Similar to the way that people have domesticated wild varieties of cannabis, this also happened with shrooms. The Costa Rica variety from South America is a domesticated species of Psilocybe Cubensis that comes from the Arenal Volcano Hillside in Costa Rica.
This variety has been domesticated over a number of generations, but has yet to be fully stabilized. Therefore it tends to produce a number of fruits with varying sizes, all with a light tan gradient on the top of the cap.
As far as potency goes, this one variety is known to be quite potent and bruises blue readily. These are a good shroom to choose for those who have had an experience and are looking to take a step deeper.