Stevia leaf (Stevia rebaudiana) is a soft, bushy South American herb whose small green leaves taste astonishingly sweet — many times sweeter than sugar — yet carry almost no calories. Chewed fresh or dried and steeped, the whole leaf lends its sweetness and a grassy, faintly licorice-and-menthol herbal note to teas, maté, fruit drinks and desserts. It is the plant the refined sweeteners are made from, but the leaf itself is a distinct culinary herb, greener and more herbaceous than the purified white powder.