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 
of ferns.

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.

Ferns 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 
plant develops.

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.

Ferns 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 
enjoy them".