Simplify the following text for a Grade 7 native English-speaking person.
Original: The genus contains about 450 species , which are found mostly in the cooler areas of the Northern Hemisphere , although there are tropical species from areas as widely separated as Madagascar and Hawaii .
Simplified: In total , there are about 450 species , which are found in the cooler parts of the Northern Hemisphere . There are a few tropical species , that grow in places like Madagascar or Hawaii .