Agavaceae is the botanical name of a monocot family of flowering plants in the order Asparagales, more recently reduced to the subfamily Agavoideae of the family Asparagaceae. The group includes many well-known desert and dry zone types such as the agave, yucca, and Joshua tree. There are about 550-600 species in around 24 genera, widespread in the tropical, subtropical and warm temperate regions of the world.
The Cronquist system for classifying flowering plants treats the group as the family Agavaceae. The Angiosperm Phylogeny Group's 2009 classification (the APG III system) places the Agavaceae, along with a number of other families, in an expanded family Asparagaceae, where it may be treated as the subfamily Agavoideae.
Description and use
Species may be succulent or not. In general, Agavaceae leaves occur as rosettes at the end of a woody stem, which may range from extremely short to tree-like heights, as in the Joshua tree. The leaves are parallel-veined, and usually appear long and pointed, often with a hardened spine on the end, and sometimes with additional spines along the margins.
Agave species are used to make pulque and mezcal, while others are valued for their fibers. They are quite popular for xeriscaping, many types having showy flowers.
The circumscription of this family has varied widely. Some genera (e.g. Cordyline and Dracaena) are sometimes separated off into a separate family, Dracaenaceae, though recent research has tended to incorporate these into a larger family Ruscaceae. Nolina, Beaucarnea, and Dasylirion are sometimes recognized as Nolinaceae or placed in Ruscaceae. Conversely, data from molecular systematics now suggest that Agavaceae should be broadened to include a number of genera previously classified elsewhere, among them Chlorogalum, Camassia and the family Anthericaceae with anything up to 22 additional genera. The Angiosperm Phylogeny Group's 2009 classification classification places Agavaceae, along with a number of other families (including Ruscaceae) in an expanded family Asparagaceae, rejecting the alternative of keeping some of the families separate, as was permitted in their earlier 2003 proposal. Members of the APG have proposed the subfamily Agavoidae as a replacement for the old Agavaceae. Many sources have retained Agavaceae (in varying circumscriptions) as a family distinct from Asparagaceae. Hesperocallis, sometimes placed in its own family, Hesperocallideaceae, has recently been shown to be closely related and its inclusion in Agavaceae has been recommended.
Full article ▸