4 BOTANICAL GAZETTE [january 



apogamy " 



which will appear later. Much attention has been paid to the behavior 

 of chromosomes, combining observations with theoretical views, with 

 a hope of securing an explanation of the phenomena observed, so 

 that the chromatin substance will be the chief object treated in the 

 present paper. 



I -^ish to express my gratitude to Professor John M. Coulter 

 and Dr. Chl\rles J. Chamberlain for their kind advice and criticism 

 during the progress of this work. I am also under obligation to other 

 members of the botanical staff for rnnrtp<;iVc; pvtpndprl tn mr^ 



MATERIAL AND METHODS 



The material for this investigation was collected in greenhous 

 of the Hull Botanical Laboratory, and in Lincoln and Washingtc 

 parks, Chicago, from October 1906 to March 1907. 



Killin 



among 



lemming's weak solution, with a little modification in the percentage 



most 



fluid for two to 



as 



the same 



formula, but without osmic acid, ten to twenty hours. The 

 thoroughly washed material was passed very carefully through 



48° to 52° paraffin 



begin 



and imbedded in 

 in thickness and 



alum-hematox\din 



times combined with counter-stains, such as safranin, orange G, cosin, 

 or Congo red. A Zeiss apochromatic immersion 1.5"^™, N.A. 1.30, 



compensating oculars 



DESCRIPTION 



porophy 



too 



in vegetative mitosis. The form of the mitotic figu 



affected by irregularities in the size of the cell which contains 

 the abundance of plastids, oil, and other cell contents 

 what with accurate observation. The mitotic figu 

 during the formation of sporogenous tissue, from 1 



(rf the " 



tiii 



hesporial cell to the completion of spore mother 



