INTRODUCTION. 13 



the entire frond, is simple. In some other species we shall 

 find it is branched, and this branching of the rachis plays an 

 important part in producing the great variety of form in the 

 fronds ; at the same time it should be noted that even with the 

 simple rachis a good deal of variety is attained. For example, 

 in the Ceterach we get an entirely different-looking frond by 

 the simple expedient of notching the margins almost to the 

 rachis. A similar arrangement is seen in the Common Poly- 

 pody, but in the Hard Fern there is a slight advance, for whilst 

 the upper notches fall short of reaching the rachis, the lower 

 ones are cut right up to it. A frond completely divided into 

 a number of lobes symmetrically arranged is wing-like or 

 pinnate, such as we find in the Maidenhair Spleenwort ; but 

 as in the Ceterach and the Polypody the lobes are not quite 

 separate, they are only regarded as cut in a pinnate manner, 

 and the frond is therefore pinnatifid. The Male Fern affords 

 us an example of a distinctly pinnate frond in which the pinnae 

 (as the primary divisions are called) are themselves either pin- 

 nate or pinnatifid. If pinnate the whole frond is said to be 

 bi pinnate. The frond of Royal Fern is also bipinnate ; whilst 

 that of the Brack jn is either tripinnate or quadripinnate (3 or 

 4 times pinnate). Fronds that are divided to this extent are 

 also referred to as decompound (Plate 6). 



In early spring, when first the annual renewal of activities 

 begins to manifest itself outwardly, the crowns of those species 

 with tufted rootstocks are worthy of attention. There the new 

 fronds will be found neatly coiled up and packed together, each 

 clothed with chaffy scales which have protected them during 

 the winter. If one of the more advanced of these frond-buds 

 be broken off and unrolled, it will appear as though a previously 

 expanded frond of very thin and delicate texture had been 



