EQUISETALES (HORSETAILS) 435 
Some Plants Resembling True Ferns. —Some plants which 
resemble the True Ferns, although they belong to another group, 
are the Botrychiums or Moonworts that are common in the woods 
(Fig. 388). They have an underground stem which sends up 
leaves that have a finely divided vegetative portion and a spore- 
bearing portion that much resembles clusters of small grapes. 
Fic. 389. — A section through the tuber-like gametophyte of Botrychium, 
showing one archegonium and a number of antheridia in the upper surface. 
X about 10. 
It is, however, in their gametophyte generation that they differ 
most from True Ferns. Their gametophytes are tuberous sub- 
terranean structures bearing the sex organs on the upper surface, 
and associated with the gametophytes there is always an 
endophytic Fungus (Fig. 389). 
Equisetales (Horsetails) 
In ancient times, as shown by their fossils in coal and other 
kinds of rock, the Equisetales were very abundant, but the only 
surviving group is the Horsetails. Their slender stems, often 
called Joint Grass, are common in meadows, in moist places in 
the woods and along roadsides. There are about 25 species of 
Equisetum. There is Equisetum palustre common in swamps, 
Equisetum pratense and Equisetum arvense common in meadows 
and fields, and so on. Those growing in meadows and fields 
are often troublesome weeds. They are widely distributed over 
North America and also occur on other continents. They range 
in height from a few inches to several feet. It is reported that 
one form in the West Indies and Chili sometimes reaches a height 
of 40 feet, but in our region 3 or 4 feet is a good height. The 
Equisetums are also called Scouring Rushes because their stems 
contain silica which is used in making scouring powders. 
