THE VARIOUS GROUPS OF PLANTS 



6i 



Fig. 17. — Various types of Ferns (Filicineae). A, Shield-fern (Dryopten's) 

 ( ■; i); B, a group of Tree-ferns, Cyathea (scale indicated by man in foreground); 

 C, Pteris longifolia ( ,< vo); D, Moonwort {Botyychiut)i) ( < about ^); E, Common 

 Adder's-tongue (Ophioglossum vulgatum) (x about h); F, a Water-fern (Marsilea) 



( < about I). 



of many Ferns also propagate vegetatively — for example, when the 

 old parts of types with branching rootstocks die off and fragmentation 

 results, or through the growth, after detachment, of special bulbils 

 or plantlets that develop on the leaves of some species. 



