FILICES. 8 1 



Sori mostly on the back of the veins ; indusium orbicular or reniform, 



opening all round the margin XX. ASPIDIUM, p. no 



Sori at the end of a free vein ; indusium reniform, opening toward 

 the margin of the frond ; fronds simply pinnate, the pinna? articu- 

 lated to the rachis XXI. NEPHROLEPIS, p. 117 



i Indusium roundish or stellate, delicate . . XXIV. WOODSIA, p. 119 

 K A Indusium cup-shaped, somewhat two-valved, 



XXV. DICKSONIA, p. 121 



{Sori all parallel to the midribs or rachises M 

 Sori all oblique to the midribs O 

 Sori partly oblique and partly parallel to the midrib ; frond simple, 

 I tapering to a point . .... . XVIII. CAMPTOSORUS, p. 108 



| Veins free . N 



] Veins reticulate XV. WOODWARDIA, p. 102 



( Indusium near the margin ; fertile frond much contracted, 



XIII. LOMARIA, p. 101 



j Indusium remote from the margin ; fronds nearly uniform, 



XIV. BLECHNUM, p. 102 



(Sori on the upper side of a veinlet, rarely on both sides, 

 XVI. ASPLENIUM, p. 103 



1 Sori confluent in pairs, with an apparently double indusium open- 



( ing in the middle XVII. SCOLOPENDRIUM, p. 107 



{ Sori spread in a stratum on the under surface of the frond, 



I. ACROSTICHUM, p. 82 



j Sori roundish, or not more than twice as long as broad ... Q 



[ Sori usually linear, always more than twice as long as broad . K, 



[ Stipes articulated to the rootstock ; fronds (in our species) entire or 



~ simply pinnate . . ". . . \ . . . . II. POLYPODIUM, p. 82 



I Stipes not articulated to the rootstock; fronds (in our species) 



bi tripinnatifid or ternate XIX. PHEGOPTERIS, p. 108 



* Fronds simple S 



( Fronds pinnate to quadripinnate T 



i Fronds very narrow, grass-like ; veins indistinct, free, 



S VI. VlTTARIA, p. 89 



' Fronds broader ; veins anastomosing .... V. T^ENITIS, p. 88 

 f Sori marginal, more or less confluent in a marginal band, 



T IV. NOTHOL^EXA, p. 85 



I Sori following the veinlets, simple, forked, pinnate, or variously 



[ anastomosing III. GYMXOGRAMME, p. 84 



\ Sporangia ovate, with transverse ring at apex * V 



' Sporangia globose without a ring .... XXX. OSMUXDA, p. 124 



r i Stems scandent, pinnae palmate . . . XXVII. LYGODIUM, p. 122 

 1 Stems not scandent W 



_~ \ Sporangia in close distichous spikes . . XXIX. SCHIZ^EA, p. 123 

 < Sporangia in copiously branching panicles, XXVIII. AXEIMIA, p. 123 

 6 



