Calvin appeared as a flower alter ego in among the Transmogrifier Gun alter egos of the first Transmogrifier Gun story arc (2/8 through 2/20 1988). Specifically, it appeared in the Sunday strip in which Calvin fought with Hobbes over the Transmogrifier Gun.
Despite being a plant, this alter ego was somehow able to operate the Transmogrifier Gun. As such, the flower supports the idea that transmogrified alter egos have unnatural capabilities: much like the safe deposit alter ego, it was able to operate the Transmogrifier Gun without any limbs.