Wild Beet, Beet
Introduced biennial forb to 75cm tall or sprawling. Leaves forming a rosette at the base, flat, blades to 5cm long, hairless, margins entire. Flowers small (less than 3mm across), in clusters of 3 or 4 subtended by leaf-like bracts, forming an interrupted spike.
eFloraSA description with line drawings: http://www.flora.sa.gov.au/cgi-bin/speciesfacts_display.cgi?form=speciesfacts&name=Beta_vulgaris