74 BOTANICAL GAZETTE [JANUARY 
work conducted wholly in the artificial conditions of the laboratory or green- 
house.— H. C. Cow es, ; 
IKENO has published his full account of spermatogenesis in MJarchantia 
polymorpha,” following his preliminary announcement in the Comptes Rendus. 
He finds a centrosome beside each nucleus previous to the mitoses in the 
spermatogenous tissue. The centrosome divides, and its products, passing 
to opposite sides of the nucleus, become the poles of the spindle. He gives 
evidence that the daughter centrosomes sometimes divide again when at the 
poles of the spindle in anaphase. The centrosome cannot be found at the 
side of the daughter nucleus after the mitosis is completed, but it appears 
when the nucleus is ready for the next division. Ikeno believes that the 
centrosome is formed within the interior of each nucleus as a deeply staining 
body among the linin threads. This body moves to the nuclear membrane 
and is thrust from the nucleus. Outside of the nucleus it becomes the centro- 
some, functioning in the mitosis as described above. This account of the 
After the final mitoses in the s ermatogenous tissue the centrosomes 
remain, to become the blepharoplasts of the sperms. Each blepharoplast 
‘passes to the plasma membrane of its sperm cell and develops two cilia. 
There is formed at this time another deeply staining body in the cytoplasm 
view are Webber, Strasburger, and Shaw, who hold that there is no genetic 
relationship between the blepharoplast and the centrosome. The opinions of 
these authors cannot be discussed in a brief review, but the problem rests on 
all of the great groups of plants, 
to the complications of spermato 
bility of cell studies of this character.— B. M. Davis 
ITEMS OF TAXONOMIC INTEREST areas follows: THEo, Hotm (Am. Jour. 
Sci. IV. 16: 369-376. 1903), has made a morphological and anatomical study 
of Hypericum virginicum, often called Elodea, and has reached the conclu- 
sion that it represents the obscure but valid genus Triadenum of Rafinesque- 
Accordingly he writes the name Triadenum virginicum (L.) Raf.— THEO. 
“*IKENO, S., Die Spermatogenése von Marchantia polymorpha. Beihefte Bot- 
Centralbl. 15 : 65-88, pl. t. 1903. 
