DISCOVERING EVERGLADES PLANTS AND ANIMALS (continued)
Air Plants
Long before you have learned to distinguish the major
plant communities, you will be aware of the air plantsor
epiphytesthat grow so profusely in Everglades. Epiphytes are
non-parasitic plants that grow on other plants, getting their
nourishment from the air. Best known is Spanish moss, which festoons the
trees of the coastal South from Virginia to Texas; this plant is used by
the swallow-tailed kite in constructing its beautiful nest. Despite its
name, Spanish moss is actually a member of the pineapple familythe
bromeliads. Bromeliads are the most conspicuous of the park's air
plants. The epiphytic orchids, though less common, are celebrated for
their beauty; their fame, unfortunately, has led to their widespread
destruction. There are also epiphytic ferns, trees, and vines; and one
cactus, the mistletoe cactus, has taken to the air.
Air plants are highly specialized for making a living
under crowded conditions; there are more than 2,000 species of plants
competing for sun and water in southern Florida. The epiphytes have
adapted to the problem of space by growing on other plants. Their roots,
although they absorb some water and minerals, are primarily anchors.
Living in an atmosphere that fluctuates between drought and humidity,
they have evolved several water-conserving tricks. Some have a reduced
number of leaves; others have tough skins that resist loss of water
through transpiration; still others have thick stems, called
pseudobulbs, that store moisture. The bromeliads are particularly
ingenious: many have leaves shaped in such a way that they hold
rainwater in vaselike reservoirs at their bases. Mosquitoes and tree
frogs breed in these tiny reservoirs, and in dry periods many aboreal
animals seek the dew that collects here.
COMMON BROMELIADS. (click on image for an enlargement in a new window)
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Most of the orchids and bromeliads grow in the dimly
lit tropical hardwood hammocks and cypress sloughs. A few species,
however, having adapted to the sunlight, live on dwarf mangroves and the
scattered buttonwoods, pond apples, willows, and cocoplums of the
glades. The butterfly and cow-horn orchids are sun lovers, as are the
twisted, banded, and stiff-leaved bromeliads. All have adapted to the
sun with dew-condensing mechanisms or vases at the bottom of the
clustered leaves.
One tree, the strangler fig, starts as an epiphytic
seedling on the branches of other trees. Eventually, however, it drops
long aerial roots directly to the ground or entwines them about the
trunk of the host treewhich in time dies, leaving a large fig tree
in its place.
Of all Everglades plants, the epiphytic orchids are
most fascinating to mana fact which largely explains their decline. Of
some 50,000 species around the world (the orchids being one of the
largest of plant families), the park has only a few. Fire, loss of
habitat due to agriculture and construction, and poaching by both
commercial and amateur collectors have brought about the extermination
of some and have made others exceedingly rare. Some are rare because of
special life requirements. For example, a few must live in association
with a certain fungus that coats their roots and provides specific
nutrients.
The largest orchid in the park is the cowhorn, some
specimens of which have weighed as much as 75 pounds. Unfortunately,
this orchid has been a popular item for orchid growers and collectors
and is becoming rare in Florida. Poachers have practically eliminated it
from the park. Recently Boy Scout friends of Everglades salvaged many
orchids from hammocks about to be bulldozed for the jetport. By
laboriously tying them to trees in the park, they assured the survival
of the plants.
SHOWY ORCHIDS OF THE HAMMOCKS AND TREE ISLANDS. (click on image for an enlargement in a new window)
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The night-blooming epidendrum is perhaps the most
beautiful of the park's orchids. It is widespread and fairly common in
Everglades, occurring in all ecosystems. Flowering throughout the year,
it bears its white, spiderlike blossoms, 2 inches across, one at a time.
It is especially fragrant at nighthence its name.
Epiphytic orchids have the smallest seeds of any
flowering plants. Dustlike, they travel far and wide on the air; it is
believed that over eons all species of Florida orchids arrived on the
wind from South America and the West Indies.
The giant wildpine is a spectacular bromeliad that
grows on the sturdy limbs of buttonwoods, spreading to 48 inches and
developing a flower stalk 6 feet long.
Of the approximately 20 species of epiphytic ferns in
the park, the most common is the curious resurrection fern. Sometimes
called the poor man's barometer, it has leaves that in dry weather curl
under and turn brown but with the coming of rain quickly unfold and turn
bright green, making instant gardens of the logs, limbs, and branches on
which they grow.
Watch for the air plants (as well as the trees and
other wildflowers) that have been labeled along the trails and
boardwalks. You will be able to examine some of them closelybut leave
them unharmed for future visitors!
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