Fig. 207. —A Fern (Aspidiitm Filix-mas). 

 1, general view of tlie plant; a, young fronds unrolling; 2, cross-section of the 

 rootstock, showing tihro-vascular bundles, a a; 3, a pinnule with fruit-dots ; 

 a a, indusiuin ; b, spore-cases ; 4, vertical section through 3 a ; 5, vertical section 

 at right angles to that of (4), showing : a, section of pinnule of leaf ; b, section of 

 indusium ; c, spore-cases ; 6, a single spore-case, with its stalk, a, and its elastic 

 ring, c, discharging spores at d. {1 is reduced to about ^ natural size ; 2, 3, are 

 sli^tly magnified ; 4 is more magnified j 5, 6 are considerably magnified.) 



