INTRODUCTION. 
V 
to the frond hy its centre on the upper branches of the side- 
veins. 
Lastrba. —Masses nearly circular on the hack of the 
side-veins; covering irregularly kidney-shaped, attached to 
the frond at the indentation in its kidney shape. 
Cistoptehis. —Masses small, nearly circular, seated at 
the hack of the main side-veins; covering hood-like, fixed 
by its broad base beneath the masses, which it covers when 
young, the margin where it opens fringed, finally turned 
hack. 
Asplenium.—M asses in lines, placed on the lateral veins; 
covering membranaceous, flat, opening towards the mid¬ 
vein. 
Athyriuit. —Masses nearly circular, scattered; covering 
solitary, circular, peltate, or kidney-shaped, attached to the 
frond hy its centre or side, opening on the side next the 
mid-vein, and edge of opening fringed, the fringe turning 
hack. 
Scolopendrium.— Masses line-like, oblique, double, op¬ 
posite, parallel; oovering membranaceous, opening in the 
middle over the masses in opposite pairs. 
Pteris. —Masses on the margin of the leaflet in an unin¬ 
terrupted line; covering opening from the bent-in edge of 
the frond. 
Allosorus. —Masses circular, placed on the transverse 
forked veins, finally covering the back of the contracted 
leafit; covering very narrowed, formed by the rolled-back 
edge of the leafit; seeds triangular. 
Blechnum.— Masses in continuous line next each side of 
the mid-vein ; covering membranaceous, flat, opening next 
the mid-vein. 
Adianium.— Masses line-like, or partly round, on the 
