﻿FiucES. 5 



Key to the families. 



a. Sporangia with a ring. 

 b. Ring complete. 



c. Ring obli(jue, sub vertical. 



d. Ferns arborescent. Indusium wanting or present, but 

 '■ then neither linear nor umbrella-shaped. 



I. Cyatheaceae. 

 d.d. Ferns not arborescent. Indusium linear or umbrella- 

 shaped. 



e. Indusium umbrella-shaped. II. Ulatoniaceae. 

 e.e. Indusium linear. 



VI. Polypodiaceae, No. 40, Plagiogyria. 



C.C. Ring + horizontal, surrounding the sporangium like a belt. 



«. Receptacle inconspicuous, dot-like. Indusium wanting. 



III. Grleicheniaceae. 



id. Receptacle conspicuous, erect, oblong to columnar-filiform. 



Indusium present. IV. Hymenophyllaceae. 



c.cc. Ring operculiform, crowning the apex of the sporangium. 



V. Scliixaeaceae. 

 b.h. Ring incomplete. 



X. Ring vertical, long, the extremities sometimes separated by 

 the stalk of the sporangium only. 



.'. Sori indefinite. Sporangia scattered irregularly on the 

 few, longitudinal veins. VII. I^ai*k.eriaeeae. 

 .'..'. Sori definite or indefinite, but then the sporangia densely 

 crowded over the pai-enchyma. 



VI. Polypodiaceae. 

 x.x. Ring horizontal, short or consisting of a lateral group of 

 thickened cells only. VIII. OiSBnundaceae. 



«.«. Sporangia without ring. 



*. Sori on the under surface of normal fronds. 



IX. Marattiaceae. 

 *.*. Sporangia not gathered into sori, placed on much contracted, 

 spicate or paniculate segments originating from the base, the 

 centre or the margin of the leafy, barren segment. 



X. Ophiogloisisaceae. 



