Cattails are wetland plants, typically 1 to 7 m tall (T. minima is smaller: 0.5-1 m), with spongy, strap-like leaves and starchy, creeping stems (rhizomes). The leaves are alternate and mostly basal to a simple, jointless stem that eventually bears the flowers. The rhizomes spread horizontally beneath the surface of muddy ground to start new upright growth, and the spread of cattails is an important part of the process of open water bodies being converted to vegetated marshland and eventually dry land.
Typha plants are monoecious, wind-pollinated, and bear unisexual flowers developing in dense, complex spikes. The male flower spike develops at the top of the vertical stem, above the female flower spike (see figure below). The male (staminate) flowers are reduced to a pair of stamens and hairs and wither once the pollen is shed, leaving a short, bare stem portion above the female inflorescence. The dense cluster of female flowers forms a cylindrical spike some 10 to as much as 40 cm long and 1 to 4 cm broad. Seeds are minute (about 0.2 mm long), and attached to a thin hair or stalk, which effects wind dispersal. Typha are often among the first wetland plants to colonize areas of newly exposed wet mud.
Some classifications include the genus Sparganium (Sparganiaceae) in Typhaceae.
The most widespread species is Typha latifolia, extending across the entire temperate Northern Hemisphere. T. angustifolia is nearly as widespread, but does not extend so far north. T. domingensis is a more southerly American species, extending from the U.S. to South America, while T. laxmannii, T. minima and T. shuttleworthii are largely restricted to Asia and parts of southern Europe.
Typha plants grow along lake margins and in marshes, often in dense colonies, and are sometimes considered a weed in managed wetlands. The plant's root systems help prevent erosion, and the plants themselves are often home to many insects, birds and amphibians.
Native American tribes also used cattail down to line moccasins and papoose boards. An Indian name for cattail meant, “fruit for papoose’s bed”. Today some people still use cattail down to stuff clothing items and pillows.
If using the cattail for pillow stuffing, it is suggested to use thick batting material, as the fluff may cause a skin reaction similar to urticaria.