Century Plant, American Aloe
Introduced plant to 12m tall when flowering. Leaves fleshy, in a basal rosette, 100-200cm long, 150-250mm wide, flat, hairless, margins with spiny teeth, with a sharp pointed spine at the tip. Flowers tubular, yellow or greenish yellow, with 6 lobes, in a many flowered panicle at the top of the flowering stem, which arises from the base of the plant. Each branch of the panicle umbel-like. Family Agavaceae in NSW and SA.
Description and photo (as Agave sp.) in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales page 190
Weeds of Australia Biosecurity Queensland Edition description: http://keyserver.lucidcentral.org/weeds/data/03030800-0b07-490a-8d04-0605030c0f01/media/Html/Agave_americana.htm