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THE FERNS OF SOUTH AFRICA 
CLASSIFICATION OF FERNS AND 
FERN ALLIES 
Key to the Cohorts . 
PTERIDOPHYTA. 
Vascular cryptogamic plants, having in the higher forms 
a distinct and evident alternation of generations consisting 
of (i) a vegetative prothallus, more or less developed, either 
monoecious or dioecious, on which sexual organs produce 
fertilisation, resulting in (2) the more complex plant which 
is recognised as the Fern and Fern-ally species, and on 
which unfertilised spores are produced, which after falling 
from the parent produce prothalli similar to those of the first 
stage, and repeat the process. In certain of the lower forms 
the vegetative prothallus is less evident, or has to be assumed, 
but the sexual fertilisation occurs at that stage. 
COHORT I. FILICALES. Sporangia in sori, mostly in lines or dots 
or scattered, on the under-surface of the frond ; vernation 
circinate. 
(1) Filicales Leptosporangiatae. Sporangia small, superficial or 
specialised, free or eventually free. 
A. Filices. Sporangia free, in sori on the under-surface or margin 
of the frond ; sporangia and spores all alike. (All ordinary 
ferns.) 
B. Salviniaceae and Marsiliaceae x . Sporangia and spores of two 
kinds, specialised, eventually free. ( Azolla and Marsilia.) 
(2) Marattiales. Sporangia large, without rings, permanently 
united, opening by slits down their inner faces ; vernation 
circinate. ( Marattia!) 
(3) OPHIOGLOSSALES. Sporangia large, 2-valved, without rings, sunk 
into a fertile frond, and opening by a slit ; vernation erect. 
( Ophioglossum . ) 
1 = Hydropteridineae^ = Rhizocarpeae of our first edition. 
