balaban is within 20 feet of me--and therefore available for consultation--I can key out anything. If they aren't around I get nowhere.

The Balabans have made some notable discoveries in the world of sedges. One species, Carex formosa, was not known in Illinois until they discovered it along the North Branch of the Chicago River. Their discovery at Bunker Hill of a number of woodland sedges in an open meadow the Forest Preserve District had kept open by regular mowing helped shape a management plan that is returning the area to the savanna character it once had. Until recently nearly treeless, the area now supports many young swamp white and pin oaks. As we take up the task of restoring to our wildlands the biodiversity they once had, sedges will be important guides to management.

Comments

Subscribe to this thread:

Add a comment

More by Jerry Sullivan

  • Vote Kestrel!

    Neither waxwing, nor kingbird, the best candidate for official bird of Chicago is right under our noses.
    • Oct 7, 1999
  • Field & Street

    • Feb 4, 1999
  • Field & Street

    • Jan 7, 1999
  • More »

Agenda Teaser

Music
August 17
Music
Drake, Migos United Center
August 17

Tabbed Event Search

Popular Stories