VOLUME XLV 



NUMBER I 



Botanical Gazette 



JANUARY igoS ■ 



SPOROGEXESIS IX NEPHRODIUM 



CONTRIBUTIOISS FROM THE HULL BOTANICAL LABORrVTORY Io6 



Shig£o Yamanouchi 



(with plates i-iv) 



Historical review 



There have been published during the past three decades a few 

 accounts of sporogenesis in pteridophj-tes . Since cytological studies 

 have advanced rapidly in recent years, many views which were once 

 prevalent have been proved to be erroneous, or at least to be capable 

 of a different interpretation, and the authors themselves may have at 

 present entirely different views from those which they held when 

 the accounts were published. It seems worth while, therefore, to 

 make a historical review of some of the work hitherto published. . 



There is first a paper by Humphrey (29) on the study of the spore 

 mother cells of Osmunda, Psilotum, and other forms, in which the 

 main purpose was to prove the presence of extranuclear centrosomes 

 in plants above the br}-oph}-tes. His account of the number of 

 chromosomes in Osmunda was taken up by Strasburoer (46) in 

 his data dealing with the periodic reduction of chromosomes in the 



tiistorj- of organisms, as one of the instances which pre 

 tancy of the number of chromosomes in a certain period 



life 



sterhout's (33) studies on Equisetum were really 



most important contributions to our knowledge of the spore mott 

 cells of hiffher olants. He found that the spindle at the outset 



Strisburger 



multipolar polyarch, according to the terminolog}* of 



(47), and that the numerous cones become grouped around the 



