Photo of agave plant in East Lake Woodlands, Oldsmar, Florida (2014).
Agave (// or //) is a genus of monocots. The plants are perennial, but each rosette flowers once and then dies (see semelparity). Some species are known by the name century plant.
In the APG III system, the genus is placed in the subfamily Agavoideae of the broadly circumscribed family Asparagaceae. Some authors prefer to place it in the segregate family Agavaceae. Traditionally, it was circumscribed to be composed of about 166 species, but it is now usually understood to have about 208 species.
Chiefly Mexican, agaves are also native to the southern and western United States and central and tropical South America. They are succulents with a large rosette of thick, fleshy leaves, each ending generally 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” (“quiote” in Mexico) grows from the center of the leaf rosette and bears a large number of short, 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 cacti. They are not related to cacti, nor are they closely related to Aloe whose leaves are similar in appearance.
Agave species are used as food plants by the larvae of some Lepidoptera (butterfly and moth) species, including Batrachedra striolata, which has been recorded on A. shawii.
n the Cronquist system and others, Agave was placed in the family Liliaceae, but phylogenetic analyses of DNA sequences later showed it did not belong there. In the APG II system, Agave was placed in the family Agavaceae. When this system was superseded by the APG III system in 2009, the Agavaceae were subsumed into the expanded family Asparagaceae, and Agave was treated as one of 18 genera in the subfamily Agavoideae.
Agave had long been treated as a genus of about 166 species, but this concept of Agave is now known to be paraphyletic over the genera Manfreda, Polianthes, and Prochnyanthes. These genera are now combined with Agave as Agave sensu lato, which contains about 208 species. In some of the older classifications, Agave was divided into two subgenera, Agave and Littaea, based on the form of the inflorescence. These two subgenera are probably not monophyletic.
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, 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.