290 



RHIZOME 



[e.g. Bracken). In the creeping forms, t|he leaves usually arise in 

 a row, on either side, and are separated hiy well-marked internodes 

 (Fig. 158, B). In short-stemn-ied species, however, whether the 

 rhizome be erect or inclined [e.g. Male Shield, Fern, Nephrodiumfilix- 

 mas 1) , the leaves are densely crowded, and^ show an obvious spiral 

 arrangement. In the more compact formSj a conspicuous feature 



Fig. 158. — The Bracken (Pleris aqiiilina). A, Diagram of transverse seiotion 

 of rhizome. Scl., sclcrencliyma ; St., steles. B, Rhizome shewing 

 apex with growing point (g.p.), successively older leaves (I, II, ^III), 

 and the bases of leaves of former seasons. C, Yoimg frond. 1 



of the rhizome, which adds appreciably to its apparent thickn.ess, 

 are the adhering bases of the leaves, which persist after lanidna 

 and petiole have died away. All the roots of the adult Fern 

 are adventitious (Fig. 158, B) ; they usually arise in the neigh- 

 bourhood of the leaf-bases, and are gcnerall}- black in colour 

 and forked. 



Fhe young leaf is mostl}- more or less densely clothed with 

 ' y\lso kn(jwn as Aspi dtiiDi fili.x-iiias and LastrcFa filir-iiias. 



