Such a fun one, and trade cards for vegetable seeds are my favorite. Especially a giant beet on wheels pulled (punningly) by a beetle! (Clever.) I can't find another like it out there, though have found a few references to Clapp and Treat seeds; I believe this dates to the 1890s or so.
5" x 3", good condition, bright and crisp, with a bit of stain visible along left edge and some old glue staining (not sticky) around the edges of the reverse side.