I claim the ornamental design for a plant identifier stake, as shown and described.
FIG. 1 is a perspective view of the plant identifier stake;
FIG. 2 is a side view of the plant identifier stake;
FIG. 3 is a front view of the plant identifier stake; and,
FIG. 4 is a back view of the plant identifier stake.
The plant identifier stake of the present invention is designed to provide means to identify a plant next to which it is place. Identification is improved by angling the identification plate on the stake.