Agave

Agave is the name of a succulent plant of a large botanical genus of the same name, belonging to the family Agavaceae.

Description
Chiefly Mexican, they occur also in the southern and western United States and in central and tropical South America. The plants have a large rosette of thick fleshy leaves generally ending in a sharp point and with a spiny margin; the stout stem is usually short, the leaves apparently springing from the root. Along with plants from the related genus Yucca, various Agave species are popular ornamental plants. Each rosette is monocarpic and grows slowly to flower only once. During flowering a tall stem or "mast" grows from the center of the leaf rosette and bears a large number of shortly tubular flowers. After development of fruit the original plant dies, but suckers are frequently produced from the base of the stem which become new plants. It is a common misconception that Agaves are a cactus. Agaves are closely related to the lily and amaryllis families, and are not related to cacti.

Agave species are used as food plants by the larvae of some Lepidoptera species including Batrachedra striolata, which has been recorded on A shawii.

Commonly grown species
The most commonly grown species include Agave americana, Agave angustifolia, Blue agave (Agave tequilana) and Agave attenuata.

Agave americana
One of the most familiar species is Agave americana, a native of tropical America. Common names include Century Plant, Maguey (in Mexico), or American Aloe (it is not, however, closely related to the genus Aloe). The name "Century Plant" refers to the long time the plant takes to flower, although the number of years before flowering occurs depends on the vigor of the individual, the richness of the soil and the climate; during these years the plant is storing in its fleshy leaves the nourishment required for the effort of flowering.

Agave americana, century plant, was introduced into Europe about the middle of the 16th century and is now widely cultivated for its handsome appearance; in the variegated forms the leaf has a white or yellow marginal or central stripe from base to apex. As the leaves unfold from the center of the rosette the impression of the marginal spines is very conspicuous on the still erect younger leaves. The tequ plants are usually grown in tubs and put out in the summer months, but in the winter require protection from frost. They mature very slowly and die after flowering, but are easily propagated by the offsets from the base of the stem.

Agave attenuata
A. attenuata is a native of central Mexico and is uncommon in its natural habitat. Unlike most species of Agave, A. attenuata has a curved flower spike from which it derives one of its numerous common names - the foxtail agave.

A. attenuata is also commonly grown as a garden plant. Unlike many agaves, A. attenuata has no teeth or terminal spines making it an ideal plant for areas adjacent to footpaths. Like all agaves, A. attenuata is a succulent and requires little water or maintenance once established.

Uses
Four major parts of the agave are edible: the flowers, the leaves, the stalks or basal rosettes, and the sap (called aguamiel—honey water).(Davidson 1999)
 * Each agave plant will produce several pounds of edible flowers during the summer.
 * The leaves may be collected in winter and spring, when the plants are rich in sap, for eating.
 * The stalks, which are ready during the summer, before the blossom, weigh several pounds each. Roasted, they are sweet, like molasses.
 * During the development of the inflorescence there is a rush of sap to the base of the young flower stalk. In the case of A. americana and other species, this is used by the Mexicans to make their national beverage, pulque.
 * The flower shoot is cut out and the sap collected and subsequently fermented. By distillation, a spirit called mezcal is prepared; one of the most well-known forms of mezcal is tequila. In 2001 the Mexican Government and European Union agreed the classification of tequila and its categories. 100% Blue Agave Tequila must be made from the Weber Blue Agave plant, to rigorous specifications and only in certain Mexican states.


 * The leaves of several species yield fiber: for instance, Agave rigida var. sisalana, Sisal hemp, Agave decipiens, False Sisal Hemp. Agave americana is the source of pita fiber and is used as a fiber plant in Mexico, the West Indies and southern Europe.


 * When dried and cut in slices, the flowering stem forms natural razor strops, and the expressed juice of the leaves will lather in water like soap.


 * The Natives of Mexico used the agave to make pens, nails and needles, as well as string to sew and make weavings. In India the plant is extensively used for hedges along railroads.


 * Agave syrup (also called agave nectar) is used as an alternative to sugar in cooking.


 * When dried out, the stalks can be used to make didgeridoos.

Ethnomedical Uses

 * Leaf tea or tincture taken orally is used to treat constipation and excess gas. It is also used as a diuretic.


 * Root tea or tincture is taken orally to treat arthritic joints.

Warnings

 * The juice from many species of agave can cause acute contact dermatitis. It will produce reddening and blistering lasting one to two weeks.  Episodes of itching may recur up to a year thereafter, even though there is no longer a visible rash.  Irritation is, in part, caused by calcium oxalate raphides.  Dried parts of the plants can be handled with bare hands with little or no effect.

Taxonomy
Agave is a genus within the family Agavaceae, which is currently placed within the order Asparagales. Agaves were once classified in Liliaceae, but most references now include them in their own family, Agavaceae. The genus Agave is divided into two subgenera: Agave and Littaea.

Agaves have long presented special difficulties for taxonomy; variations within a species may be considerable, and a number of named species are of unknown origin and may just be variants of original wild species.

Spanish and Portuguese explorers probably brought agave plants back to Europe with them, but the plants became popular in Europe during the 19th century when many types were imported by collectors. Some have been continuously propagated by offset since then, and do not consistently resemble any species known in the wild, although this may simply be due to the differences in growing conditions in Europe.

Species
There are many species of Agave, see the List of Agave species.