24 BOTANICAL GAZETTE [jantjaey 



ase previous to the disappearance of the membrane is not sjood 



countino;, because of the curved and twisted 



somes. 



metaphas' 



STOSS 



chromosomes are in irre£rular arrangement 



pole, accurate counting is always possible. 



From the counting made in the stages mentioned above, the write: 

 believes that there is a constant number of chromosomes in Ne 

 phrodium, i. e., 128 or 1.^2 in tvpical mitosis and 6a or 66 



m 



reduction division; 



in harmony 



6) in 



The reason for the presence of two sets of numbers of chromosomes 

 ch as 64 or 66) has not been determined. 



Conclusion 



Since this study of sporogenesis was carried through as preparatory 

 for the study of apogamy in Nephrodium, the general conclusions will 

 appear in the final paper. Two points, however, may be summarized 

 here: (i) there is uniformity in the number of chromosomes in the 

 sporophyte ; and (2) in the normal life-histor>' there is a reduction of 

 chromosomes in sporogenesis. 



The University of Chicago 



LITERATURE CITED 

 1. Atxes, C. E., Chromosome reduction in Lilium canadense. Box. Gazette 



1904 



2. 



pott 



3. - 



Botany 19:189-258. ph. 6-g. 1905. 

 as Verhalten der Kernsubstanzen wahrend der Synapsis 

 rzellen von Lilium canadense. Tahrb. Wiss. Bot. 42 



AZirTTE 



p. 2. 1905. 



4- Ate&sok, G, F., Studies on reduction 

 f^s. 1-6. 1899. 



5- Bel\jepf, W., Ueber die Reduktionstheilung des Pflaiuenkems. Ber. 



Dentsch. Bot. GeseDs. 16:2 7-34. figs. i-it. tS^. 

 6. Eerghs, J., Formation des chromosomes het^rotj-pkities dans k sporo^^ 



" ^tale. L Depnis k spnrteie jtami*a«x chromcsonies mtis dans 



micrroporogenese d^AUmm fisiid^sum et ^ Lilmm landfdium (spedosum 

 La Cellule 21:1 73-1S9. fi. x. 1904. 



