Marestail (also mare's tail and mare's-tail) may refer to:
Plants
edit- Conyza canadensis, an annual weed also known as horseweed and Canadian fleabane
- Equisetum, a fern ally also known as horsetail and pipeweed
- Hippuris, a genus of aquatic flowering plants, including:
- Hippuris vulgaris, the common mare's-tail
Other
edit- Mare's tail, a type of cirrus cloud formation