In that there several varieties of Ruellia, I can't give you the latin second name for your plant. It is, however , one of the two most common in Florida. It is also known as Mexican Petunia, and in this case, Dwarf Mexican Petunia. The 'standard' Ruellia (same leaf and flower can grow to 4-5 feet). Yours, as a dwarf, won't grow higher than a foot or so. These are great 'self seeders', and can get away from you in your garden.
Fortunately 'Katie Ruellia' (aka Nolan's dwarf) doesn't spread via suckers though it will seed out a bit if it's happy. HTH Chris