LIFE HISTORY OF A FERN 



153 



coiled up from the tip. As the leaves grow they unroll, 

 and in some ferns, at certain stages, they often closely re- 

 semble the neck of a violin (Fig. in). The leaf -blade 

 possesses veins of nbro-vascular bundles that pass down 



FIG. 112. Portions of the sporophylls of two ferns to show the sori. 

 On the left Poly podium pundatum (L.)Sw.; on the right a variety of Pteris 

 longifolia, with sporangia marginal on the pinnules. 



the leaf-stalk and through the stem to the roots. Because 

 of the possession of these vascular bundles, ferns (and 

 all other plants of which this is true) are called vas- 

 cular plants. These leaves perform all the functions 



