Compounds of Formula I and their agriculturally suitable salts are disclosed which are useful for controlling undesired vegetation ##STR1## wherein Q is ##STR2## and R.sup.1 through R.sup.7, m, n, p and q are as defined in the disclosure. Also disclosed are compositions containing the compounds of Formula I and a method for controlling undesired vegetation which involves contacting the vegetation or its environment with an effective amount of a compound of Formula I.