Which Are the Tropical Plants?

Orchids are well-known tropical epiphytes.

Tropical plants span a range of species so numerous many may never be cataloged. Because rainforests, the typical habitats of tropical plants, are disappearing at a rapid rate, the plants not yet discovered may be extinct before they are ever recorded. But plenty of tropical plants grow in arboretums and greenhouses in every climate. Some thrive in the warmth and humidity of back yards in subtropical growing zones like those in Hawaii, parts of Southern California and South Florida.

Orchids

Tropical orchids are epiphytes that attach to trees and grow on them without becoming parasites or harming the tree. The plant's roots draw in moisture and nutrition from the air and the decaying organic matter that catches on the tree. Orchids come in all shapes and sizes but share a few characteristics. They each have three petals and three petal-like sepals; their bottom petal has a unique shape.

Bromeliads

A bromeliad everyone knows is the pineapple, and all bromeliads are related to the pineapple family. They are formed around a rosette pattern with waxy, fleshy leaves that store water and usually have a bowl at the heart of the plant to trap rainwater. The little swimming pools at the center of the plant can provide a home for tiny frogs and other small creatures. When the creatures fall into the pool and drown, or die natural deaths and slip into the water cistern in the plant, they decompose and provide nutrients for the plant.

Carnivores

Carnivorous plants don't depend on accidents to get a quick meal. Pitcher plants are tropical and toxic, with tricky, lethal adaptations that allow them to prey on rainforest insects and small creatures while remaining firmly rooted in place. The pitcher has a tempting nectar-laden lip with slippery sides that insects slide down. Once the insect is inside, the plant can snap shut, trapping the bug. But it might also let nature take its course. The pitchers have down-pointing hairs inside that make it hard to climb out. They also secrete a narcotic that disorients and exhausts the bugs. Small animals can fall in and be trapped as well. Enzymes in the plant's cup dissolve the victims so they can be absorbed by the plant. Pitcher plants are often found growing in marshes.

Lianas

Most vines, about 90 percent, grow in tropical rainforests. Lianas are some of the most fascinating. They can reach tremendous lengths, up to 3,000 feet, and begin by pushing up a woody stem from the forest floor and winding around a tree. The plant may also attach itself to a new sapling with suckers and tendrils and grow along with the tree as it reaches for the canopy high overhead. Lianas grow to the sun at the emergent layer of the rainforest and once they arrive at the top of the canopy they just keep growing horizontally, reaching other tree tops or wrapping themselves around other lianas. The heavy vines can hold trees in place during tropical storms but, if a tree hosting a liana falls, it may bring down other trees linked to the same liana chain. Philodendrons and rattan are lianas.

References

• Caltech: Learning about Rainforests
• Southeastern Louisiana University: Strata of the Rainforest
• Backyard Gardener; Plant Hardiness Zone Map