Tropical regions, because of the very moist air, the frequent showers of rain, and the absence of frost, support very prolific vegetation. The tropical rain forest is the most complex environmental system on earth, with plant and animal life richer and far more diverse than any other type of forest. For example, a five-acre sample of rain forest may have 100 different trees, compared with 25 different species in the richest temperate North America forest. Varieties of birds may be compared on a similar scale, with a rain forest in Panama having perhaps 600 different bird species, while a similar area in the temperate forests of eastern United States may have only 100. And the number of bird species is very small compared with the number of insects.
Vegetation in the tropical rain forest is arranged in stories, or strata, often called A, B, C, D and E, A being the treetops and E being the ground level. Levels A and B together form what is called the forest canopy. Here, in this canopy, where exposure to sunlight is high and the temperature rises most during sunny weather, are found a proliferation of plants commonly called “air plants,” or perching plants; more precisely, epiphytes.
Epiphytes are not a species or a family. They are a type of plant, singled out by how they obtain their food and moisture—in a very specialized way designed by our Creator.
The name is derived from two Greek words, epi meaning “upon,” and phyton meaning “plant.” Epiphytes perch on the branches or limbs of other trees, like birds on a roost, entirely independent of their host except for support.
They are not parasites. They do not, in most cases, harm their host, except by their sheer weight on the branches, or by usurping air and light from their host.
Now we want to observe how singularly this type of plant has been designed by our great Creator to survive in its unusual situation. For there are not just one or two epiphytes in the world—botanists have estimated that there may be 30,000 different epiphytes in a single rain forest. They are the clusters of ferns, the dangling cacti, the carpets of low growing shrubs and small trees, the clinging mosses and algae. The high humidity of their environment makes for their luxuriant growth.
What are the most common epiphytes?
Vanilla Orchid – National Park Service
Orchids far outnumber any other plant in having epiphyte varieties. The exact number of orchid species is not known, but someone has estimated that there are at least 20,000 species growing in the canopies of a forest in Central America alone. In their elevated homes, they assume a fantastic diversity of growth forms, from sprawling vines and dangling, rope-like strands to bushy clumps with massive leaves and compact, mossy growths that carpet the upper tree limbs. A single tree in a Venezuelan rain forest disclosed 47 different species of resident orchids.
Another plant commonly growing as an epiphyte is the bromeliad (pronounced bro-me’-li-ad). Found almost exclusively in the tropics, bromeliads are mostly short-stemmed plants with stiff thick leaves rising in a rosette. The best known bromeliad is the pineapple, but the pineapple is not an epiphyte as it grows rooted in soil.
Bromeliads & Orchids
A widely known epiphyte is the vanilla orchid of Florida, which produces seed pods that are the source of natural vanilla flavoring. These vanilla orchids are grown commercially on various tropical islands. But in these areas, they must be hand pollinated because the insects normally pollinating this type of orchid are not present.
The strangler fig starts out as an epiphyte, sprouting from a seed deposited by birds high on tree limbs. The germinating seed sends a small sprig of leaves upward and thread-like aerial roots down toward the ground, where they burrow into the soil. In a short time, these roots enclose the host trunk in a network of stout, woody roots that may kill it, leaving the strangler as an independent tree.
Trees in our temperate zone have as epiphytes only small plants such as lichens, fungi, a few ferns, and Spanish moss. In the rain forests of the tropics, where the rainfall may be as much as 12 to 14 feet per year, and fogs and mists are common, perching plants are so numerous that the tree underneath is hardly recognizable. Because Europe has no tropical areas, early explorers to North America were not familiar with epiphytes. Columbus, arriving in the Caribbean area, commented in his diary about the unusual looking trees that “had several kinds of leaves”—perching plants.
Strangler fig courtesy of L. Shyamal.
How Do Epiphytes Get Water?
Epiphytes, because they have no roots, have been designed with other—unique—means of obtaining water. A few species send long aerial roots toward a nearby stream, then pipe the water back—sometimes as far as 60 feet (what law of evolution taught them to do this?).
Other epiphytes grow roots into the air, through which they absorb moisture directly from the humid atmosphere. Many orchids put out finger-like aerial roots tipped with “sponges” that collect water from the air. If more water is collected than the plant needs, the plant stores the excess in special water bulbs inside the plant. When water is in short supply, the plant draws from these reserves (did the plant devise this singular technique by itself?).
Some epiphytes, like desert plants, have waxy coatings on their leaves and stems to cut down on water loss (what feat of “chance” gave them this protection?) Others are equipped with very thick leaves to store water.
Some epiphyte ferns, clinging to the trunk of a tree, are able to catch and hold their water supply in cup- or pitcher-like bases. Bromeliads, perched high on tree limbs in the tropics, are veritable cisterns, their large bracket leaves overlapping to hold water. These cisterns, varying in size from a few inches in diameter to as much as several feet across.
Bromeliads are distinctly adapted to the climates in which they grow. A variety that grows in full sun, for instance, is equipped with a thick tough leaf with well protected openings to insure minimum moisture loss. The types that grow deep in the forest have a small requirement for light but very large requirements for water and temperature.
Varieties that grow high in the bare Andean Mountains require a maximum amount of light and have a tolerance for extreme summer-to-winter temperature cycles every 24 hours. The flowers of these plants have coverings over them like a dense mat of wool formed by finely divided scales, to protect the flower from the extreme weather changes. (Can we think that the plants developed these singular features by chance?)
How Do Epiphytes Get Nutrients?
Here again is evidence of our Creator’s handiwork. The same leaves that catch water also catch and hold debris, which decomposes to form humus that feeds the plant.
Certain epiphytes of the bromeliad family show outstanding evidence of design. These plants have large pores on their leaves through which the plant can absorb nutrients from the water it catches in its cup-shaped cisterns. These cisterns also contain a variety of animal life (frogs and their tadpoles, dragon flies, nymphs, katydids, insect larvae, mosquitos, and even crabs). When these animals die, they become fertilizer (food) for the plant.
Orchid seeds, tiny travelers
As remarkable as orchid flowers are, their dust-like seeds—so tiny that a single pod may contain millions—are one of the wonders of our Creator’s design.
Needing to travel hundreds of miles easily on the wings of the wind (so they can alight and begin life in a treetop), they are the lightest weight seed known. This is possible because they do not need a store of food—which is the largest part of other seeds.
The seeds germinate with the aid of special fungi, which also provide essential nutrients. Is it not another wonder of our Creator’s design?
How Are Orchids Pollinated?
That depends on the type of plant. Most orchids have a convenient “landing strip,” beautified with patterns of color to attract insects to the exact part of the flower where the work of pollination must be done. Since specific varieties of orchids depend on very specific insects to pollinate them, many orchids manufacture just the right fragrance to attract the right insect. (Did a certain orchid “try out” one fragrance after another to find the “right” one that would entice the needed insect?) Some offer sweet perfumes; still others, wanting to attract flies, smell like rotting meat.
Some orchids even time the release of their fragrance to the time of day that the right insects are out. (Did this come about by evolution?). Orchids to be pollinated by insects that fly by day release their perfume during daylight. Orchids that are pollinated only by night-flying moths release their perfume only at night. Other orchids vary their fragrance, offering lily of the valley perfume by night and a rose scent by day. According to a certain evolutionist, orchids have “a timed release factor that has developed over eons of time. ” (We wonder how the orchid survived during these eons until the “timed release factor” was perfected!)
Is it not a marvel of our Creator’s handiwork? What can we say, but that “The hand that made them is Divine”!
Scientific Data in this Article is From: