XXXli INTRODUCTION. 



apex; this will be seen in the large or expanded 

 frond at page 13, in the erect frond at page 12, and 

 in the frond at page 48 ; this main stem is called the 

 rachis. The branches on each side of this rachis are 

 called pinnce ; at page 12, the frond is pinnatijid, the 

 pinnae not being quite separated from each other; 

 the little fronds at page 30 are called pinnate, because 

 the pinnae are quite separated ; in the frond at page 48 

 the pinnae are not only quite separated, but they are 

 also deeply divided. The pinnae of the frond at page 13 

 are divided into a number of branches on each side ; 

 the branches are pinnulce. The pinnulae are again 

 divided into lobes. 



The seeds of ferns are not preceded by any visible 

 flowers ; they are generally produced on the back of 

 the frond in capsules, called thecce ; these thecae are 

 clustered together in little masses, and are situated 

 on the veins in the divisions of the frond; see the 

 figure at the top of page 45, where it will be observed 

 that each mass has a small white kidney-shaped spot ; 

 this is intended to represent a white membranous 

 substance, something like a portion of the cuticle of 

 the frond, and is called the indusium. 



While this Work has been in progress, I have 

 received the most kind and valuable assistance from 

 some of our most distinguished Botanists ; and I beg 

 to assure the gentlemen whose names appear below, 

 how all-important to one unskilled in the science 

 their services have been, and to return them my 



