The Andean horsetail (Equisetum bogotense) is a herbaceous perennial that reproduces through spores. It has thicker less bushy whorled branches, and a silica rich rhizomatous stem, which roots grow out of, under ground. This stem is a dull dark brown color with glabrous growth aside from the sheathed segments. The plant has a history as a traditional herbal remedy, and a study of its diuretic effects on humans showed significant increases in urinary sodium, potassium, and chloride. Human and animal trials of indicate that E. bogotense has "high" efficacy as a diuretic. It is used in several modern herbal supplements.