THE VASCULAR CRYPTOGAMS 



57 



FIG. 28. A, transverse section of portion of lamina of Male Fern 

 passing through a sorus ; i, indusium. Magnified 80 

 diameters. , single sporangium in side view ; a, annulus ; 

 st, cells which dehisce ; d, glandular hair. C, sporangium - 

 dehiscing at st ; a, annulus. B and C magnified 100 dia- 

 meters. D, spore mother-cell divided (only three spores 

 visible). Magnified 350 diameters. E, nearly ripe sporan- 

 gium. F, young sporangium ; c, sporogenous cells ; iw, 

 tape turn ; w, wall. (7, very young sporangium, showing first 

 divisions. Magnified 260 diameters. (After Luerssen.) 



