96 BOTANICAL GAZETTE [JANUARY 
I wish to express my appreciation of the helpful criticism of 
Dr. W. J. G. LAnp. 
UNIVERSITY OF CHICAGO 
EXPLANATION OF PLATES 
Fig. 3, X63; all others, X450 
Fic. 1.—Simple columella at time of separation of spores from tetrads, 
showing ie cluster of elaters and disorganized sporogenous tissue. 
1G. 2.—Columella immediately preceding thickening of elaters; composed 
largely ce halts of sporogenous cells which failed to reach spore mother cell 
stage. 
Fic. 3.—Median view of sporophyte giving topography. 
Fic. 4.—Young sporophyte preceding isolation of sterile cap cells; un- 
feieilized egg beside sporophyte. 
Fic. 5.—First isolation of sterile cap cells preceding elongation of sporoge- 
nous cells. 
Fic. 6.—Cap cells readily distinguished at time of invasion of foot; wall 
cells a to sterile cap group. 
G. 7.—Unusually large mass of sterile cells, 4 deep at apex. 
Fre 8.—Close relation of radiating elaters to apical group, tetrad stage. 
