Pteridophytes Filicales 



241 



The portions which are not under water will continue to fruit during 

 the summer and autumn. The whole sporocarp cuts easily in paraffin 

 during the development of sporangia, the division of the spore 

 mother cells, and even during the earlier stages in the formation of 

 spores. Except in the case of the youngest sporocarps, it is better 



FIG. 81. Osmunda cinnamomea: 

 photomicrograph of vertical section 

 of prothallium with an early stage in 

 the development of the archegonium, 

 showing the basal cell, two neck cells, 

 and, between them, the cell which is 

 to give rise to the neck canal cell, the 

 ventral canal cell, and the egg 

 chromo-acetic acid; safranin, gentian- 

 violet; from a preparation by Dr. 

 W. J. G. Land. X425. 



FIG. 82. Osmunda cinnamomea: 

 photomicrograph of a vertical sec- 

 tion with a young archegonium, show- 

 ing the neck canal cell with two 

 nuclei, the ventral canal cell, the egg, 

 and the basal cell chromo-acetic 

 acid; safranin, gentian- violet; from a 

 preparation by Dr. AV. J. G. Land. 

 X293. 



to cut off a small portion at the top and at the bottom to facilitate 

 fixing and infiltration. The mother-cell stage and the young spores 

 will be found in sporocarps which are just beginning to turn brown. 

 In nature, no further nuclear divisions take place within the sporan- 

 gium until the next spring, but the wall of the sporocarp becomes 



