Wildone39, All of the cats discussed are species, 'Felis concolor', or cougar. Which is just another name for what others in different regions of North america call Panther(a misnomer from early settler days of seeing the cats in the dark believing they were black panthers), Mountain lion,Painter, Catamount, Cougar, Puma, etc. The Florida panther, 'Felis concolor coryi' is a subspecies of the North american mountain lion. No mountain lions are black in color normally, and melanistic phases are very rare. There are 'red and blue' phases, rufous brown and slate gray out West though seldom seen. Most are the color of their favorite prey, deer, a tawny brown upper, and whitish lower body.
There is a species of large cat called a Pnather from SA & CA that has sometimes been reported in the Southern US, but unverifiably so. Recent work by the SW jaguar Project has found evidence of mexican jaguars crossing the US Border in AZ/NM/TX areas to date. Even these cats are not black in color, rather they are spotted look up a picture.
A young Mountain lion will have spots for up to a year;so you could have seen a younger one looking for rats, coons, or such around buildings when driving.
The FL Panther has a distinct 'crook' near the end of it's tail that looks like granma rocked on it with her rocker. Also, the FL p' is darker than any others, has longer legs and smaller feet, and is the lightest with a large male going 150lbs. genetic and regional isolation has caused dinsitinctive charcteriscs among the extremely small population as well.
They used to range from the Mid Missipi' to Fl, but man pushed them all the way down into the Everglades. they have tried to move upstate, but to no success due to the population of man in Fl.
Let me know if you have more questions...