Northern bugleweed

Lycopus uniflorus, commonly known as northern bugleweed or one-flower water-horehound, is a slender herbaceous perennial in the family Lamiaceae native to wet habitats across northern North America and parts of northeastern Asia. It grows from a creeping rhizome that bears small tuberous swellings, producing erect square stems 10 to 60 centimeters tall. The opposite leaves are lance-shaped to elliptic, 3 to 8 centimeters long, sharply toothed and tapering at both ends, usually nearly hairless. Small white tubular two-lipped flowers are borne in dense whorled clusters in the axils of upper leaves from midsummer into autumn; despite the species name 'uniflorus' the flowers occur in modest clusters rather than singly. The fruit consists of four small nutlets enclosed in the persistent calyx. The species inhabits the margins of marshes, swamps, bogs, wet meadows, lakeshores and stream banks, often forming colonies through its rhizomatous spread.