full size The Narrow-Leaved Cattail (Typha angustifolia) often forms large stands in marshes.

The carpellate (female) flowers form the brown clubs below the yellow spire of staminate (male) flowers.

Under the soil, their rhizomes may become intertwined and form a colony of identical individuals.

Often the carpellate seed heads are infested by the Cattail Moth whose silk helps keep the seed head intact through the winter.