Bob Walter, age 13, of Bethel Park, Penna., for his question:
What is an epiphyte?
When conditions are right, the average plant gets along very well by itself. It sets down roots which soak up minerals and water from the soil. It spreads forth leaves which make plant food from air, water ,and sunshine. By and large, a plant is a very independent unit of life ‑. or so it seems. Actually, the soil it needs was made rich. with chemicals from decaying leaves and from former generations of plant and animal life. Our independent plant must also grow where there is plenty of air and sunlight.
The average seed cannot grow where these bountiful conditions do not exist. Because a seed is helpless to move to better conditions the parent plant produces countless seeds, hoping that a few lucky ones will succeed. Sometime in the dim, distant past there were some unlucky seeds who refused to give up. They decided to take what they could get, even if it meant taking advantage of another living plant. These tenaceous seeds became the ancestors of our parasites and epiphytes, plants which take advantage of more successful plants.
The true parasite sends down suckers into the veins of a host plant. It may live entirely or only partially on food inside the host plant. The mistletoe is one of the partial parasites. It saps up moisture and minerals from the host plant, but it also has green leaves and makes its own food. Some of this food is returned to the host plant.
The epiphyte plants are not too greedy. They are all small, rather fragile plants unable to sprout up high into the sunny air. They need a bigger plant merely to stand on its shoulders where they can breathe freely and soak up the sunshine. For this reason„ the epiphytes only grow holdfasts to anchor themselves to a tall sturdy plant.
Spanish moss is an epiphyte. It usually anchors high in the branches of a big tree. Its foliage is a mass of green grey leaves which soak up moisture from the damp air and manufacture food from air, water and sunlight.
The bromelia is an epiphyte which often enjoys life high in the branches of a live oak in southern Florida. It is a graceful tuft of sword‑shaped loaves and it adds a touch of bright green foliage to the gnarled old tree. Many orchids are epiphytes. They grow in tufty bunches high in the branches of tall tropical trees. Under the green leaves there are masses of roots, always ready to soak up moisture. The tree merely provides these orchid epiphytes with a shoulder on which to perch.
The most amazing epiphyte is a vine called dischidia, a native of the tropical forests of the Old World. This vine has pitcher‑shaped leaves which trap blowing dust and moisture. The leaves become little flower pots filled with home made soil. Little roots grow into these pockets of soil and apart from borrowing a perch from a taller tree, the dischidia is quite self supporting.