THE COMMON PRICKLY SHIELD FERN. 125 
erectish or more or less spreading, occasionally somewhat drooping; 
lanceolate in form, bipinnate. Pinne numerous, obliquely-lanceolate, 
broadest at the base, acuminate, pinnate at the base and. for a part 
of their length, sometimes nearly to the apex, in other cases the 
basal pinnules only being distinct; the upper ones alternate, the 
lower ones nearly opposite and diminishing in size. Pinnules ovate- 
falcate or elliptic, acute and aristate at the apex; all or the basal 
ones only auriculate on the anterior side, the auricle acute and 
mucronate; aristate, subsessile, and attached by the wedge-shaped 
base, or decurrent; the basal portion entire, and when distinct, 
obliquely incised on the posterior side, truncate on the side next their 
rachis; the rest of the margin toothed with unequal adpressed 
mucronate serratures. The basal anterior pinnule on each pinna is 
generally larger, often much larger than the rest, and more strongly 
auricled, and the pinnules are all more or ‚less convex; on the 
under surface are scattered fine hair-like scales. The typical form 
of the species has the pinnules mostly distinct; the variety lobatum 
has them mostly decurrent, while in some plants of the latter, appa- 
rently resulting indifferently from youth or decrepitude, they are 
obsolete, the pinne being merely more or less deeply lobed and 
toothed, somewhat resembling those of P. Lonchitis, and hence 
specimens in this state are sometimes named Jonchitidoides. 
Venation of the pinnules consisting of a flexuous costa or midvein, 
with alternate branches or veins, which are again furcately-branched 
alternately, the lower veins producing three or four, the upper two 
or three branches or venules, of which the lowest anterior one of the 
fascicle is soriferous. In the auriculate portion at the base, the vein 
is more prominent than in the upper portion, and gives off a greater 
number of simple or forked ‘venules, some few of which on both 
sides may produce sori. 
Fructification on the back, and usually confined to the upper half 
of the frond. Sori, round, indusiate, seated much below the apices 
of the venules, in a line on each side of the midvein of the pinnules, 
and also of the vein of the auricles; often crowded, sometimes 
becoming confluent ; attached to the lowest anterior venule of the 
fascicle of veins, or, at the auriculate base, to the venules on 
either side the vein; but there also to the anterior branch if 

