Sisymbrium altissimum.
(Cruciferae) -- This member of the mustard family was imported to
the US along with many relatives; watercress, horseradish, and garlic mustard among them. The clusters
of four petalled flowers on top are one distinctive feature of this family (the name "cruciferae" means "cross"). Blooms in summer.
(Photographed in WI) |