2 BOTANICAL GAZETTE [JANUARY 



w 



m 



* 



common axis, but the poles of the spindle at metaphase hold their 

 composite nature with entire absence of the foral renfor nr r^ntrn. 



some 



much 



that the development of the spindle in higher plants is controlled by 



centrosomcs, is noteworthy. 

 Tlicn appeared 



and 



'Somes: one by Calkins (ii) 



(44) on Pteris aquilina, Cystopieris fragilis, and Scolo pendriu 

 vulgare. Calkixs believed that there was a tetrad 



'as a tetrad formation of 

 mother cell of ferns, and 

 forms followed the same 



as 



animals, with 



L transverse division and consequently a qualitative 

 EiSMANN's sense. Stevens' studies on the forms 



m 



obsen 



main pomt being that there is present no t 

 mosomes in the spore mother cell, but two long 

 therefore there is merely a quantitative reductioi 

 tion on the formation of daughter chromosomes 

 was criticized by Strasburger (47;. 



Smith (42) investigated the sporogenesis of Osmumla regaUs. 

 His results agree with those of Osterhout in regard to the absence 

 of centrosomes, and differ as to the origin and develonment of the 



spindle ; 



paper (26 



bipolar from the beginnin 



account 



the sporogenesis of eight genera of ferns, i. e., Pteris, Scolopendrium, 

 Asplenium, Onoclea, DavaUia, Fadyenia, and two other forms among 

 Cytheaceae, and seems to confirm Farmer and :vIoore's interpreta- 

 tion (i8j of the formation of chmmmnmoc ^f tK^ i,„f ^ • j- .r^- _ 



'O 



occurrence 



formation of Botrychium virginianum. 



published his results on the spore 



account 



the spore mother cell ; the first 

 and second divisions, he finds 



nucleus. As regards the heterotypic mitosis, he states that the 



chromosomes in metaphase separate in the line of transv 



