An illustration of a flowering branch of common mare's tail; a, flower before athesis; b, flower after athesis; c, fruit. The Common Mare's tail, Hippuris vulgaris, is a common aquatic plant of Eurasia and North America. The species is also sometimes called Horsetail, a name which is better reserved to the Horsetails of genus Equisetum. These are unrelated to the water plant, though there is some resemblance in appearance.

Common Mare's Tail

An illustration of a flowering branch of common mare's tail; a, flower before athesis; b, flower after…