Taken from Wikipedia:
"Mate plant, or Yerba mate (Spanish: [ˈʝeɾβa ˈmate]; (...) is a species of holly (family Aquifoliaceae), well known as the source of the mate beverage. Though the plant is called yerba in Spanish ("herb" in English), it is a tree and not an herbaceous plant. It is native to subtropical South America in northeastern Argentina, Bolivia, southern Brazil, Uruguay and Paraguay. It was first used and cultivated by the Guaraní people, and also in some Tupí communities in southern Brazil, prior to the European colonization. It was scientifically classified by the Swiss botanist Moses Bertoni, who settled in Paraguay in 1895.
The mate plant, Ilex paraguariensis, is a shrub when young and a tree when adult, growing up to 15 meters tall. The leaves are evergreen, 7–11 cm long and 3–5.5 cm wide, with a serrated margin. The flowers are small, greenish-white, with four petals. The fruit is a red drupe 4–6 mm in diameter. The leaves are often called yerba (Spanish) or erva (Portuguese), both of which mean "herb". They contain caffeine and related compounds and are harvested commercially.
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The infusion, called mate in Spanish-speaking countries or chimarrão in south Brazil, is prepared by steeping dry leaves (and twigs) of the mate plant in hot water, rather than in boiling water. Drinking mate with friends from a shared hollow gourd (also called a guampa, porongo or mate in Spanish, or cabaça or cuia in Portuguese, or zucca in Italian) with a metal straw (a bombilla in Spanish, bomba in Portuguese) is a common social practice in Uruguay, Argentina and southern Brazil among people of all ages; the beverage is most popular in Uruguay, where people are seen walking on the street carrying the "mate" and "termo" in their arms and where you can find hot water stations to refill the "termo" while on the road, Paraguay, Peru and Chile, eastern Bolivia and other states of Brazil, and has been cultivated in Syria, Lebanon and Jordan. Uruguay is the largest consumer of mate per capita.
The flavor of brewed mate is strongly vegetal, herbal, and grassy, reminiscent of some varieties of green tea. Some consider the flavor to be very agreeable, but it is generally bitter if steeped in boiling water. Flavored mate is also sold, in which the mate leaves are blended with another herb (such as peppermint) or citrus rind.
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In the Rio de la Plata region, people often consume daily servings of mate. It is common for friends to convene to matear several times a week. In cold weather, the beverage is served hot and in warm weather the hot water is often substituted with lemonade, but not in Uruguay. Children often take mate with lemonade or milk, as well.
As Europeans often meet at a coffee shop, drinking mate is the impetus for gathering with friends in Argentina, southern Brazil, Paraguay and Uruguay. Sharing mate is ritualistic and has its own set of rules. Usually, one person, the host or whoever brought the mate, prepares the drink and refills the gourd with water. In these three countries, the hot water can be contained in a vacuum flask, termo (appropriate for drinking mate in the outside) or garrafa térmica (Brazil), or in a pava (kettle), which only can be done at home.
The gourd is passed around, often in a circle, and each person finishes the gourd before giving it back to the brewer. The gourd (also called a mate) is passed in a clockwise order. Since mate can be rebrewed many times, the gourd is passed until the water runs out. When persons no longer want to take mate, they say "gracias" (thank you) to the brewer when returning the gourd to signify they do not want any more.
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