134 
BEAUTIFUL FERNS. 
ovate-lanceolate and pointed, narrowed to a sub-cordate and 
obscurely-stalked base, and deeply pinnately-lobed. This is 
var. elegans of Professor Robinson. Professor Lawson has 
a var. Traillce, which has “ very large bipinnate fronds, all 
the pinnules pinnatifid.” A very common form noticed by 
Mr. L. M. Underwood in Bulletin of the Torrey Botanical 
Club, has fronds only four or five inches long, the lower 
pinnae only pinnatifid and the upper ones lobed, the sori 
mostly solitary on the lobes. 
The veins and veinlets of the frond are very distinct, 
being marked by depressions in the upper surface in the liv- 
ing fronds, and visible as dark lines in the dried specimens. 
The veins fork near the midvein; the upper branch may be 
fertile at its tip; the lower branch is either simple, or forks 
a second, and perhaps a third time. All the veinlets are 
curved. On account of the venation Presl referred this plant 
to his section Arthrobotrys. 
The sori are close to the margin of the lobes, and vary 
from one to twelve to a lobe. They are very large and 
prominent, and have firm lead-colored orbicular-reniform indu- 
sia, which are slightly incurved round the edge, and depressed 
at the sinus. As the fronds mature the indusia become 
brownish. The spores are ovoid-reniform and have a narrow 
crenulate wing. 
