What is "marestail"

Marestail (also mare's tail and mare's-tail) can refer to:

• 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

• Grey Mare's Tail, near Moffat in Dumfriesshire, Scotland
• Grey Mare's Tail, Llanrwst in the Conwy valley in north Wales

• Mare's tail, a type of cirrus cloud formation.