"Agave 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.
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.
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.
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, though the rash is no longer visible. 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. If the skin is pierced deeply enough by the needle-like ends of the leaf from a vigorously growing plant, this can also cause blood vessels in the surrounding area to erupt and an area some 2.36 - 2.75 inches across appear to be bruised. This may last up to three weeks."
Taken from wikipedia's page at: http://en.wikipedia.org/wiki/A...