Sedges are an acquired taste that, once acquired, deepens the pleasure of botanizing. They are grasslike plants that show their beauty not through color but through architecture. Many of them flourish in wet ground. Perhaps the most famous sedge is papyrus, which we were all taught was used by the Egyptians to make paper.
To distinguish a sedge from a grass, take a close look at the stems, which aren't round like a grass but instead are triangular in cross section. "Sedges have edges" is a fun way of describing the stems. Roll the stem between your thumb and forefinger and feel the edges. Some sedges have more rounded edges than others.
In a much larger raingarden that I manage, over in Smoyer Park, there's a massing of sedges that look like a sea of grass with little pompoms on top. I had been repeatedly forgetting the name of this one, so I was happy to see my "Seek" app (a version of iNaturalist) identify it as squarrose sedge (Carex squarrosa).
Sedges, like all plants, encourage you to look closely and make fine distinctions, which can help your thinking in other aspects of life. This one probably looks a lot like the squarrose sedge, but the seedheads are a bit heftier. My Seek app is calling it hop sedge (Carex lupulina), which I'll go with. We botany types are often in our own orbits. It really is transformative to have a fellow botanist in the form of a cellphone to carry around in your pocket.
This one has elongated seedheads in clusters. I'll call it sallow sedge (Carex lurida).
Another sedge I've been dividing and moving to new locations--in my front yard and at the Barden in Herrontown Woods--has distinctive seedheads that look like stars. Having enjoyed calling this morning star sedge, I was surprised to find Seek calling it Gray's sedge, but these are just two common names for the same plant, Carex grayi.
There are other sedges that you're likely to encounter if you gravitate like I do to wet, sunny places. Green bulrush and woolgrass are sedges that were obviously named by people who couldn't tell a sedge from a rush from a grass. Feel the edges, people.
One sedge you're less likely to encounter is tussock sedge, which I've only seen in a springfed marshy area of Mountain Lakes that is unfortunately inaccessible via existing trails.
Often contrasting beautifully with the light-green leaves of sedges is the deeper green of soft rush (Juncus effusus), which here in the Smoyer Park detention basin has achieved a lovely vase-shaped form decorated with pendulant clusters of seeds reminiscent of earrings. I've seen soft rush used as a striking specimen in gardens--not bad for a native plant that mostly hangs out in ditches and other low ground.
Sedges have edges; rushes are round, meaning that rushes have rounded stems.
Another reason I like sedges so much--along with other plants they associate with in wet, sunny places, like this Hibiscus (moscheutos)--is that so many native plant species thrive in wet ground and full sun. That, and the soft ground that facilitates weeding, makes for less work and more time to gaze across the expanse and appreciate the beauty.