Cow fields in cow patties for the standard psychedelic mushrooms (Psilocybe Cubensis). Though MANY law enforcement are aware of mushroom hunters and actively patrol the side roads of fields looking for them (some even have night vision equipment, your tax dollars at work). An if your on someone else's property you pick up a Tresspassing charge whether you have anything on you or not. You must also prove that you did not know that the mushrooms you picked contained the schedule 1 substance Psilocybin and if you have any pass drug charges it will be pretty hard to convince a judge. Not trying to shy people away from it just know the risks involved. As Ndangered said there are loads of exotic mushrooms in FL which do not require illegal tresspassing to access, it's just proper identification of them is usually harder than with Cubensis.
