​Sparganium species

This plant grows by still or slowly flowing water, and starts its life underwater, where it is often confused with other bay grass species. It occurs in narrow bands in permanent water at the edge of lakes, rivers, streams, and ditches. It may occur in swamps or ponds which are silting up. This species can withstand prolonged immersion in water, and it is found throughout Maryland. It is recognizable because of it's stalk of large bur-like flower clusters.

The flowers appear from July to September. The flowers appear as compact heads, with the male heads being above the female heads on the same inflorescence. The spiny fruits can be found up until November. They can float for several months and have a water-repelling surface. The seeds can be dispersed by moving water and possibly also by boats and water birds.

The seeds usually germinate under water producing submerged juvenile leaves. Vegetative spread is accomplished by growth from rhizomes and detached rhizomes or uprooted plants.