Family: Agave (Agavaceae)
Size: To 2 in. long on a stalk up to 30 ft. long.
Other names: Palmilla, soaptree, Whipple yucca, Spanish bayonet
Notes: 9 species of Yucca in Arizona.
Soaptree Yucca plant profile on the USDA Plants server.
This plant is found on the Appleton-Whittell Research Ranch Working Check list of flora.