84 



VASCULAR CRYPTOGAMS 



there are species with barren and fertile leaves, differing from one 

 another in habit and in degree of segmentation ; in other heterophyllous 



FIG. 58. Sori of Polypodiaceac (variously magnified), a, b, Adiantunt ; c, Lindsaya ; <i, e, Blechnum ; 

 f*g> Cystopteris ; h, i, Da-vallia ; k, /, Cheilanthes ; tn, , Pteris ; o,fl, Woodwardia ; q, Scolopen- 

 drium; r, s, Asplenium; t, Aspidium ; u,v } Woodsia; w, Gymnogramme ; x, z, Polypodium. 

 (After Luerssen.) 



ferns (species of Polypodium) both forms of leaf are fertile. A few of 

 the Polypodies are arborescent (Dicksonia L'Herit). 



