St. John's-worts, for those of us in the northeast, have five petals. For a long time, that was true everywhere. Four-petaled plants were segregated into the genus Ascyron. More recently, it has been determined that they should all be treated the same. But if, like me, you look for four petals as you go south, it will be fun whatever the name. Hypericum edisonianum in particular is one to aspire to. This rare plant wasn't even discovered and described until 1933. It is only found in the highlands, if you can call them that, of the central Florida peninsula.