Six of these Tribes including fifteen genera are represented on 

 the Pacific Coast. This limitation, it will be found, greatly fa- 

 cilitates acquaintance with this beautiful class of plants. 



SYNOPSIS OF TRIBES AND GENERA.— SUB-ORDER 

 POIiYPODIACEiE. 



Sporangia globular, or slightly flattened laterally, collected in 

 patches, dots, or lines, called sori., of various shapes, all stalked 

 and provided with a vertical, incomplete, many-jointed ring of 

 larger cells, which straightens at maturity, bursting the less firmly 

 united wall plates, and scattering the minute spores. These 

 sori are either naked or covered by indusium in several ways. 



TRIBE 1, POLYPODIES. Indusium none. Sori round or 

 oblong, placed on or at the ends of the veinlets. Stalk articulated 

 to the creeping root ; containing but one genus. 



1. PoLYPODiuM. Character same as the Tribe. 



TRIBE II, GRA.AIMITIDES. Indusium none. Sori more 

 or less elongated, placed on the under side of the fronds or into 

 divisions, and either following along the veins or collected at 

 their tips, near the margin. Fronds either scaly, tomentose, or 

 powdered beneath. Two genera. 



2. Gymnogramme. Sori much elongated, following the veins, 

 and, like them, often branched. 



3. NoTHOL^ENA. Sori but little elongated, often of very few 

 sporangia, placed across the veins, near the margins of the frond 

 or its lobes. 



TRIBE III, PTERIDES. Involucre consisting of the mar- 

 gin of the frond turned inward, and covering, when young, the 

 sori, which are close to the margin or extending down the veins. 

 Five genera. 



4. Cheilanthes. Sori minute, at the ends of the veins, cov- 

 ered by a usually interrupted involucre. Ferns small, often 

 wooly, scaly, or glandular. 



5. Pell^ea. Sori near the ends of the veins, often confluent. 

 Involucre continuous around the pinules. Sterile and fertile fronds 

 much alike and smooth, the stalk dark-colored. 



G. Cryptogramme. Sori extending down the free veins. In- 



