Most botanists know that Carex is a difficult group to master. Not because the taxa within it are necessarily obscure, but because there are just so many that it is difficult to wrap your mind around them all. Most sedge-heads get in the habit of thinking of Carex in terms of the taxonomic sections within the genus. This breaks the species into more concrete groups and allows one to digest them by shared morphological traits. That being said, it is also difficult to keep the sections straight in one's head. In order to save my brain some strain I put together the following table key to the Carex sections.In order to use it, just start with the top row and work your way down the dichotomous choices to a group of 2-4 sections. Under each section is a list of characters that should distinguish each from the other.
While the table key was devised for those Carex sections found in Missouri, it undoubtedly covers most sections in the Midwest (minus some obscure, rare or monotypic sections to the north). Also, keep in mind that this thing is hot off the presses and has not been tested or reviewed extensively so use it with caution.
If you would like to print off a copy for you home, office, clipboard or tattoo artist I have also put it on www.scribd.com where you are free to print off a copy. Click HERE to be directed to the page. You should print it on 8.5 x 14 size paper for legibility. If you print it, I only ask that you please provide me with feedback on anything from spelling to taxonomic confusion.