ULY 
30 BOTANICAL GAZETTE (J 
germinate during February and March. These two kinds pada 
lings grow in the same location, often side by side, during heat 
of the season, and from the next October to December the fi 
from zoospores develop into the adult form of the game = 
and those from gametes into the adult form of the Sporophy ; 
The condition of Zanardinia as it occurs in nature is in accor 
i ological evidence. 
ete herraarane study of Zanardinia another type of the 
brown algae has been shown to have an alternation of generations 
in its life history. 
Summary ~ 
t. The nucleus of the gamete-bearing plants contains 22 chro- 
Mosomes and the male and female gametes contain the same 
number. 
2. In the union of the gametes the n 
chro 
into 
umber is doubled, and 44 
sporeling, which develops 
chromosomes. 
producing plants contains 44 
reduced in zoospore formation, 
osomes. The zoospore with the 
mosomes germinates and develops into an 
mosomes. 
4. It is evident that the gamete-bearing plants come from zo0- 
Spores and that the zoos 
pore-bearing plants come from fertilized 
gametes, so that the two gene 
y germinate apoga- 
mously. There is no irregularity j 
mosomes being invariably pres 
external morphological charac 
the fertilized gamete, but the { 
not determined. 
University OF Cuicaco 
