162 BENGAL PLANTS. [Artificial Guide 
Fronds long petioled, with 4 terminal obcordate to cuneate segments; 
cles 
See er evesseceserces 
tPlants floating on the surface of ponds and rice-field swamps:— : 
(p. 161 
Fronds ential with po we cae anastomosing acsre me 
. Salvinia. o 
Fr small, deeply lobed, each lobe 1-nerved oe i Azolla. 
oPenveaertar’ or epiphytic herbs: —[p. 161] 
Leaves very small in proportion to the stem, or abse aA 
Stem articulate, simple or with whorled RRO leaves reduced 
to rings of teeth at the nodes; sori on underside of peltate bracts 
making a terminal cone-like frtictification ; ; erect in bud 
1156. Eq ‘ 
Stem not articulate, as or dichotomously branched ; leaves not — 
whorled ; circinate n bud; sori in axils of bracts or leaves, ee 
seattered along sala or aggregated in terminal cone-like fruc 
tions :— 
Sporangia of 2 sorts, one with |. large spores, one with more 
numerous small Son leaves usually 4-stichous and 2-morphie, 
rarely u nifo Bn, orem cece il 
Sporangia all of one sort with many small spores ; ‘eat almost 
always sate and usually multifarious : 
Leaves many, crowded; sporangia orbieuar, compressed 
~valved L co 
+ © Ctecvecsseese 
rl a Selg Seagal i eee Fee pn pee 
3-valy, 
Leaves fronts gy lange i in proportion to the stem or roatatook: stem 
never arti 
WGHa, : cong in he, 
barren portion :— 
Sterile portion of frond simple or, rarely, palmately lobed 
1151. Ophioglossum- 
oD gp 1152. Helminthostachys- 
divided more or less deeply into a fertile and & 
Sterile portion of frond digitate 
Fronds circinate in bud :— 
— opening by a lateral slit or an apical pore but without 
guia sori dorsal or mar inal :— 
Sporangia sessile, contiguous but discrete, arranged in bands 
near the edge of the pinne ; fronds 2-pinnate, veins free 
1149, 
Sporangia concrete in raised circular dorsal ae with hollow 
centre ; fronds palmate, veins anastomosing...1150. Ka’ 
Sporangia provided with a more or less elastic ring :-— 
