I4 g BOTANICAL GAZETTE [march 



appeared. However, the problem concerning the nature of the 

 blepharoplast and its relation to the centrosome, not only in pterido- 

 phytes but in various groups of plants, has been discussed by Stras- 

 burger (87, with a critical review of the works on this subject), 

 Dangeard (21, on algae), Timberlake (89, on algae), Webber 

 (96, on Zamia), Ikeno (45, on Marchantia; 46), Davis (24), and 

 some others. 



Oogenesis in pteridophytes has not aroused as much interest as 

 spermatogenesis. Oogenesis in Filicales has been observed in vari- 

 ous forms by Janczewski (49), Goebel (29), Brixton (9), Camp- 

 bell (15), and many others. 



Morphological investigations of the processes of fertilization in 

 pteridophytes have been published by Strasburger (83, on Pteris 

 and Ceratopteris), Hanstein (33, on Marsilia)), Campbell (13, on 

 Pilularia; 14, on Osmunda), Shaw (79, on Onoclea), and Thom 

 (88, on Adiantum and Aspidium). A few points of cytological interest 

 in their studies concerning fertilization in pteridophytes may be sum- 

 marized as follows : 



In his paper on Osmunda, Campbell writes that in several in- 

 stances, when the archegonium seemed about ready to open, an 

 appearance was observed that looked very much like the formation of 

 a true polar body, and was not to be compared with the ventral canal 

 cell. He suggests that this structure, like the polar body, may be 

 derived from the division of the nucleus of the egg, his reason for 

 the suggestion being the apparent diminution of the nucleus of the 

 mature egg at the time of the appearance of the structure, although 

 actual division was not observed. 



In Onoclea Shaw states that before the archegonium opens, the 

 egg is depressed above, and the nucleus of the egg is flattened, due to 

 the pressure caused by the swelling of the wall of the ventral canal cell. 

 As soon as the archegonium opens and the disorganized contents of 

 the neck canal cells are expelled, the egg becomes turgid. After the 

 sperm has entered the egg at the receptive spot, the egg collapses, and 

 he suggests that this prevents the penetration of more than one 

 sperm. Mottier (67) expressed some doubt whether the collapsed 

 appearance is really normal. 



In Pteris Strasburger (83) observed the formation of a mem- 



