Aerial stems 1–1.5 m tall. Leaves 5–11 mm wide, longer than the aerial stems, the basal sheaths auriculate above, the mucilage glands brown, not extending onto the leaf blades. Spikes 20–45 cm long, the staminate and pistillate portions separated by 2–12 cm of sterile stem. Pistillate portions of the spikes 1–2 cm in diameter in fruit, dark brown. Pistillate flowers subtended by linear bracts with somewhat thickened, spathulate, dark brown tips, the stigmas linear to linear‑lanceolate, the stalks with white, filiform hairs slightly thickened and brown toward the tips. Fruits (including stalks and hairs) 5–8 mm long. 2n=30. May–July.

Scattered nearly throughout Missouri (U.S., Canada, south to Central America, Europe, Asia). Emergent aquatic, in marshes, sloughs, margins of ponds and lakes, wet swales of prairies, ditches, and other wetlands with standing or slow‑moving water.

There is some question as to whether this species can be considered native in Missouri. Stuckey and Salamon (1987) have suggested that T. angustifolia migrated into the midwestern United States following European settlement. Steyermark (1963) considered it native in western Missouri, especially in the alkaline seeps of Saline County, and the plants are more tolerant of saline conditions than other species of cattails. Since Steyermark’s time, however, the species has spread across the state. Its predilection for disturbed wetlands, particularly along highways, where salts accumulate from runoff following winter road salting, would suggest that it is acting as a weed. However, it is also occasionally found in higher quality marshes and other wetlands. For the present, it seems safest to consider T. angustifolia a native member of the state’s flora.

Typha angustifolia hybridizes with both of the other cattail species found in Missouri. These hybrids can be difficult to distinguish from their parental species, although they are generally intermediate between the parental taxa for most morphological characters.

The hybrid T. angustifolia ¥ T. latifolia (T. ¥glauca Godr.) is mostly sterile with abortive pistillate flowers and has spikes that remain green at maturity, rather than turning brown (although these turn brown when they dry). Although the plants tend to resemble T. latifolia in general aspect, they frequently have short sections of sterile stem between the staminate and pistillate portions of the spike and have the leaf sheaths mostly auriculate. This hybrid is known from a few widely scattered stations in Missouri, but will undoubtedly be collected more frequently in the future, as T. angustifolia continues to spread and come into contact with populations of T. latifolia.

The hybrid T. angustifolia ¥ T. domingensis is mostly fertile with the pistillate portions of the spikes brown at maturity. It generally has narrower leaves, as in T. angustifolia, but thicker spikes, as in T. domingensis. The pistillate portions of the spikes are frequently rather short (6–8 cm long). Unlike T. domingensis, the leaf sheaths are auriculate above and the narrow bracts subtending the pistillate flowers are about the same color at the tips as the stigmas. This hybrid is presently known only from Barry and Vernon Counties.