Tropical rainforests provide an environment with warm temperatures and high moisture levels supporting some of the most dense plant populations on earth. Whereas a temperate forest may have only a handful of different tree species per acre, a tropical rainforest averages about 80 species. Additionally, there are a great many unique plant species that can be found nowhere else on earth but in the rainforest. Even some of the most beloved houseplants, like orchids and bromeliads, originated in the rainforest.
Orchids are highly differentiated among the 20,000 or more varieties believed to live in the rainforest. Tree orchids are non-parasitic plants with long vinelike roots that wrap around tree branches and trunks, collecting nutrients from rain water. Ground orchids have more traditional root structures but may grow much larger than their tree-dwelling counterparts. All orchids share the three-petal, three-sepal flower structure.
Bromeliads, like the pineapple, grow in the crooks of tree trunks in the rainforest. Their shape allows them to easily collect rainwater in deep channels along their thick, waxy leaves. The cups of captured water provide sustenance for the plant and a home for amphibians and insects, like frogs and mosquitoes.
Banana plants, commonly mistaken as trees, are actually very tall herbs. They are indigenous to South Asia and northern Australia but are now cultivated in every humid tropical rainforest climate on earth, and are the most popular fruit in America. Cacao trees thrive in warm, moist climates that receive at least 4 inches of rain per month. These shade-tolerant trees can be found throughout Central and South America. Coffee plants were originally found in equatorial Africa, but today Latin America grows more than two-thirds of the world's coffee.
Nepenthes, more commonly called "pitcher plants" are found in tropical rainforests throughout the world. Their leaves form themselves into special pitcher shapes with a sticky, digestive liquid in the bottom of the pitcher. The plant draws insects and even small animals to the pitcher by producing a sweet nectar along the rim. Animals that fall in are trapped in the sticky liquid, drown, and are digested by the plant.