eT 
[Reprinted from Ruopora, Vol. 19, No. 225, September, 1917.] 
ISSUED 
CT 11 1917 
CONTRIBUTIONS FROM THE GRAY HERBARIUM 
OF HARVARD UNIVERSITY. 
New Series.— No. LI. 
TAXONOMIC AND GEOGRAPHIC Stupies IN NortH AMERICAN FERNS. 
@ ee Genus Athyrium and the North American Ferns allied 
o A. Filix-femina. 
if, ee virginianum and its American Varieties. 
F. K. Burrers. 
170 
207 
