DEFINITIONS OF TERMS. II 



be the trunk ; for, though the upper parts of the fronds 

 die away, they leave the lower parts as contributions to 

 the stem. 



How beautiful are great tree-like forms of ferns 

 (page 10) can only be fully appreciated by those who 

 have seen these exquisitely-beautiful inhabitants of 

 tropical forests in their native habitats. 



The only British species that, in character, at all re- 

 sembles a tree-fern is Osmunda regalis, which forms a 

 trunk sometimes two feet in height. 



From the upper parts of the stems of ferns rise the 

 fronds, the name given to their leafy parts. The term 

 frond will be here used to mean the leafy part and the 

 long or short stalk which supports it and connects it 

 with the crown. This stalk is called the stipes ; but, 

 when reference is made to the shape of the frond, it 

 must be understood that only the leafy part is re- 

 ferred to. 



In the ensuing illustration (page 12) of the Lady. Fern 

 (Athyriumfilix-famina) the leafy part is shown separately 

 from the scaly stipes on- the right-hand side. 



The mid-stem of the frond, continuing from the stipes 

 into the leafy part, is called the rachis. If this be 

 branched, the principal or central mid-rib is the primary 

 rachis and the branches are the secondary rachides. 



If the frond assume the form of a single leaf with an 

 unindented margin, it is said to be simple. The term 

 entire is used to refer to an unindented margin. 



In the figure, on page 13, of the Adders-tongue 

 (Ophio gloss Jim vulgatum) the oval leafy part illustrates 

 what is called an entire margin. 



When the frond is like a single leaf with incisions 

 which, though deep, do not reach down to the rachis, it 

 is described as being pinnatifid. Such is the form illus- 

 trated by the Scaly Spleenwort on page 6. If the in- 

 dentations reach the rachis, leaving it bare, the frond 

 become s pinnate, and each separated leafy part is called 



