28 BOTANICAL GAZETTE [JULY 
at the base of the filament there are produced laterally and in 
succession a number of filaments whose marginal union forms a 
funnel or cup, while their free ends appear as hairs growing on the 
margin of the cup. The outer morphology of this new product 
of zoosporelings is similar to that of the germinating fertilized 
gamete. 
Alternation of generations 
In Zanardinia the plant bearing gametangia has a nucleus with 
22 chromosomes in both the vegetative and germ cells, and the 
number is doubled at fertilization by the union of the sexual 
nuclei. From this fact, the gamete-bearing plant of Zanardinia 
is the x generation, and the ox generation begins at the fertilized 

| 8) Ns 
Fic, 24.—Sporelings from zoospores two or three days old. a J) 
*y.8 “. 4 
gamete. The fertilized gamete germinates with- ‘s 
out any reduction of chromosomes, retaining | 
potentialities of the new Phase initiated at the yp 
there is de 

