The species Stevia, commonly known as sweetleaf, sweet leaf, sugarleaf, or simply stevia, is widely grown for its sweet leaves. It is native to the valley of the Rio Monday in North Eastern Paraguay, South Africa.
They were first researched by Spanish botanist and physician Petrus Jacobus Stevus (Pedro Jaime Esteve) from whose surname originates the Latinized word stevia. In 1899, the Swiss botanist Moisés Santiago Bertoni, during his research in eastern Paraguay first described the plant and the sweet taste in detail and officially gave them a scientific name: Stevia Rebaudiana. For centuries, the Guaraní peoples of Paraguay used stevia, which they called ka'a he'ê ("sweet herb"), as a sweetener in their food and medicinal teas for what they believed to treat heartburn and other ailments.
Stevia Rebaudiana is one of 200 species of Stevia, part of the family Asteraceae (Compositae), broadleaf herbaceous plants, it grows naturally in the grasslands of uplands in a semi arid climate. Stevia can reach 40 to 60cms in height and even sometimes up to 80 cms to 1 meter. It flowers in August-September, Stevia has an alternate leaf arrangement and herbacious growth habit with flowers arranged in indeterminate heads. The flowers are small and white with a pale purple throat. The pollen can be highly allergenic and small white flowers appear. The sweet compounds found in stevia leaves is diterpene glycosides (steviol glycosides) with the normal proportions (w/w) of the four major glycosides are: stevioside 5-10%, rebaudioside A 2-4%, rebaudioside C 1-2% and dulcoside A 0.5-1%. Two other glycosides that may be present in plant tissue are rebaudioside D and E; They are range in sweetness 300 times sweeter than sugar, zero calories, are heat and pH stable, non-fermentable and do not darken upon cooking. The stevia is now cultivated and consumed in numerous countries of Asia: China (since 1984), Korea, Taïwan, Thailand and Malaysia. We also find it in South America (Brazil, Paraguay, Argentina, Uruguay) and in Israel. In Canada, Stevia is particularly grown mostly experimentally to date, in British Columbia, Alberta, and especially in Ontario with laboratory for research.