78 AMERICAN FERN JOURNAL 
The leaves of P. glabella are very bluish green, with 
the lower surface distinctly punctate, and bearing a few 
hair-like scales along the midrib. When mature, the. 
leaves are rather thick, and have very obscure veins, 
which leave the midrib at a narrow angle, fork about 
twice, and in the outer part of the leaflet make an angle 
of about 60° with the midrib. The midrib itself is 
marked by a slight ridge on the upper side of the leaflet, 
and is very obscure below. The leaves of P. Suksdor- 
fiana are much less blue, the lower surface of the leaflets 
is somewhat less obviously punctate, and is glabrous. 
The veins are somewhat conspicuous by transmitted 
light, leaving the midrib at a narrow angle, forking 
about twice, and in the outer part of the leaflet making 
an angle of about 45° with the midrib. The midrib is 
marked by a slight groove on the upper side of the leaflet, 
and is somewhat prominent below. The leaves of P. 
pumila are less blue than those of P. glabella, the lower 
surface of the leaflets is not punctate, or at most very 
obscurely so, and is glabrous. The veins are somewhat 
more obscure than in P. Suksdorfiana, and are about 
once forked. They leave the midrib at an angle of 30° 
45,° and in the outer part of the leaflet make an angle of 
about 60° with the midrib. The midrib is scarcely 
visible on the upper side of the leaflet, and is obscurely 
ridged below. 
The whole indusium of P. glabella is 0. 7-1. 3 mm. 
wide, with a nearly entire hyaline margin 0. 2-0. 3 mm. 
wide. It reaches very close to the tip of the leaflet, or 
may even extend across the tip from one side of the 
leaflet to the other. The band of sori is narrow, and is 
situated on the back of the leaflet close to the angle be- 
tween the leaf surface and the indusium. Accordingly 
the sporangia are seldom conspicuous, even in mature 
fronds. In P. Suksdorfiana the indusium is somewhat 
