THE PTERIDOPHYTES. 187 



Underwood describes 158 species in " Our Native Ferns 

 and Their Allies." No single locality furnishes a very 

 large number of species. 



The Ferns, in the broader sense, include the True 

 Ferns (far the largest number), the Salvinacece, and the 

 Mars iliac ece. The Marattiacece, or Ringless Ferns, which 

 are exotic, and found only in greenhouses, and the 

 Ophioglossece are closely related. The Ophioglossece, or 

 Adder Tongues, differ from other members of the branch 

 in that the leaves are not circinate in the bud, but are 

 straight or folded, and in their spore cases, which are 

 without rings. They are represented in this country by 

 the Adder Tongues and the Moon worts, Botrychium. 



THE EAGLE FERN. 1 PRACTICAL STUDIES. 



The Eagle Fern (Pteris aquilina), or Brake Fern, is 

 probably the most widely distributed of all the Ferns. 

 It grows in all climates, from the torrid zone to the Arctic 

 circle. It is known to thrive as high as 9000 feet above 

 the sea level. In some tropical countries it is said to 

 reach a height of 12 to 14 feet. In New England 

 it varies in height from a few inches in dry barren 

 localities to three or five feet in rich-soiled moist places. 

 Under favorable conditions it grows in such abundance as 

 to form brakes, or thickets, whence the common name. 



This Fern is easily recognized from the fact that the 

 frond appears to be triply divided. An examination of 

 the frond shows that this is in appearance only, for the 

 two lower branches differ from the pairs above only in 

 size and in being set somewhat forward on the leaf stalk. 

 Specimens for examination should include as much of the 

 underground portions as can be obtained, for it is to be 



1 Practical Studies of almost any other Fern could be added. Any 

 species of Osmunda, Poly podium, or Adiantum would be good. 



