The ginger family, Zingiberaceae, includes about 50 genera and 1,300 species of plants, a few of which have culinary or medicinal uses. The common ginger (Zingiber officinale) is one of the oldest and most commonly used spices. Ginger for these uses is obtained from the tuberous rhizome, or underground stem of the plant. The common ginger is native to Southeast Asia, where it has been cultivated for thousands of years. It is now grown commercially throughout the tropics, and was the first oriental spice to be grown in the Americas. Jamaican ginger is considered to be the finest in the world.
Zingiber officinale is a perennial, creeping plant, with reed-like, leaf-bearing stems up to 4 ft (1.3 m) high that emerge from the stout rhizome. The leaves are yellowish green, alternately arranged on the stem, lanceo-late in shape (i.e., long and tapered), and 0.5-1 in (1-2 cm) wide and up to 1 ft (30 cm) long. The cone-shaped flowers are about 3 in (7 cm) long and colored yellow and purple. They occur on stalks that grow directly from the rhizome, and are about as tall as the leafy stems.
The rhizome grows relatively quickly, sprouting new above-ground shoots as it spreads. Because the rhizomes grow roots, the ginger plant can be easily propagated by taking pieces of the rhizome and planting them in the soil. Ginger grows best in rich, sandy, partially shaded places with high humidity, warm temperature, and abundant rain. Rhizomes grown specifically for drying and grinding into a powdery spice are harvested after about nine months of growth. Ginger that is to be used fresh can be harvested as soon as about one month after planting.
Ginger is used as a flavoring in tea, wine, liqueur, soft drinks, and candies. Ginger ale, once an alcoholic beverage, is now a popular, carbonated soft drink. Ginger can be purchased fresh, dried and ground, dried whole, candied, or preserved in syrup. Medicinally, ginger has been used to relieve nausea. During the Middle Ages, ginger was used as an antidote for the plague, although it did not actually work for that purpose.