50 WHERE TO FIND FERNS. 



V. THE BRACKEN. 



Pteris aqnilina. 

 (Plate XL, Fig. i, page 69.) 



LENGTH OF FROND. One foot to twelve feet, ac- 

 cording to the more or less favourable conditions of 

 growth. The maximum and minimum lengths given 

 are both exceptional ; for, as ordinarily seen, this fern is 

 from two to six feet long. 



GENERAL DESCRIPTION. Roots few in number, 

 fibrous, but somewhat fleshy, attached, along its entire 

 length, to the rhizoma. Rootstock, a rhizoma brownish- 

 black in colour, soft, and thickly covered with short 

 hair extending itself both horizontally and perpen- 

 dicularly ; sometimes penetrating to a depth of more 

 than a dozen feet. Fronds deciduous, ordinarily tri- 

 angular in shape, the leafy part about twice the length 

 of the stipes : bipinnate in small specimens ; tripinnate 

 in larger ones. The tripinnate may be said to be the 

 normal form. Pinnae, placed in nearly opposite pairs 

 along the rachis, and more or less acutely lance-shaped ; 

 pinnules acutely lance-shaped, pinnate in the lower part 

 (of tripinnate fronds), pinnatifid higher up, and more or 

 less entire at the frond apex. Lobes oblong and blunt- 

 pointed. Towards the apex of the frond the pinnules 

 are dwindled to mere lobes ; nearer it the pinnae are 

 also lobe-like, and a lobe terminates the frond. Lobes 

 concave on their undersides. Fructification marginal, 

 the lines of spore-cases being enclosed in double 

 indusia formed by elongations or distensions of the 

 cuticle or membranous surface of the lobes. 



HABITATS. Open commons, downs, and heaths ; 

 glades ; woods ; hillsides and streamsides ; hedgebanks 



