Ferns are Fascinating
Nature Bulletin No. 633 March 18, 1961
Forest Preserve District of Cook County
Daniel Ryan, President
Roberts Mann, Conservation Editor
David H. Thompson, Senior Naturalist
FERNS ARE FASCINATING
About 390 million years ago, scientists say, some small leafless and
rootless plants became able to live entirely on land. During the next 60
million years, many of their descendants developed into a wide variety
of specialized types described briefly in our Bulletin No. 330 -- Plants
of the Coal Age. Among those new-fangled plants were various types
They were the first plants to have true roots, stems and leaves with a
system of channels, even though quite primitive, for conducting
mineral-laden water from the soil to the leaves; and food,
manufactured in the chlorophyll-bearing cells of the leaves, to all parts
of the plant.
The true ferns and the tree ferns dominated the landscape for the next
175 million years Those we see today in the United States are the
smaller, hardier forms that managed to survive violent disturbances of
the earth's crust and drastic changes in its climates. They retain many
of the primitive features of their ancestors: they do not have flowers,
followed by seeds. Flowering plants, which bear seeds protected by a
fruit or shell, did not appear until the Cretaceous Period, less than 95
million years ago.
reproduce by means of spores that are contained in tiny sacs
called sporangia On many kinds of ferns, groups of these sporangia
appear as brown dots on the under side of the fronds (leaves); on
others they form clusters in berry-like masses on separate stalks. Each
sac is filled with hundreds of microscopic spores that resemble dust.
When the spores are ripe, the sac opens and those that fall or are borne
by wind to shaded, damp soil develop into flat, heart-shaped, green
organisms -- about 1/10th the size of a dime -- each called a
prothallium. On the under surface of it are male and female organs
that produce sperm and "egg" cells If water is present -- dew will do --
the sperm swims to an egg and enters it. From this union the leafy fern
Most of the true ferns are thin in texture and thrive best in moist shady
places. Of several thousand species in the world, by far the greatest
number occur in tropical rain forests. They attain greatest size and
luxuriance in Brazil, Ceylon and New Zealand. Some of the tree ferns
become 30 or 40 feet tall, with fronds 15 feet in length.
In our country, most kinds occur in deep moist woodlands, ravines,
rock gorges, and on ledges near waterfalls. The scarcity of suitable
habitat explains why only 36 species and subspecies have been
recorded in the Chicago region Thanks to "progress" and plundering
people, several of those have become extinct.
Some kinds, however, are adapted to live in drier or even arid
conditions Among those found in old fields, open woodlands, or along
roadsides, the Lady Fern is common in Cook county. Chiefly in open
woodlands, we have the Brake Fern or Bracken. Of all ferns, it is most
widely distributed over the earth and one of the few used by man for
food, medicines, bedding, etc.
In your forest preserves the Maidenhair Fern and the unique Walking
Fern can be found. Among the more fernlike kinds, the Fragile Fern is
the smallest and the Ostrich Fern is perhaps the finest. In, or at the
edges of marshes we have the Sensitive Fern, Royal Fern and, largest
of all, the Cinnamon Fern.
are fascinating. You usually find them in fascinating places --
far from beaten paths. But when you do, please remember and obey
our wildflower slogan: "Love 'em and leave 'em, so that others may
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Update: June 2012