Horsetails (Equisetaceae) are a family of flora that evolved about 375 million years ago in the Devonian Period, yet they still exist as a single genus, Equisetum. These plants are vascular and reproduce by spores, not seeds. The modern genus is small compared to its extinct relatives, which could reach up to 30 meters tall.
Horsetails have leaves that are highly reduced, and are not photosynthetic, which means that they are not able to make food in the proscess of photosynthesis. Instead, it is the stem that produces food, much like an asparagus plant. The long stem is divided into anywhere between three and 60 nodes. Bonded to the nodes are whorls (at certain nodes) that contain "branches" that stick out of the plant.