Merriam-Webster Collegiate Dictionary - ephedra

 noun  Etymology: New Latin, genus name, from Latin, equisetum, from Greek, from ephedros sitting upon, from epi- + hedra seat — more at sit  Date: circa 1889  1. any of a genus (Ephedra of the family Ephedraceae) of jointed nearly leafless shrubs of dry or desert regions with the leaves reduced to scales at the nodes  2. an extract of ma huang containing ephedrine and related alkaloids and used as a dietary supplement