THE SHIELD FERN. 
49 
is carried out to the margin of the pinnule, the sori 
thus being placed nearer to the point of forking or 
branching than to the apex of the venule ; while in 
P. angulare the fertile venule stops about midway 
across the pinnule and the sorus is generally placed 
at or almost close to the apex. The basal pinnules 
and the portion rather below the middle of the frond 
should be taken for examination. The upper parts of 
the fronds alone, in these Polystichums, are useless 
for the purpose of identification. 
The Soft Prickly Shield Fern is one of our most 
graceful ferns, strong-growing and tufted-stemmed, 
sometimes forming great masses, the fronds lanceolate 
and rising to the height of from two to five feet, lasting 
through ordinary winters and in sheltered places re- 
taining their verdure until the new fronds are pro- 
duced, the old fronds only gradually dying off as the 
new ones become developed, in or about May. The 
stipes, varying from a third to a fourth of the length 
of the whole frond, is very shaggy, with reddish chaff- 
like scales continuing though decreasing in size 
throughout the upper portions of the frond. The 
fronds are bipinnate, with numerous tapering distinct 
pinnae, having their pinnules flat, and somewhat 
crescent-shaped, from the prominent auricle at the 
anterior base, often bluntish at the apex but some- 
times acute, always with spinulose marginal serratures, 
and sometimes in a few of the lower pinnules with 
deep lobes so that the pinnules become pinnatifid. 
The pinnules taper to an obtuse or right-angled base, 
and are attached, as before said, by a slender stalk, 
E 
