BOTANICAL GAZETTE. 237 
and form a sphere, which is attached at one point to the remains 
of the epispore. The cortents of the sphere then divide so as to 
form a number of closely packed cells, the zoosporangia. e 
whole mass of zoosporangia constitutes a sorus. The zoosporangia 
soon separate from one another, and, when free, they are at first 
irregularly polyedral, but become afterwards more or less spher- 
ical. The contents of each zoosporangium then separate into a 
large number of zoospores, which escape by a rupture of the 
wall of the zoosporangium The individual zoospores have, in 
general, a circular form with a bright orange spot in the interior 
and a single cilium, or, in exceptional cases, two cilia. The zoo- 
Spores, after swimming about for an indefinite period, attach 
themselves to the epidermal cells of some host plant and again 
develop into resting spores. In the second mode of germination 
the endospore and its contents do not protrude in the form of a 
bladder, but are transformed into zoosporangia while within the 
€pispore, 
new Testing spores are produced in the host'cells. The species 
Which develop in this way are placed by de Bary in the sub- 
'nto the epidermal cells and grow into large cells which gener- 
ly almost completely fill the host-cells. These large cells are 
Sori, and 
Pung spores at the end of the season. Ina few of the species of 
Cusynchytrium, the summer sorus does not fill the host cell, but, 
hd ; 1 Mature, the wall of the sorus ruptures within the host-cell 
| h of zoosporangia is set free in the host-cell, the wall 
€ sorus remaining behind as a shrivelled membrane: oe 
Se who wish t he formation of the sori and zoo- 
"Pores will find cellent ites in the species which forms bright 
