104 BOTANICAL GAZETTE Iaugust 



Wolfe (94) found in his study of Nemalion that the spindle 

 poles are always occupied, except possibly in the antheridial mi- 

 toses, by two heavily staining bodies which he considers centro- 

 somes. They are surrounded by hyaline areas 'and apparently 

 divide, but no radiations are present. 



In Polysiphonia (Yamanouchi 96) there are during the pro- 

 phases of every mitosis two centrosome-like bodies in the kinoplasm 

 at opposite poles of the nucleus. A little later the small bodies 

 disappear, while the kinoplasm takes the form of large centrosphere- 

 like structures without radiations. During the late anaphases these 

 become indistinguishable. Yamanouchi believes that these struc- 

 tures are not permanent cell organs, but are formed de novo at the 

 beginning of each mitosis. 



In the tetraspore mother cell of Corallina (Davis 19, Yama- 

 nouchi 99) two deeply staining masses, or centrospheres, occur at 

 opposite ends of the nucleus during the prophases of karyokinesis. 

 They occupy the spindle poles and are surrounded by radiations. 

 During the later anaphases they disappear and are formed de novo 

 at the next division. No true centrosomes are present. 



Among the fungi the best known centrosomes are those of the 

 Ascomycetes. Harper (40, 41, 42, 43) has described in the asci of 

 Peziza, Ascobolus, Erysiphe, Lachnea, P hyllactinia , and other genera 

 granular disc-shaped centrospheres surrounded by asters at the 

 poles of the spindle. He regards them as permanent organs of the 

 cell. Guilliermond (37, 38) shows the presence of centrosomes 

 and asters in several other genera. Especially interesting is the 

 account of Gallactinia succosa given by Maire (62) and later by 

 Guilliermond (39). In the ascus of this form a single centrosome 

 arises within the nucleus with a cone of fibers extending toward the 

 chromatin. It divides to two which take up positions 180 apart 

 at the nuclear membrane, at which time asters develop in the cyto- 

 plasm. Faull (26) found that in Hydnobolites a large centrosome 

 appears outside the nucleus during the prophases of karyokinesis. 

 In Neotiella the spindle terminates in minute centrosomes with 

 astral rays very faint or absent. In Sordaria he describes the 

 centrosomes as disc-shaped while the cell is in the resting condition 

 and round and smaller during division. The formation of the 





