liKj depress i oil or pil- clesci-ibecl by Rrsso ■ (*??). Tjio 

 maci-OGpoivjirjivjii mo. iu..- collu pusn ou:. in o uiiio c;.viL.:; 

 (ma. - sp.r.i.c, Fi^a. To, o), far beyond the microspo- 

 nu^gimi mo. her calls mid sv/oll to many uimcs :^ij.eir orif^i- 

 nal siiJ3. For this reason sagittal sections alittlc near- 

 er t}ie medi:"a"L v:all tuan uiat shovm in Fi-. '"~ oald not 

 sliov/ anyth.ing of the micrcs"nor?n2iiiin mother cells, but 

 simply ■' he soral cavity cuiu Uie two layers ot the Indus i"..''m, 

 on each, side of th.e macrosporanf^inm mothei' cells, and the 

 microsporangiujn motlier cells might thus easily bo ove - 

 looked. 



As the macrosporangiiim cell grov/s and sv.'^ells laterally 

 to a v/edge like form, v/ith a rornded enter end, it ir. also 

 pushed out into th.e soral cavity, by the grov/th of the 

 plerone cells of the a.croscopic part of th.e basiscopic 

 half of section VI (:.:..b.. Figs. 58, 80), Meant ii- 

 microsporangium mother cell on each side has increased 

 in thiclcness and divided by ari an iclino parallel to the 

 segment •.'all (ni - sp.m.Ce, F-^'r;. ''O), th.en eacli of the 

 resultin- cells divides by a similar v/all (Fig, 6l) c-nd 

 thus foiii' cells fjro formed on :'ach aid- o ' tlio rnac'ospo- 

 rangi".xi motlier cell. These are pusiied around by the grov/t;. 



of 'he macrosporLUigium motlier cells to a position ne' '1 " 

 at right angles to their original one (Fig. 82). Tliese arc 



