The common cattail is not a perfect flower. The tiny male and female flowers have no petals and are separated into distinct flowering bodies. Female flowers are brown and are densely arranged around a large, thick, brown spike atop the terminal shoot. Each flower has one pistil. Male flowers are densely arranged around a smaller light yellow, pointed spike that protrudes from the top of the female flowering body. Male flowers usually have 3 stamens and generally dry up and fall off once pollination is complete.
The fruit of the common cattail is a one-seeded follicle with a unilateral opening.
The leaves are quite large with their length extending the height of the stem. They measure approximately 2.5 cm in width and are light green, robust and tapered at the ends. Common cattail leaves have no stem; the wide base of each leaf is wrapped around the stem like a sheath.
Common cattail is a marsh plant and so grows best in extremely moist environments including freshwater marshes, ditches, and shorelines.
The common cattail has large underwater/ underground rhizomes that allow for quick and dense proliferation. Dense common cattail thickets are popular nesting areas for waterfowl, and provide protected pockets in which salamanders, frogs, and fish choose to lay their eggs.
Common cattail serves as a food source and building medium for muskrats.
Red-winged blackbirds consistently use the common cattail as a perch and as a support for nests.