
Grass identification can be tough, but I believe this is rice cutgrass (botanical name Leersia oryzoides).
This grass was growing in a wetland / streamside area in Greenfield Park in West Allis, Wisconsin, just below the artificial waterfall feature at the east end of the lagoon.
The leaves and stems of rice cutgrass are very "sticky" - they are rough or sticky to the touch and grip your hands and clothing. The leaf blades can even cut exposed skin if you brush or rub against it vigorously; I believe that is where the "cutgrass" name of the Leersia genus comes from.
Rice cutgrass is a perennial grass believed to be native to many parts of the world, including North America. It is found in wet areas and is an Obligate wetland species in the U.S. National Wetland Plant List.
It reminds me somewhat of reed canary grass (though I'm sure the differences are much more apparent to trained botanists and ecologists). Reed canary grass (Phalaris arundinacea) is an invasive in North America, whereas rice cutgrass is native. I've sometimes found them growing next to each other or intermingled, with reed canary grass generally occupying a slightly drier location. Reed canary grass also has a bit of a stick or grip to its leaves, though rice cutgrass is much stickier / rougher / sharp. Rice cutgrass also seems to grow shorter than reed canary grass, at least in southern Wisconsin.
There's a chance I have misidentified this and it is actually reed canary grass instead of rice cutgrass.
As a grass, Leersia oryzoides is in the Poales order and the Poaceae family.
Photo taken early August 2023. Original key: IMG_6424