Plate 11. 
ASPIDIUM (Polystichum) aculeatum, L. 
Prickly Shield-Fern. 
% 
Var. /3. INTERMEDIUM. 
Aspidium (Polystichum) aculeatum; cautlex short, erect, stout, knotted, densely 
paleaceous with rusty^coloured ferruginous scales often half an inch and 
more long, ovate, with finely acuminated points, and these extend up the 
stipes for some way, and gradually on the rachises and under sides of the 
costse become smaller and subulate; stipites short, stout; fronds one to 
two feet and more long, oblong-lanceolate, acuminate, bipinnate, rigid cori¬ 
aceous; primary pinnae approximate from a broadish subpetiolated base, 
very acuminate, subfalcate; pinnules close, ovate, spinuloso-acuminate, free 
and subpetiolulate, or more or less decurrent and united to the adjacent 
ones, the margins sharply and strongly spinulosely or setosely serrated, the 
superior basal ones generally larger than the rest, and more or less auricled ; 
veinlets once or twice forked; sori in two rows, nearer the costa than the 
margin. 
Var. /3. intermedium; frond rigid, submembranaceous, pinnules distant, subsessile, 
several of the lower ones auricled, serratures spinulose. (Our Plate 11.) 
Aspidium aculeatum. Sw. Syn. in Schrad. Journ. 1800. v. 2. p. 37. Willd. 
Sp. PI. v. 5. p. 258. Sm. Ft. Brit. p. 1122. Engl. FI. v. 4. p. 277. Engl. 
Bot. t. 1562. Hook, and Am. Brit. FI. ed. 8. p. 582. 
Polypodium aculeatum. Huds. Angl. p. 459. 
Polystichum aculeatum. Both , FI. Germ. v. 3. p. 79. Moore , Brit. Ferns , 
Nat. Print. ^.10. 
Hab. {Var. /3. intermedium.) Equally common in Great Britain with the pre¬ 
ceding form of A. aculeatum , var. lobatum, given in our last Plate, and in¬ 
habiting similar localities. 
Although this is by many thought more closely united to the 
var. lobatum than to var. angulare , so much so that some who 
unite it with A. lobatum keep angulare distinct, yet it is more 
difficult to express the difference in words from the latter. Lo¬ 
batum has the pinnules mostly sessile, and decurrent with the 
pinnule next below, so that when the plant is held up between 
the eye and the light, the pinnae are seen to be rather pinnatifid 
than pinnate. In our present plant, in the same point of view, 
the pinnules are seen to be subpetiolulate, or at most sessile. 
Its distinction from angulare depends mainly on the larger size of 
the pinnules and on the presence of auricles on more than one 
of the inferior pinnules. 
Plate 11. Fig. 1, 2. Frond of Aspidium (Polystichum) aculeatum ., var. 
intermedium:—natural size. 3. Pinnule, with a small portion of the rachis. 
4. Single sorus :—more magnified. 
