Download Imagine you are walking through a tropical rain forest. The air feels

Imagine you are walking through a tropical rain forest.
The air feels warm and damp. You hear insects buzzing and
birds calling. You brush against a small, green, feathery
plant. As you look around, there are lots of
these plants growing on the forest floor.
The plants described above are called
ferns. There are many different kinds of
ferns. They range in size from low-lying
plants that can cover a forest floor to tree
ferns that can grow very tall. Some tree
ferns can grow up to 25 meters tall!
Ferns have green leaves that are sometimes
called fronds. Each frond is divided into
smaller parts called leaflets. Leaflets look
like tiny leaves, and they give ferns a
feathery appearance. Many ferns grow in tropical rain forests
where the environment is very moist. However, some ferns
grow in cooler rain forests or areas where the seasons
change. Some ferns can even grow between rocks!
Now imagine again that you are in a tropical rain forest.
You step closer to a fern to get a better look at it. You see lots
of tiny brown spots on the leaves. Don't worry! These spots
are not from a plant disease. They are sacs that hold plant
parts called spores. Ferns produce clusters of spores instead
of seeds. The clusters are often arranged in rows on the
undersides of the leaflets. When the time is right, the spores
break out of their sacs. They are carried by wind or water to
new locations. If spores land on moist ground, they may
grow into new fern plants.
Ferns were once the main plant in ancient forests. They have
been around for millions of years and can still be found in
many places on Earth.