The ornamental design for a planter, as shown and described.
FIG. 1 is a front elevational view of a planter showing my new design, the
side and rear views (not shown) being identical thereto;
FIG. 2 is a top plan view;
FIG. 3 is a bottom plan view; and,
FIG. 4 is a perspective view.
The broken lines of FIG. 4 showing an arrangement of flowers and plants,
and soil, are for illustrative purposes only and form no part of the
claimed design.