



Organ-pipe cactus in a desert habitot — southern Dune grass on a wind-swept seashore — Cape 

 Arizona Hatteras 



United States Department uf the liitericir; Glacier National I'ark 



Epiphytes in cypress trees in a swamp habitat — Bear gross at the summit of the Rockies — Glacier 

 Everglades, Florida Notional Park 



TYPES OF NATURAL COMMUNITIES 



If placed in one of the other environments shown, any of these distinctive plants 

 would be crowded out by the native species, or it would be destroyed by the in- 

 organic conditions 



