3-Phenylmethoxytetrahydropyran herbicides

A compound of the formula:

• ##STR5## wherein R is hydrogen, phenyl or alkyl of from one to four carbon atoms, R.sup.1 is hydrogen or alkyl of from one to four carbon atoms, R.sup.2 is hydrogen, R.sup.3 is hydrogen, alkyl of from one to four carbon atoms, phenyl or is a moiety R.sup.5 --O--CH.sub.2 CH.sub.2 --O).sub.m CH(R.sup.6)--, wherein m is zero, one or two, R.sup.4 is hydrogen, alkyl of from one to four carbon atoms, or a moiety R.sup.5 --O((CH.sub.2 CH.sub.2)--O).sub.m CH(R.sup.6)--, R.sup.5 is alkyl of from one to six carbon atoms and R.sup.6 is hydrogen or alkyl of one to four carbon atoms, with the proviso that R.sup.3 and R.sup.2 together can represent the moiety --C(R.sup.7).sub.2 --O--, wherein R.sup.7 is hydrogen or alkyl of from one to four carbon atoms, R.sup.2 representing the oxa (--O--) oxygen therein, X is halogen, and n is zero, one or two.