200 KEY TO SUB-CLASSES, ORDERS AND GENERA. 
OXX VIII— POLY PODIACE Ai—cont. 
(2) Involucre coriaceous, globose, stalked ; receptacles medial on lower 
anterior venulhes; rhizome large, globose ; fronds tripinate:— mliii—Spheeropteris, 
(3) Involucre half-cup shaped; tree ferns; fronds pinnate, bipinnate, or 
decompound:-—-... a ... mlix—Hemitelia. 
(11) Ring surrounding ‘sporangia ver tical, nearly completo ; sporangia usually 
stalked, gibbous, bursting tranversely :— 
(i) Sori furnished with an indusium ; fronds herbaceous or coriaceous, opaque :— 
(L) Sori marginal or submarginal :— 
(A) Indusium opening apically towards edge of frond, “apical or sub- 
apical on @ vein; sori discrete; shrubby ferns with thick 
creeping caudex ; fronds tripinnate :— ... wailiv—Dayallia, 
(B) Indusium opening "inwardly towards the midrib of the frond ; 
sori on a slender filiform receptacle in the axis of the indusium, 
connecting several veins, linear and continuous; shrubby ferns, 
tufted or with creeping rhizme: fronds various :— ... mly—Pteris. 
(2) Sori remote from the margin of the frond: — 
(A) Indusium linear or oblong :— 
(a) Indusium membranous, parallel and close to, and opening to- 
wards, the midrib; tree ferns with stout sealy caudex ; fronds 
pinnate :— mlvi—Blechnam, 
(b) Indusinia divergent from midrib, single, call opening towards 
midrib, or double and opening both towards midrib and 
towards wargin of frond ; small tree, or shrubly ferns ; fronds 
usually bi(sometimes simply or tri-) pinnate :— mlvii—Asplenium. 
(B) Indaosium reniform :— 
(a) Fronds simple, articulated, veins parallel, forked, soriterous at or 
near the base ; semi- scandent small tree fern:— mlxvili—Oleandra, 
(b) Fronds mostly pinnate, pinnae mostly divided, not articulate, 
nor white dotted above ; shrubby ferns:— mlyiii—N ephrodium, 
(c) Frond spinnate, pinnae always simple, articulate at base and with 
white cretaceous dots above; shrubby ferns:— mlxi—Nephrolepis, 
(ii) Sori without indusium :—~ 
(1) Sori on the back of the lobes confined to the veins, round or very 
slightly oblong ; shrubby ferns with erect or creeping caudex; fronds usually 
pinnatifid atapex, increasing to bi-or-tri-pinnate below :— mlxii-—Polypodium. 
(2) Sori not confined to veins, but occupying the whole, or nearly the 
whole, undersurface of the frond :— 
(A) Margin of frond not revolute to form a false indusium ; shrubby 
or climbing ferns; fronds simply pinnate :-—— mlxiii— Acrostichum. 
(B) Margin of frond revolute to form false indusium ; shrubby fern ; 
fronds pinnatifid :— mlxiv—Lomaria, 
CXXIX—SCHIZMACEA— 
(1) Characters of the Order (q.v. in the Syncpsis) :— 
CXXX—MARATTIACEAi— 
(1) Sporangia without any ring, opening by a slit down one side, or by a pore 
at the apex, dorsal:— 
(i) Sporangia free, crowded in two opposite linear series ; large shrubby 
ferns ; fronds very large, bipinnate, with 2 fleshy persistent stipuliform append- 
ages :— : mlxvi—Angiopteris. 
(ii) Sporangia coner rete, in two opposite linear series ; lar ge shrubby ferns 
leayes bipinnate, pinnae serrate :— mlxvii—Marattia, 
(II) Sporangia with rudimentary ring, bivalved, on rachiform portions of 
fronds, or separate fronds, forming a panicled inflorscence ; fronds pinnate or 
pipinnate : - ES eee Bes oes 5x8 ml xviii—Osmunda. 
CXXXI—LYCOPODIACEA— 
(1) Characters of the Order (q.v. in the Synopsis) :— 
mlxsy-—Lygodium. 
mlxix—Lycopodium, 
