The Master Gardener
Nemesis: Martian Manhunter
Other Major Foes: None
Appearances: 1 comic story
Powers: Super strength, speed, invulnerability, flight, telepathy, intangibility, invisibility, and shape-shifting
The Master Gardener used his knowledge of organisms to survive the plague which wiped out most life on Mars, and then to enslave the Lizard Men as surrogates for his lost people. Next, the Gardener conquered mid-20th Century Earth by contaminating human life with a fungus that caused spontaneous combustion in the unruly. The conspiracy was uncovered by the Manhunter from Mars, and the Gardener was unintentionally killed by his own men.
Win: Cabal (4/1)
Lose: Ma'alefa'ak (5-13); Gorilla Grodd (3-7)
The Floronic Man
Nemesis: The Atom
Other Major Foes: Swamp Thing, Batman
Appearances: 100+ comics, as well as a cartoon, video game, and the film Batman and Robin.
Powers: Control of plant life.
Jason Woodrue at first appeared to be a typical Silver Age mad scientist, but was in fact a he-fairy exiled to Earth from some sort of Ferngully dimension for being too bad for the Tinkerbells. The plainclothes Plant Master fought the Atom a couple of times before turning himself into a leafy mutant in an issue of The Flash. This led the Floronic Man to a Bronze Age revival as a member of the Secret Society of Super-Villains who frequently faced the Justice League of America. When Alan Moore first took over Swamp Thing, he used Woodrue as a foil for his initial story arc, and the fiend made reappearances across the life of the series. Woodrue was regrettably grounded in the mainstream DC Universe when the Guardians of the Universe and the Zamorans chose him as one of the New Guardians from Earth who were supposedly destined to guide the next millennium. Instead, "Floro" was somehow among the least ridiculous members of a hilariously misguided X-Men riff that involved such atrocities as an AIDS vampire, a super-menace powered by cocaine, and the resolution of African apartheid through punching. Being insane, it was simple enough for him to revert back to villainy, and somehow manage to get himself retroactively inserted into Poison Ivy's origin.