DEVELOPMENT OF SPORANGIA. 



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FIG. 65. (After Luerssen.) Development of the sporangia of Azpidnim Fili.r mas, 

 which is closely similar to that of Pteris. a, the young sporangium standing 

 upon the epidermis-cell from which it has just been divided ; .r, the proximal 

 cell cut off from the sporangium to form the pedicel and support the capsule ; 

 a, 1, the first partition in the capsule ; ft, 1 and 2, the first and second partitions; 

 c, 1, 2, 4, the first, second, and fourth partitions ; cl and e are cross-sections of the 

 capsule showing the oblique position of the partitions, and especially that of the 

 third ; /, a later stage ; g, the origin of the tapetal cells and the formation of the 

 archesporium ; 7i, division of the tapetal cells and the formation of the spore 

 mother-cells ; Z, four spores as they originate in the spore mother-cells : /, ./, ft, 

 the annulus and ripe sporangium, in surface view ; p, peripheral cells; ar, 

 archesporium ; t, tapetal cells; an, annulus. 



