Growing by the water. A variety of bugleweed. The genus name Lycopus means wolf foot, and the plant is so named because some varieties have leaves that resemble a wolf’s foot print. (Seems unlikely!) This species has many historical medical uses, especially as a sedative. Sessile-leaved means the leaves are attached to the main stalk without any stem. Mint Family.
Sessile-leaved Water Horehound, Clasping Water Horehound (Lycopus amplectens)