﻿S52 45a. PTERis. 



Arrangement, of the sections and groups. 



§1. EUPTERIS. Veins free. 



a. Pinnatifidae. Fronds pinnatifid throughout, at best pinnate 

 at the very base. 



b. Pinnatae. Fronds 5-foliate or pinnate, the lowest pinnae simple, 

 or forked with 2 — 3 undivided segments in the barren fronds. 



c. Compoisitae. Fronds 3-foliate or pinnate, the lowest pinnae at 

 least pinnatifid in the barren fronds. 



4;. Blplnnatifidae. Fronds not 3- or 5-partite; lowest pinnae not 

 much longer than the next higher ones and similarly pinnatifid 

 or pinnate, with the lowest segments on the lower side not 

 rarely elongate and divided again. 

 >^c.^. Partitae. Fronds 3- or 5-partite; lateral branches nearly 

 as long as the central one and similarly 2-pinnatifid, with 

 the lowest segments on the lower side not rarely elongate and 

 divided again. 

 §2. CAMPTERIA. Veins slightly anastomosing, forming 1 single row of costal 



areolae on each side, otherwise free. 

 § 3. LITOBROCHIA. Veins anastomosing more copiously. 



Key to the sections and groups. 



a. Veins free. § 1. EUPTERIS. 



h. Fronds pinnatifid, at best pinnate at the very base. 



§ 1, a. Piiiiiatifi«lae. 



h.h. Fronds 3-foliate, pinnate or more compoundly divided. 



c. Lower primary segments simple, or forked at the base with 

 2 — 3 undivided secondary segments in the barren fronds. 



§ 1, b. Pinnatae. 

 c.C' Lower primary segments at least pinnatifid in the barren fronds 



§ 1, c. Coin|iositac. 



d. Fronds not 3- or 5-partite, i. e. the lowest pinnae not 



much longer than and similarly pinnatifid or pinnate as 



the next higher ones, but not rarely forked at the base 



with similarly divided branches. § 1, c*. Blpinnatifldae. 



d.d. Fronds 3- or S-partite, i. e. the fronds divided into 3 or 



