The ornamental design for a collapsibleplantstand, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a collapsible plant stand which embodies the present invention and looking toward one front corner of the stand;
FIG. 2 is a perspective view of the collapsible plant stand shown in FIG. 1 and looking toward the other front corner of the stand; and,
FIG. 3 is a perspective view similar to FIG. 2 but illustrating a second embodiment of the collapsible plant stand of the present invention.
The broken lines shown in FIG. 1 of the drawings illustrate plant containers which may be used in association with the collapsible plant stand but which are shown for illustrative purposes only and form no part of the claimed design.