Jamesoniane. N. O. Filices. 
DCCCCXLVIII. 
* 
POLYPODIUM SEMIADNATUM, Hook. 
Frondibus linearibus acuminatis longissimis petiolatis pinnatis, 
pinnis approximatis rigido-membranaceis suboblique ovatis 
obtusis crenato-lobatis basi superiore subauriculatis longe 
ciliatis basi coste adnatis, subtus petiolo gracili epaleaceo 
rachique filiformibus nigris patenti-hirsutis, venulis furcatis, 
venula superiore apice sorifera. 
Has. On trunks of trees, Pilzhum, 12,000 of elevation on the 
Quitinian Andes, Prof. Jameson. 
When Ferns are pinnated there is commonly a contrac- 
tion or constriction as far as the midrib, which even in a 
sessile pinna is usually the only point of attachment to the 
rachis, unless in the cases where the pinne are decurrent. 
Here, on the other hand, the pinne are not decurrent, yet is 
portion of the very elongated frond are the pinne confluent 
or decurrent, Our specimens are a foot, and a foot and a half 
long, the stipes is from two to four inches long. 
Fig. 1. Pinney, seen from above. f. 2. Fertile pinne seen 
from beneath *—magqnified, 
