I think the plural is agaves.

Agave plants are commonly called "century plants". Agaves can be grown in a commercial cactus mix, species of agaves.

helios.bto.ed.ac.uk/bto/desertecology/agaves.htm + Eurodicautom

--------------------------------------------------
Note added at 2002-09-11 18:57:40 (GMT)
--------------------------------------------------

The genus Agave occurs natively in arid and tropical regions from the southern USA to northern South America, and throughout the Caribbean. More than 200 species are recognized.
The name agave is derived from the Greek and means \"noble,\" referring to their tall flower stalk. Some agave species have stalks reaching 40 feet. Agaves have many common and native local names including maguey, mescal, lechuguilla, amole and Century Plant.

Agaves are rosette plants that live for several to many years before flowering. Each rosette will flower only once, then die. The English common name, Century Plant, is based on the mistaken belief that the plants grow for 100 years before blooming. In fact, some of the smaller species flower when only 3 to 4 years old. The larger species may live for 40 to 50 years before flowering

http://www.dbg.org/Collections/agave.html

HTH