T 62 BOTANICAL GAZETTE [march 



plast in Derbesia, in which the blepharoplast arises from the granules 

 observed close to the nucleus. There is a time previous to the differ- 

 entiation of the zoospore when the nucleus lies close to the cleavage 

 furrow that finally separates the adjacent zoospore rudiments. Close 

 to the nucleus he observed a number of granules which migrate toward 

 the surface region of the protoplast of the zoospore and assume a ring- 

 shaped arrangement. By the fusion of these granules the blepharo- 

 plast is established. 



According to these results, excepting Strasburger's on Vauchcria, 

 Cladophora, and Oedogonium, the blepharoplast seems to originate 

 in the interior of the cytoplasm (Cycas, Ginkgo, Zamia, Equisetum, 

 Marsilia, Gymnogramme, Onoclea), sometimes from a position close 

 to the nucleus (Adiantum, Aspidium, Hydrodictyon, Polytoma, Der- 

 besia), and in still another case from the interior of the nucleus 

 (Marchantia). 



In Nephrodium, as has just been described, the mitoses which occur 

 within the antheridium were all investigated, from the first sperma- 

 togenous cell until the final differentiation of the spermatid. The 

 blepharoplasts were demonstrated by the differentiation of stains as 

 two small deeply staining bodies appearing first within the cytoplasm 

 of the spermatid mother cell. The nucleus of the spermatid mother 

 cell is in the resting condition when these bodies appear, and during 

 the mitosis which differentiates the spermatid the blepharoplasts are 

 situated near the pole of the spindle. After the telophase one bleph- 

 aroplast accompanies each daughter nucleus and there is estab- 

 lished a spermatid with a single blepharoplast. Sometimes blepharo- 

 plasts appeared in spermatogenous cells of the four-celled stage of the 

 antheridium, but it is certain that these four cells do not represent 

 spermatogenous cells in an early stage previous to the formation of the 

 spermatid mother cells; on the contrary, they are in this case real 

 spermatid mother cells, the number of sperms produced in the anther- 

 idium then being only eight. 



The relationship 0] the blepharoplast and the centrosome. — The 

 centrosome in pteridophytes was figured first by Humphrey (ii) and 

 then by Calkins (39) in the spore mother cells of such forms as 

 Osmunda, Psilotum, Adiantum, and Pteris. One year after Calkins' 

 paper appeared, Shaw's account (80) of Marsilia and Onoclea was 



