The Fertilization of Pythium de Baryanum. 
BY 
KIICHI MIYAKE, M.A, 
With Plate XXXVI. 
P RINGSHEIM (’58) was the first who observed the pheno- 
mena of fertilization in Pythium . He found that in 
Pythium monospermum, the antheridium sends out a process 
into the oogonium, while the contents of the latter separate 
from the wall and accumulate info a spherical mass, the 
oosphere, which he calls the ‘ Befruchtungskugel.’ After 
the fertilization-tube reaches the oosphere, it discharges its 
contents through the opening at the apex. He believed that 
very minute spermatozoid-like bodies in active motion were 
found in the antheridium. Cornu (72’) observed the passage of 
the antheridial contents into the oogonium in Pythium gracile 
and P. Cystosiphon, but he denied the presence of sperma- 
tozoid-like bodies in the antheridium. After that De Bary 
(’81) made more careful studies and found that, in several 
species of Pythium , soon after the formation of the fertiliza- 
tion-tube the protoplasm becomes differentiated in the antheri- 
dium ; the larger and denser granular portion moves into 
the centre of the cavity, forming there an irregular and some- 
what indistinct strand, the gonoplasm, while a thin layer, the 
periplasm, remains next the wall of the cell. Then the gono- 
plasm passes slowly through the fertilization-tube which has 
[Annals of Botany, Vol. XV. No. LX. December, 1901,] 
