In the Know Horsetail is most commonly found in North America (Canada and the norther parts of United States), and got its name due to its branches that resemble a horse's tail. Formally known as Equisetum, horsetail is the only living genus in Equisetaceae, a family of vascular plants that reproduces by spores, rather than seeds. Horsetail is considered a "living fossil" because it's really, really old, perhaps more than one-hundred million years! Way back in Ancient Rome and Greece, when physicians prescribed horsetail as a diuretic, those suffering issues related to water retention found relief. Since then, Horsetail Tea has earned the reputation as an effective way to eliminate excess water in the body. In fact, Germany's equivalent to our FDA even approves horsetail as a treatment for edema. What Does Horsetail Taste Like? After dropping your unbleached tea bag into your cup of water heated to just below boiling (205° to 210° or so), let it steep 4-8 minutes.