REPRODUCTION OF THE FERN 



123 



but, like the hydroid, it gives rise without fertilization to an 

 organism different from itself. These dissimilar organisms are 

 formed from spores which develop on the under surfaces of the 



FIG. 49. Development of a fern (Aspidium) sporangium, a, The young spor- 

 angium-forming cell just divided from its parent epidermis cell; b, c, d, e, f, 

 different aspects of the dividing cells of the spore capsule; g, origin of the tapetal 

 cells and formation of the spore-producing cell or archesporium (ar); h, increase 

 of the tapetal cells (i) and formation of the spore mother cells; i, j, k, further 

 stages in the development of the sporangium; an, annulus; pd, pedicel. (From 

 Sedgwick and Wilson.) 



